# Dive Bomber Comparison



## davebender (Jul 23, 2010)

*Ju-88A.* Requirement issued August 1935. Operational fall of 1939. 
This is a 1942 version. That’s when the 1,400 hp Jumo 211J engine entered service.
2 x Jumo 211J V12 engines. 1,400 hp each. 
317 mph max speed. (Clean configuration).
7,937 lbs max bomb load. Normally carried externally due to bomb bay being rather cramped.
1,429 miles max range on internal fuel.
Can deliver weapons very accurately due to being a dive bomber.

*AD-1 Skyraider.* Prototypes ordered July 1944. Operational 1947.
This is the early version. Vietnam era versions had 2,700 hp.
1 x Wright R-335-24W radial engine. 2,500 hp.
321 mph max speed. I assume this is clean configuration.
7,000 lbs max bomb load. All external. Later versions could carry 8,000 lbs.
1,553 miles max range on internal fuel.
Can deliver weapons very accurately due to being a dive bomber.

Perhaps a meaningless comparison.
- Land based vs CV based.
- 1935 design vs 1944 design.

However I find it interesting that speed, weapons load, bombing accuracy and range are similiar for these dive bombers. Perhaps Germany would have considered replacing the Ju-88A dive bomber with something similiar to the AD-1 if the 2,500 hp Jumo222 engine had entered mass production.


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## gorizont (Jul 27, 2010)

davebender said:


> However I find it interesting that speed, weapons load, bombing accuracy and range are similiar for these dive bombers. Perhaps Germany would have considered replacing the Ju-88A dive bomber with something similiar to the AD-1 if the 2,500 hp Jumo222 engine had entered mass production.



For what sake? In a role of dive bomber Ju-88 (as Ju-87 too) was to be substituted by Me-210.


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## davebender (Jul 27, 2010)

> In a role of dive bomber Ju-88 (as Ju-87 too) was to be substituted by Me-210.


I agree. That was the historical plan.

However having a 2,500 hp engine gives you another option. You can achieve similiar combat performance using a single engine aircraft. Less expensive to produce and a smaller target for enemy ground fire.


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## gorizont (Jul 27, 2010)

davebender said:


> I agree. That was the historical plan.
> 
> However having a 2,500 hp engine gives you another option. You can achieve similiar combat performance using a single engine aircraft. Less expensive to produce and a smaller target for enemy ground fire.



Germans have 2.500 Hp engine neither in 1942 nor in 1945. As mentioned in a topic in "Technical", Jumo 222 was planned to be 2000 hp class engine, and from beginning his take-off power proposed to be of 2000 hp. This variant wasn't ready for mass production due to technical problems which hadn't been overcame. As for more powerful variants of the engine.

As you know Junkers worked at another variant of Shtuka - Ju-87F, with Jumo 213A, but in 1943 it was cancelled.

P.S. and please remember that Skyraider is a post-war aircraft. Americans didn't manage to produce this aircraft before war ended. And R-3350 variants which were produced in mass during war period didn't produce 2,500 hp.

And finally - single-engined aircraft is cheaper but more vulnerable


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## VG-33 (Jul 28, 2010)

davebender said:


> I agree. That was the_ historical plan_.



If you consider the _historical plan_, in 1935 it was never concieved from the mainstream as a diver but as a _schnellbomber_, later modified by Udet cause to is own hobby for dive bombers.
But reading some late-war american repports in fact, as french user's experience it soon appeard than except in some german propaganda publications it never had 100% success in that rule as Ju-87, Pe-2, Helldivers did, as structure being a little to weak for such efforts. So 70° max with severe restrictions, 40-60° dive as usual. So we should call it limited-dive bomber. For instance:








> However having a 2,500 hp engine gives you another option.


Yes of course, having some..., my auntie would be my uncle.



> You can achieve similiar combat performance using a single engine aircraft.


At night, in stormy weather, over London ? With what navigation features to reach such a target?
And what about catching Lancasters at night, are you sure the Skyraider would be better?
Moreover, you should be more accurate in your performance table. 
What range, at what speed and with what load altogether for different values. And not independently one from the other.
Even in 1935 with bomb load carried in internal (limited drag), the Ju-88 was able to go far, and fast...

Other way, hard to compare apples and oranges.

Regards


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## davebender (Jul 28, 2010)

> If you consider the historical plan, in 1935 it was never concieved from the mainstream as a diver but as a schnellbomber, later modified by Udet cause to is own hobby for dive bombers.


I don't think Udet's hobby had anything to do with the German decision to emphasize dive bombing.

HyperWar: The Battle of Britain--A German Perspective


> Bombing Accuracy. Dive-bombing offered several advantages over level bombing. The limited bomb loads and the relative inaccuracy of the level bombers currently available required large numbers of aircraft to achieve the same level of results as dive-bombing could provide. As an example, the Ju87B-1 (the model in service in 1939-1940), "was to prove effective in the hands of expert pilots, who, in dives of eighty degrees to within 2,300 feet from the ground, could deliver a bomb with an accuracy of less than thirty yards. Even average pilots could achieve a twenty-five percent success rate in hitting their targets, a far higher proportion than that attained in conventional, horizontal attack bombers."26 By comparison, US Army air forces typically designated a radius of 1,000 feet as the "target area" aim point for the "pickle-barrel" bombing conducted in Europe. "While accuracy improved during the war, [US Strategic Bombing] Survey studies show that, in the over-all, only about 20% of the bombs aimed at precision targets fell within this target area."27
> 
> Generaloberst Hans Jeschonnek, chief of the General Staff of the Air Force from 1939-1943, and at the time head of the operations staff of the General Staff, saw dive-bombing as "the ideal solution to the bomber problem of 1937." That bomber problem was primarily the lack of an effective bomb sight for use with the level bombers. The standard sight was inaccurate and would require considerable practice to achieve acceptable results even for area bombardment. In 1938, "even well-qualified bomber crews could achieve only a two percent bombing accuracy in high-level, horizontal attacks (up to 13,500 feet), and twelve to twenty-five percent accuracy in low level attacks against targets of between 165 to 330 feet in radius, and to make matters worse, the bomb load of the German bombers was very low; only four 550 lb. bombs were carried by the Do17 and six by the He111. Thus, if the target were to be completely destroyed, the only way to compensate for inaccuracy would be to employ large numbers of aircraft."28 The Luftwaffe General Staff announced that, "the emphasis in offensive bombardment has
> 
> ...


Unlike the USA and Britain, the Luftwaffe conducted serious testing during the 1930s to determine bomber accuracy. Dive bombers were over 10 times as accurate as level bombers. That's why the Ju-88 was developed into a dive bomber and why RLM initially wanted the larger Do-217 and He-177 to dive bomb also. This was cutting edge technology during the 1930s. Nobody knew what the maximum size was for a dive bomber so they had to experiment. Dive bomber requirements for the Do-217 and He-177 were dropped after engineers determined it could not be made to work.


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## Juha (Jul 28, 2010)

Hello Dave

Quote: “…US Army air forces typically designated a radius of 1,000 feet as the "target area" aim point for the "pickle-barrel" bombing conducted in Europe. "While accuracy improved during the war, [US Strategic Bombing] Survey studies show that, in the over-all, only about 20% of the bombs aimed at precision targets fell within this target area."

and

Quote: “…when properly flown under test conditions, could deliver 50 percent of its bomb load within a 50-meter circle”

My interpretation is that USSBS gave actual results and the German result is a test result, and if so you really cannot compare the two results, you need test results from both types of bombing or and this is very much better option, the actual wartime results for both. And one must remember that around mid-war Germans stopped to use Ju 88s as dive bombers, removed the dive-brakes and used it as glide- or level-bomber only.

Juha


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## gorizont (Jul 28, 2010)

Juha said:


> My interpretation is that USSBS gave actual results and the German result is a test result, and if so you really cannot compare the two results, you need test results from both types of bombing or and this is very much better option, the actual wartime results for both. And one must remember that around mid-war Germans stopped to use Ju 88s as dive bombers, removed the dive-brakes and used it as glide- or level-bomber only.
> Juha



As far as I remeber among reasons were not only a weak to some dergee airframe but implementing new sights - Lofte 7 for horizontal bombing and Shtuvi 5 for dive-bombing. The last provided german bombers ability to achieve such an accuracy from glide-bombing (or shallow-dive bombing) that approximated to an accuracy of steep-dive bombing with common reflector sights.


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## Shortround6 (Jul 28, 2010)

davebender said:


> Unlike the USA and Britain, the Luftwaffe conducted serious testing during the 1930s to determine bomber accuracy. Dive bombers were over 10 times as accurate as level bombers. That's why the Ju-88 was developed into a dive bomber and why RLM initially wanted the larger Do-217 and He-177 to dive bomb also. This was cutting edge technology during the 1930s. Nobody knew what the maximum size was for a dive bomber so they had to experiment. Dive bomber requirements for the Do-217 and He-177 were dropped after engineers determined it could not be made to work.



The US certainly did conduct tests and also conducted some combat operations using dive bomber techniques during the 30s. Now maybe the Navy/marines weren't talking to the Army but the tests were being done. 

The aircraft engineers might have had a better idea than the German air staff as to what was possible since by popular history none of the companies making the larger aircraft wanted them to be dive bombers and usually fought against it.
In fact the engineers probably had a very good idea of what the dive bomber requirement was costing them. 
Assuming the large twin engine (or 4 engine) plane can dive bomb at all the heavier structure is going to cost in speed, or range, or bomb load or a combination of the three. 
Assuming you have 2400hp to play with (two 1200hp engines) you then have to decide how big the airplane is going to be, this depends on payload, range requirement, speed, landing speed and other performance requirements. The more "G"s you want the plane to pull ( and how many times, metal fatigue) the more weight goes into structure and the less weight is available for something else. The higher the empty weight (or low loaded weight ) the higher the landing speed and Junkers had already figured out quick dumping fuel tanks to lower the landing speed of commercial aircraft that had trouble on take off. You can't jettison structure. 

It doesn't matter how accurate your dive bomber is, if it can't reach the target (lack of range) or if it can't find the target (bad navigation skills/equipment) it is so much wasted metal and labor sitting on the runway or wandering about the sky. 

Turret fighters like the Defiant and bomber destroyers like the Airacuda were also considered cutting edge in 1937. Doesn't mean they were a good idea.


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## Juha (Jul 28, 2010)

Hello Gorizont
and IIRC Lofte 7 and US Norden sight were about equally accurate, IIRC in fact Lofte 7 was much based on Norden, Germans got Norden secrets by one agent. And yes, Stuvi 5 was an excellent sight, Finns also used Ju 88A-4s during the war.

Juha


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## gorizont (Jul 28, 2010)

Juha said:


> Hello Gorizont
> and IIRC Lofte 7 and US Norden sight were about equally accurate, IIRC in fact Lofte 7 was much based on Norden, Germans got Norden secrets by one agent. And yes, Stuvi 5 was an excellent sight, Finns also used Ju 88A-4s during the war.
> Juha



Hello Juha
For Lofte - as far as I know the only thing which is the same in Lofte and Norden - methods of calculation and algorithm of working. Both sights function in the same pattern. But technically they had absolutely diifferent designs.
Stuvi 5 was dive-bombing sights and on twin-engined germans bobmers it was assisted by BZA ="computer block". It works (automatically putting corrections to the position of a mark on sight glass according inputs of wind, speed etc processed by BZA) in range of dive angles from 25 to almost 90 as far as I know.

On Ju-88 and Do-217 usually were installed both sights (from 1942), Lofte for horizontal bombing and Shtuvi for shallow -dive bombing.

P.S. I was surprized then got to know from P. Smith' book about Skyraider, that americans used on it a rather simple reflector sight and pilot estimeted corrections in the same fashion as Dontless pilots did it in 41-42.


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## Juha (Jul 28, 2010)

Hello Gorizont
yes, Stuvi was a dive-bombing sight, even its designation gives that away. 

BTW, what was the normal dive angle of Skyraider during dive-bombing attack during the Korean War?

Juha


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## gorizont (Jul 28, 2010)

Juha said:


> Hello Gorizont
> yes, Stuvi was a dive-bombing sight, even its designation gives that away.
> BTW, what was the normal dive angle of Skyraider during dive-bombing attack during the Korean War?
> Juha



Juha, as far as I know Skyraider pilots were trained to attack from steep dive up to 70 degrees. They used fixed dispositions - they learnt by heart charts for deflections for angles of dive: 30, 50 and 70 dergee with charts of corrections for altitude, wind and speed.
But They hardly used steep-dive attack in Korea. As far as I guess steep-dive attack was proposed mainly vs naval vessels especially warships, aircraft carriers and cruisers, but in reality Skyraiders never had opportunity to strike such opponents.


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## Juha (Jul 28, 2010)

Thanks a lot for the info, Gorizont!

IIRC while most of the AD bomb attacks were made much shallower angles they sometimes used divebombing when they attacked bridges, which was a rather common target during the Korean War, maybe also during attacks on some other targets in mountainous areas.

Again Thanks!
Juha


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## gjs238 (Jul 28, 2010)

Not planes that could be used as dive bombers ala Ju-88, or were converted, but true blue dive bombers.

- Ju 87
- SBD Dauntless/A-24 Banshee
- SB2C Helldiver/A-25 Shrike
- D3A Val
- B-24 Skua
- He 118
- D4Y Judy
- Hs 123
- Hs 129 (not really a dive bomber?)
- Fairey Barracuda
- A-31 Vengeance
- SB2U Vindicator
- Northrop BT
- maybe others I've omitted


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## BombTaxi (Jul 28, 2010)

The crux of dive-bombing is having highly skilled crews - both the Stuka and Val became less effective as crews became less skilled. On the other hand, a formation of B-17s needs one guy who can use a Norden sight, and a large group of guys who can pull a toggle... It's cheaper, if less accurate. But unless you're going after ships or bridges, accuracy is less vital than the ability to put a lot of bombs into a relatively small area.


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## davebender (Jul 28, 2010)

> Not planes that could be used as dive bombers ala Ju-88, or were converted, but true blue dive bombers.


??
The Ju-88A was a "true blue" dive bomber complete with dive brakes and proper dive bomber sight.


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## gorizont (Jul 28, 2010)

BombTaxi said:


> The crux of dive-bombing is having highly skilled crews - both the Stuka and Val became less effective as crews became less skilled.



There is another way - more sophisticated aiming devices than simple optic or reflector sight - the way chosed germans and japanese.So demand for skill - not disappearing - was diminished to some degree. Anyway successful use of dive-bombers demands at least local air superiority and/or good tactic including coordination between groups in airstrike and surprise of attack.
In 1941 two Italian low-level aircraft provided success of attack Shtukas on _Illustrious _ by drawing british attention away from incoming dive-bombers. And you know factors which gave such a success to dive-bomber attack at Midway.



BombTaxi said:


> On the other hand, a formation of B-17s needs one guy who can use a Norden sight, and a large group of guys who can pull a toggle... It's cheaper, if less accurate.



I don't think that this is cheaper unless You mean bombing for area in the depth of hostile territory. But dive bombers hardly reach such objects.



BombTaxi said:


> But unless you're going after ships or bridges, accuracy is less vital than the ability to put a lot of bombs into a relatively small area.



Shtuka CEP was 30 metres. What was CEP for B-17?


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## BombTaxi (Jul 28, 2010)

_Shtuka CEP was 30 metres. What was CEP for B-17? _

My point is that you don't need a 30m CEP unless you're going after a ship or a bridge. So for most targets, level bombing or shallow-dive attacks will do. In the specific case of a B-17, most targets were so big that getting the bombs into the correct postcode would do the job.

_I don't think that this is cheaper unless You mean bombing for area in the depth of hostile territory. But dive bombers hardly reach such objects._

Again my point is that dive bomber crews needed very detailed training and plenty of experience to deliver an very specialised skill that was in decreasing demand. By 1945, where were dive-bombers being used in numbers other than in the Pacific? Aircraft like the Typhoon and IL-2 were carrying the Stuka's intended role as flying artillery _without any need for expensive crew training in dive-bombing_. 

Furthermore, when RAF's 2 Group wanted to down a bridge or other precision target, they didn't use dive bombers - they did it with level bombers attacking from very low level. The dive bomber skill was simply redundant by 1942-43, except on carriers where only dive bombers were small enough to be carried aboard.

_There is another way..._

The more complicated the device, the harder it is to teach someone to use it. The other way is, as I have said, to replace dive-bombers with with ground-attack aircraft using rockets, and medium bombers operating at very low level. There simply wasn't a need for dive-bombers (except on carriers) after 1943-42. That's why no more entered service...


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## gorizont (Jul 29, 2010)

BombTaxi said:


> The more complicated the device, the harder it is to teach someone to use it. The other way is, as I have said, to replace dive-bombers with with ground-attack aircraft using rockets, and medium bombers operating at very low level. There simply wasn't a need for dive-bombers (except on carriers) after 1943-42. That's why no more entered service...



The question of use of dive bombing is rather complicated so I answer you later dut this aspect I would make clear by now.
The principle is different. More complicated device is means of simplification of operator's acting.
In this case (jf dive -bombing) pilots "learned the subject for several years to became a good bombardirs, using simple reflector sight. they must get an ability to estimate all the corrections (wind, speed, dive angle etc) in short period of time using just visual observation. The task became more complex in case of attacking naval vessel. Such a target was in constant motion and moreover in the moment of attack could change its course and speed. Very difficalt tartget to achive a direct hit.
And using semi-automatic and fully-automatic sights for dive bombing made pilots training shorter and easier. And in battle it made a procedure of putting corrections easier and depended not on bombardir gift but on his skill to make proper manipulations in proper order.


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## Milosh (Jul 29, 2010)

davebender said:


> ??
> The Ju-88A was a "true blue" dive bomber complete with dive brakes and proper dive bomber sight.



From another board:

_Ju 88
wasn’t a dive bomber in same sense like Ju 87, Blackburn Skua or Douglas SBD Dauntless, A-4 was optimized for 60deg dive bombing, and it seems that earlier A-5 (in essence A-4 with earlier, less powerful engines) was optimized for 50 deg dives, which in fact means glide-bombing. In 43 Germans were modifying also A-4s for glide bombing, removing dive-brakes, calibrating automatic dive-bombing sight for shallower dive angles etc in order to use 88s as level bombers or glide-bomber which used 30 deg dives.

After dive brakes were removed Finns used 45 deg dives with their Ju 88A-4s._

That means the Spitfire was also a dive bomber as it dove at 60 deg.


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## parsifal (Jul 29, 2010)

In my opinion, there is no question that divebombing was a far accurate form of ordinance delivery. But it comes at a price. I think there are two major problems that takes the shine off the concept. The first is the vulnerability of the aircraftboth to fighters and flak. us navy tests in 1944 demonstrated that with vt fuses and good radar fc it took about 500 rounds to destroy db a/c. by comparison it was taking the germans around 16000 rounds to bring down a heavy bomber. against fighters it was a similar story. because a lot of weight had to devoted to airframe strength, d/b aircraft tended to be lightly armed and lacking in armour, and relatively speaking were poor performers. There were a number of reasons for this....level bombers could fly high whereas d/b had to generally drop to below 5000ft to releaease their ordinance. Whilst in the dive the aircraft was flying straight and to be accurate, slow. The combination of these factors made theem very vulnerable whilst attacking. And nearly useless against hevay targets like factories...... 

compare the performance of the ju88a-4 with something contemporary to. the a-4 with 2 x 1350 hp engines had a maximum speed of 292 mph. It had an empty range of 1696 miles (with any warloads it was a LOT less) . It could carry a max bombload of 5500 lbs, for short distances, but typically carried no more than 2000 lbs. As a divebombers it was only a qualified success. Against RN targets it was asessed as a moderate threat, the more lethal Ju87s were feared much more because of their steeper angle of attack. The Ju-88a-4 began to enter service in large numbers in 1939-40

I am tempted to make a comparison with the Mosquito, but this would be slightly unfair, since the Mossie was a slightly later and was more powerful than the Ju88. Perhaps a more reasonable comparison would be the LeO451. The French bomber had the following characteristics. It had a top speed of 317 mph, and a range with 1100 lbs of bombs of 1450 miles and a maximum bombload of 4500 lb, but usually it was 2200 lbs. The powerplant of the french bomber was 2 x 1140 hp radials 

The German bomber in 1940 carried a defensive armament of 5-7 mgs, whilst the French bomber carried a long range and hard hitting 20mm cannon and two mgs. In my opinion, the German aircraft paid a price for its divebombing ability in terms of its range, payload and performance, as compared to the French contemporary


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## davebender (Jul 29, 2010)

> German aircraft paid a price for its divebombing ability in terms of its range, payload and performance


Let's examine those items in detail. 1942 was the mid point for the European portion of WWII so I will use aircraft from that year.

*B-17E. *
Cost = $258,949 (per USAF statistical digest)
Bomb bay can hold up to 8,000 lbs. However 4,000 lbs was typical. Those 9 defensive machineguns plus gunners plus their equipment ate up the rest of the payload.
317 mph max speed.
Cruise speed with payload was 165 to 185 mph.
Bombing accuracy (during 1943). 16% of bombs fell within 1,000 feet of the aiming point.
Combat radius with 4,000 lb payload. ??
I could not find a combat radius (with normal 4,000 lb payload) for the B-17E. I would hazard a guess it was about 500 miles. Late war B-17s (F and G models) increased this with additional fuel tanks.

*Ju-88A4.* With 1,400 hp Jumo 211J engines.
Cost = $68,242 (170,605 marks during 1942. Assume 2.5 marks per dollar.)
.....You can purchase almost 4 Ju-88s for the price of 1 B-17E.

317 mph max speed.
.....Similiar to B-17E. However this figure makes little difference. Cruise speed with payload is what counts.

Up to 7,937 lbs of bombs can be carried (internal plus external). I assume about 4,000 lbs was typical.
.....Amazingly enough a typical Ju-88 payload was similiar in size to the much larger B-17E.

Cruise speed with payload was 211 to 239 mph.
.....About 50 mph faster then the B-17E. That makes the Ju-88 more difficult to intercept and to hit with ground based AA fire.

Bombing Accuracy. 50% of bombs fall within 50 meter circle under test conditions.
.....You won't achieve that level of accuracy under combat conditions. However it's readily apparent the Ju-88 was far more accurate then the B-17E. Perhaps 10 times as accurate.

It's worth noting that German bombers began receiving gyro stabilized bomb sights beginning during 1941. So a Ju-88 bombing during 1942 will probably use a 60 degree dive angle rather then a vertical dive. That increases Ju-88 survivability vs AA fire and places less stress on the airframe.

Combat radius with bomb load. About 400 miles.

What price did a 1942 Ju-88 pay in terms of performance compared to the American B-17? The Ju-88 was superior in every way except combat radius. And B-17E combat radius (with bomb load) wasn't that much better.

If you extend the comparison to 1943 then it's the B-17F vs the Me-410A dive bomber. The Me-410 has a much greater advantage in aircraft survivability while losing none of the of the advantages in bombing accuracy or aircraft production cost.


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## Milosh (Jul 29, 2010)

> It (Ju88 ) could carry a max bombload of 5500 lbs, for short distances, but *typically carried no more than 2000 lbs*.





> Up to 7,937 lbs of bombs can be carried (internal plus external). I assume about 4,000 lbs was typical.
> .....Amazingly enough a typical Ju-88 payload was similiar in size to the much larger B-17E.



When is 2000lb similar to 4000lb?

You can't compare cost as there are many other factors to consider, for instance, wages.


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## davebender (Jul 29, 2010)

> You can't compare cost as there are many other factors to consider, for instance, wages.


When I purchase a car I am interested in performance and cost. If I were to purchase an aircraft the same factors matter. I don't care what the production workers get paid.

However there are indeed other factors to consider. 
A B-17E requires a crew 3 or 4 times as large. Trained aircrew are probably more expensive then the aircraft itself.

The B-17 requires at least twice as much fuel per mission. Another expensive item. 

The B-17 is more expensive to maintain.

The larger B-17 requires a better equipped and therefore more expensive airfield from which to operate.


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## Shortround6 (Jul 29, 2010)

davebender said:


> Let's examine those items in detail. 1942 was the mid point for the European portion of WWII so I will use aircraft from that year.



Another biased comparison?


davebender said:


> *B-17E. *
> Cost = $258,949 (per USAF statistical digest)
> Bomb bay can hold up to 8,000 lbs. However 4,000 lbs was typical. Those 9 defensive machineguns plus gunners plus their equipment ate up the rest of the payload.
> 317 mph max speed.
> ...



Range with 4,000lbs was 2000miles, this turns into 600-700miles of radius?
Or try this:
http://www.zenoswarbirdvideos.com/Images/B-17/17TRC.pdf
Use the right had chart and cut bomb load to 4,000lbs. Seems like the speeds are a little better than you are claiming. 


davebender said:


> *Ju-88A4.* With 1,400 hp Jumo 211J engines.
> Cost = $68,242 (170,605 marks during 1942. Assume 2.5 marks per dollar.)
> .....You can purchase almost 4 Ju-88s for the price of 1 B-17E.



This one is so far off it is laughable. If you really believe this one I have a bridge in New York City I can sell you. Cheap to. o 
Calling it 3 1/2 Ju 88s to one B-17 just to be nice, Do you really believe that you can build 7 twelve cylinder liquid cooled engines for the actual cost of 4 nine cylinder air cooled engines? or 7 constant speed propellers?
How about the extra instruments and radios? or the 2000 sq ft of wing compared to the the single B-17s 1420 sq ft?
You have been told before about comparing prices of aircraft using currency exchange rates. You have to know if the currency exchange rates were artificially limited or not. You also have to know EXACTLY what the contract price covered. Some contracts stated XXX number of aircraft for YYY amount of Currency but Included varying percentages of spare parts. 


davebender said:


> 317 mph max speed.
> .....Similiar to B-17E. However this figure makes little difference. Cruise speed with payload is what counts.



True enough. except the JU-88's speed at max loaded weight was 269mph at 14,765ft. 


davebender said:


> Up to 7,937 lbs of bombs can be carried (internal plus external). I assume about 4,000 lbs was typical.
> .....Amazingly enough a typical Ju-88 payload was similiar in size to the much larger B-17E.



Where are you getting 7,937 lbs from aside from Wiki? and look at it for a minute. One book gives a max loaded weight of 30,865lbs for a JU-88A-4, with an empty equipped weight of 21,737lbs. subtract 800lbs for the 4 man crew and parachutes then subtract that 7,937lb bomb load and you are left with about 400lbs for fuel and oil. Even lowering the empty weight a few thousand pounds (and there is a difference between empty and empty equipped) doesn't leave all that much for fuel. Standard tankage was for 637Imp gallons(?) or 4777lbs of fuel. Guess we can see why the standard bomb load was closer to 4000lbs. Also on the A-4 model only ten 110lb fit inside. any additional bomb load went out side adding to the drag. 


davebender said:


> Cruise speed with payload was 211 to 239 mph.
> .....About 50 mph faster then the B-17E. That makes the Ju-88 more difficult to intercept and to hit with ground based AA fire.



I am not sure I am buying the cruise speed difference but go for it. 
You did forget to mention the difference in cruising heights though which also affects the accuracy of ground based AA fire. Shorter flight times to lower altitudes means less error in the time fuses and faster corrections of the fire control solution. the lower altitude also means that the planes are with in range of a given gun or battery for a longer period of time. 


davebender said:


> Bombing Accuracy. 50% of bombs fall within 50 meter circle under test conditions.
> .....You won't achieve that level of accuracy under combat conditions. However it's readily apparent the Ju-88 was far more accurate then the B-17E. Perhaps 10 times as accurate.



Ok, I will give you this one but then again the B-17s are not DIVING down to an altitude at which anything more powerful than Grandad's old WW I service revolver can shoot at it. 
Ok, that is an exaggeration but the B-17s are well above the range of 37-40mm guns let alone 20mm and smaller. What was the release hight needed to get the accuracy you claim? 




davebender said:


> Combat radius with bomb load. About 400 miles.
> 
> What price did a 1942 Ju-88 pay in terms of performance compared to the American B-17? The Ju-88 was superior in every way except combat radius. And B-17E combat radius (with bomb load) wasn't that much better.



Want to review that again.


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## Shortround6 (Jul 29, 2010)

davebender said:


> When I purchase a car I am interested in performance and cost. If I were to purchase an aircraft the same factors matter. I don't care what the production workers get paid.



you might want to consider if you can actually get the car for the price "advertised". 

Wages were controlled in both countries at the time. Price of the aircraft might or might not include "government furnished equipment. Or the Price "quoted" might be from adding in all the prices from the various suppliers.

Gee, Mr bender, here is your new car, please write one check to the frame/body maker. One check to the engine maker, one check to the rear axle/ drive shaft maker and a few more to the dashboard and radio makers. we may have forgotten one or two, they will bill you later. 
And by the way, car "A" comes with free parts, labor and oil changes for the next 5 years and care "B" doesn't. (spare parts) 

Still comparing performance and "cost"?

car "A" may be paying their workers more but with so many other variables how do you know that is why the cost is higher?


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## gorizont (Jul 29, 2010)

BombTaxi said:


> _Shtuka CEP was 30 metres. What was CEP for B-17? _
> 
> My point is that you don't need a 30m CEP unless you're going after a ship or a bridge. So for most targets, level bombing or shallow-dive attacks will do. In the specific case of a B-17, most targets were so big that getting the bombs into the correct postcode would do the job.



Above the battle field B-17 is almost useles moreover it is a danger to own troops. B-17 is almost useless in the case of attacking enemy ships of major classes in sea. Some success in attacking japanese vessels in sea B-17 achieved by skip-bombing and low -level bombing - and such patterns didn't allow to use the main mode of work for Norden - synchronous mode, because it couldn't work in this mode at alltitudes under 1000 metres. And in this case even destroyers became a hard nut to crack for Flying Fortress because of size of B-17 and its unperfect maneuverability. B-17 is useless for attacking concrete bunkers and so on.


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## Shortround6 (Jul 29, 2010)

Some thoughts on dive bombing;

1. It works really great on small high value targets like ships or bridges.
2. It brings the attacking planes into AA range of practically any gun that can be pointed skyward bigger than Granddads WW I service revolver. 
3. High value targets are often easy to spot. Dive bomber against ship means the dive bomber has to distinguish between ship and ocean. Not that hard to do even if you misidentify the ship (mistake DD for cruiser or oil tanker for carrier), Bridges too are not that hard to spot. Bombing factories is a bit harder. "was that 7 or 8 streets east of the RR tracks that the factory is located?" now count streets in the dive. and hope some joker hasn't painted a fake street on the factory roof. 
4. Small, high density high value targets are easier to hurt. A single 500-1000lb is going to mess up a ship pretty well. A single such bomb is going to stop production at a factory for how long? 
5. Combining #2 and #4. How many planes are you willing to trade for a destroyer or a cruiser or battleship?
How many planes are you willing to trade for the only supply bridge for miles over the river or the only retreat route for miles?
A destroyer can take around 2 years to build and is crewed by several hundred men. A big Cruiser can take 4 years to build and is crewed by a thousand men or more. Loosing even a couple of dozen planes might be considered a good trade.
Factories turned out to be much harder to actually destroy than most people thought. large machine tools almost need direct hits to destroy, a bomb hit even a few dozen yds away doesn't really bother them aside from perhaps cutting of their power. Blowing the roof off or all the windows out makes working conditions uncomfortable but aside from a few days clean up and perhaps destruction of work in progress may not affect next weeks or next moths production all that much. Please note that this reality was much different that what pre-war planners thought or even what some mid war planners thought. 
How many planes were you willing to loose to take a factory out for a few days or weeks. 
6. Fog or low clouds will screw up dive bombers every bit as much as level bombers, you can't hit what you can't see. 
7. Trying to dive bomb early war airfields won't give that much better results because thats what airfields were. Fields. a large expanse of grass with no runways. Fighters left the flight line after looking at the wind sock and taxied to the edge of the field away from were the wind was coming from and then took off into the wind. Landing was pretty much the same way in reverse. 
There is no runway to "cut" with a few well placed bombs. You need to take out the hangers/fuel (granted easier with dive bombers ) and then blanket the entire airfield with bomb craters. this last is harder to do with limited bomb capacity dive bombers. 

Each type has it's Place and use. Trying to build Strategic range dive bombers was a joke, although it didn't stop a few other air staffs from specifying it. Fortunately for the air forces involved the engineers managed to convince the air staff before the planes were actually built.


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## gorizont (Jul 29, 2010)

BombTaxi said:


> The other way is, as I have said, to replace dive-bombers with with ground-attack aircraft using rockets, and medium bombers operating at very low level. There simply wasn't a need for dive-bombers (except on carriers) after 1943-42. That's why no more entered service...



Dive-bombers for success needed airsuperiority for part which used this aircraft. Airsuperiority which could be temporary and local but it was urgently needed. Attack of dive - bombers isn't usually so surptising as attack of low-level or strafing aircrafts. 
Besides dive-bombing attack is more dangerous for attacking aircraft because of dive -bombers are highly vulnarable in a moment of recovering from dive. It can hardly be compared with danger to aircraft made a fast pass. 
But in comparison with a straifing or low-leveling aircrafts dive-bombers are far less vulnarable to AA fire in the moment of attack (final dive)- if we talking of period WWII. But It couldn't compansate a degree of vulnarability of dive-bombers at moment of recovering.
So germans were forced to change their tactic because of loss of superiority and the fact that AA defence became to the end of war much more powerful. 
So they used new devices to provide new tactic. Although using new bombing gyro-sights might help them to keep the high level of accuracy for dive-bombing despite of loss of many expirienced pilots or even to improve it.
Unguided rockets gave attack planes new oppotrunity - to launch a strike over the limits of effective fire of AA automatic guns. But they didn't have put a damage which could put a heavy bomb so in many cases they couldn't substitude heavy bombs.

As for germans you know that they started to use another methods and devices which let them attack out from zone of effective fire of AA guns against naval vessels - I mean Golden Zung and implementing guided weapon.


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## gorizont (Jul 29, 2010)

Shortround6 said:


> Some thoughts on dive bombing;
> 
> 1. It works really great on small high value targets like ships or bridges.
> 2. It brings the attacking planes into AA range of practically any gun that can be pointed skyward bigger than Granddads WW I service revolver.
> ...



Good post, Shortround6


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## Juha (Jul 29, 2010)

My 5c
IIRC average bombload for Ju 88A-4 was 1500kg (3300lb)
But was Ju 88 more accurate against ships than well trained levelbomber crews? During the attack in Dec 41 against Force Z IJNAF, besides the numerous torpedo hits by torpedo bombers which sank PoW and Repulse, 34 Japanese level bombers, most carrying one 500kg bomb, few carrying two 250kg bombs, got one 250kg hit on Repulse and one 500kg hit on PoW. PoW was hit when it was already badly crippled by torpedoes but Repulse was hit in undamaged conditions and while manoeuvring at high speed, and Repulse was manoeuvring very skilfully. IMHO Ju 88 wasn’t more effective in similar conditions. Of course most level bomber crews were not as well trained in anti-ship operations than those Japanese but for ex Ju 87s and Vals were clearly more effective against big warships than Ju 88 early in the war, later CAP and AA became too deadly for dive-bombers.

Juha


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## gjs238 (Jul 29, 2010)

Thought this was a comparison of dive bombers


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## Juha (Jul 29, 2010)

Hello Gorizont
There were problems during the Cobra bombing producing numerous US casualties, but I cannot recall were the culprits heavy or medium bombers but anyway the massive bombing effectively weakened German defence. During Goodwood the bombing was effective to certain depth of Germans defence, but because German defence had more depth than British were anticipated, south of the bombing zone British ran into grievous problems. Goodwood showed the strong and weak points of heavy bomber ground support. Heavy bombers could deliver stunning amount of destruction but they were very inflexible. In unexpected situation one could ask via radio dive-bombers or fighter bombers to try to eliminate the new danger, but heavy bombers could not be used in fluid situation.

Juha


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## davebender (Jul 29, 2010)

Any bomber needs air superiority for success. Unless you get lucky and the enemy are caught napping as happened at Pearl Harbor and Bari. However a low level attack improves the chances for achieving surprise. 

Cruising across enemy airspace at 20,000+ feet practically guarantees the enemy will know you are coming.


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## Juha (Jul 29, 2010)

Hello Davebender
now if one want to do some dive bombing one needs to approach at fairly high level.

Ju 88A bombers had 4 crewmembers, B-17E-G had 10 IIRC, not 3 or 4 times more.

Juha


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## JoeB (Jul 29, 2010)

Shortround6 said:


> Some thoughts on dive bombing;
> 
> 1. It works really great on small high value targets like ships or bridges.
> ...
> Each type has it's Place and use. Trying to build Strategic range dive bombers was a joke, although it didn't stop a few other air staffs from specifying it. Fortunately for the air forces involved the engineers managed to convince the air staff before the planes were actually built.


I second, good description of the different target aspects where dive or level bombing make more sense. I'd also add that even bridges sometimes turned out practically more suited to level bombing attack than dive as one type of interdiction target among a whole portfolio of others (railyards, supply depots, or 'suspected'* supply depots etc) gone after by the same force, for example US 9th AF medium bombers. The mediums had flexibility to strike, reasonably effectively, all the major types of fixed supply interdiction targets, and combat losses of 9th AF mediums to targets only defended by light AA were minimal (interception by German fighters was relatively unusual compared to what the heavy bombers faced; most 9th AF medium losses were to the limited number of heavy AA defended targets). Divebombers would have been suffered constant losses to light AA on what were effectively milk runs for the mediums (albeit level bombing mediums had to spend more fuel and bombs to get the job done v a point target like a bridge), and the targets defended by heavy AA would have had light AA also. So even besides truly strategic bombing, it's highly questionable IMO to suggest divebombers replace level bombers in a mission like 9th AF mediums in ETO.

Even v ships, in the Pacific, 5th AF mediums had tremendous success v ships with longer reach and less vulnerability to fighters (B-25 was relatively hard to catch, though not immune to interception, for most early to mid war Japanese fighter types down low, B-26 more so), using low altitude strafing/skip bombing. The A-24 (Army version of SBD) would be a questionable replacement for the B-25 in that role, against the particular types of ships attacked. Maybe against carriers the A-24 would be superior, but against merchant types and DD/escorts, armed as the Japanese ones were, the B-25 was highly effective with strafe/skip tactics. And again range was a major advantage v the particular types of divebombers which would have substituted, though a longer range divebomber could be built.

I think a fighter-divebomber like A-36 as subsitute for a fighter-bomber is a more serious question, and no the dive brakes on A-36's were not disused and finally wired shut, that's either a complete myth or was at most only the opinion of some units at certain times: others used the true dive bombing capability of that a/c to the fullest.

*IOW to add to your point about easy to spot high value targets being suitable for divebombers, w/ some targets like supply concentrations it was a hard for even good recon and intel to be sure the target really existed in the place the bombers were sent to hit, but they had to try those likely locations if they were ever to succeed in destroying some of the supplies. In these cases it was especially hard to justify losses of divebombers to light AA which might happen to be around anyway (Germans ca. 1944 had a it practically everywhere), as divebombers were demonstrating with their small CEP's v. the buildings the targeters had sent them after...but which didn't actually contain any military supplies.

Joe


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## Shortround6 (Jul 29, 2010)

davebender said:


> Cruising across enemy airspace at 20,000+ feet practically guarantees the enemy will know you are coming.



Dive bombers are not low level bombers.

They are mid level bombers that release at low altitude. 

At what altitude they start the dive?

Cruising across enemy airspace at at 10-15,000ft doesn't give much more of a surprise factor that flying at 20,000+ feet.

And cruising along at under 1000 ft and then climbing to 10,000ft+ in the target area tends to blow the surprise too.


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## davebender (Jul 29, 2010)

I agree.

My point is that practically all bombing conducted during the daytime requires fighter escort. A high cruise speed (with bomb load) helps some by limiting the amount of time over enemy territory but does not eliminate the chance for enemy interception.


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## parsifal (Jul 29, 2010)

Im glad you correcte your Post 35 in your post 39. Whilst it is generally true that air superiority is needed, in most situations, wher you have aircraft of exceptionally high performance or there is some technology or technique or enemy weakness being exploited, this does not apply.


In 1940, for many months, the germans found they could bomb British targets with near impunity, at night, despite the British having maintained control over their daytime airspace. The reason was because the British did not have a credible night fighter force at that time. In 1945 the US B-29s were able to bomb targets by day over Japan, because the Japanese did not have a day interceptor that could operate effectively at B-29 operating altitudes. From 1942 through to 1945, Mosquito intruder bombers operated in many situations with rrelative impunity because they could often use their speed to get them out of trouble. Sturmoviks were far from invulnerable, but they often operated over battlefields where the Luftweaffe theoretically possessed air superiority, using their numbers and the heavy armour that protected them to get them through and achieve the mission. The operation of the AR234s at the end of the war are another example. 

It is not valid to generalise about the vulnerability of bombers. There are many notable and strategically relevant exceptions to the statement. 

being e


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## VG-33 (Jul 30, 2010)

davebender said:


> I don't think Udet's hobby had anything to do with the German decision to emphasize dive bombing.


Living in a dictatorship system, it's always "better" to agree with your chief's opinion, whatever you think.



> HyperWar: The Battle of Britain--A German Perspective


Thanks for the link.
Anyway i have no doubt over the dive-bombing accuracy in general. But with some limits.



> Bombing Accuracy. 50% of bombs fall within 50 meter circle under test conditions.



It's what they *wish*, not what they *did*. According to Alfred Price and Michel Benichou works "Stuka, the shock!", Fana de l'aviation n° 406-411, you can multiply by 10 at least that distance in real combat conditions, with no remorses...



> Unlike the USA and Britain, the Luftwaffe conducted serious testing during the 1930s to determine bomber accuracy. Dive bombers were over 10 times as accurate as level bombers.



You mean they produced thousands of dive bombers without serious testing before? That's a scoop!
BTW, ten times *what accuracy*: aera, radius, cloud of points, Gauss curve, "sigma", mid geometric/harmonic distance from the target point etc...?




> That's why the Ju-88 was developed into a dive bomber and why RLM initially wanted the larger Do-217 and He-177 to dive bomb also. This was cutting edge technology during the 1930s. Nobody knew what the maximum size was for a dive bomber so they had to experiment. Dive bomber requirements for the Do-217 and He-177 were dropped after engineers determined it could not be made to work.



It's not only strengh problem. I suppose that the Pe-2 was a more than enough stressed dive-bomber, and much lighter and smaller to the Ju-88. But considering it's streamlined shape, relativly small airbrakes and airframe drag, in result of high speed and weight, it had to launch bombs above 1800m. The IAS being 720 km/h, 70° angle, the plane was sliding 800-900 meter down before *starting * recovering from the dive. So just at 1100-1200m hight after both pilot and autopilot efforts!!!

Imagine for an heavier and faster plane, saying 15 000 kg and 800km/h speed...
It makes what, minimal 3500-4000 m bomb dropping altitude. What accuracy do you hope with that?


I have 900-1000 m launch hight and 560 TAS values for the Ju-87, from at step dive. Sliding height loss was smaller considering inertia laws...

So: there-is a practical *height recovery *limit, except on dive- bombing with an Zeppelin-Staaken slow bomber, i don't see any solution for heavy and big planes.

On practical, from spanish campaign even the soviets caught the dive-bomber obsession. The I-15 and R-Zet generally was used for the task, at the end of the war.
But as you see, they were small and light planes, with "rotten" aerodynamics. *Good *divers were condamned to remain so...

Regards


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## VG-33 (Jul 30, 2010)

davebender said:


> ??
> The Ju-88A was a "true blue" dive bomber complete with dive brakes and proper dive bomber sight.




"True blue" means from the crush, Ju-88 was a modified fast bomber desigh. 
Do you think just by filling dive brakes and proper bomber sight on a Boeing 747 would make a dive bomber of it?


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## davebender (Jul 30, 2010)

> you can multiply by 10 at least that distance in real combat conditions


That would mean placing 50% of the bombs within a 500 meter circile. I suspect the average dive bomber pilot could do better.


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## gorizont (Jul 30, 2010)

VG-33 said:


> Thanks for the link.
> Anyway i have no doubt over the dive-bombing accuracy in general. But with some limits.
> 
> It's what they *wish*, not what they *did*. According to Alfred Price and Michel Benichou works "Stuka, the shock!", Fana de l'aviation n° 406-411, you can multiply by 10 at least that distance in real combat conditions, with no remorses...
> Regards



So 50% CEP was 500 metres. Interesting opinion. Let"s explain two examples of Shtuka acting from that point of view:
1) Do you remember how many hits recieved _Illustiuos_ at Malta?
2) And what about sinking HMS _Kelly_ and _Kashmire_ at Creet? 

I can't. Do you?


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## Juha (Jul 30, 2010)

Hello Gorizont
2 Gruppen of Stukas got 6 heavy hits on Illustrious and one light hit on Warspite, now that was IIRC best results they ever got against RN capital ships, IIRC in May 41 one Gruppe of Stukas got 1-2 heavy hits on Formitable and some near misses, they also damaged badly DD Numibian. But as I have wrote IMHO Ju 87 was a different animal than Ju 88, clearly more accurate.

Juha

Addition: Checked the Formitable case, 2 heavy hits on flight deck and one very damaging near miss, Numibian had its after turrets inoperative and lost its rudder but made it for Alexandria and was repaired, again battle ready in Oct 41. According the official record the hit on Numibian was achieved by a Ju 87 making a low level attack from behind.


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## gorizont (Jul 30, 2010)

Juha said:


> Hello Gorizont
> 2 Gruppen of Stukas got 6 heavy hits on Illustrious and one light hit on Warspite, now that was IIRC best results they ever got against RN capital ships, IIRC in May 41 one Gruppe of Stukas got 1-2 heavy hits on Formitable and some near misses, they also damaged badly DD Numibian. But as I have wrote IMHO Ju 87 was a different animal than Ju 88, clearly more accurate.
> 
> Juha



Hello Juha
It's my fault. I guessed for unknown reason that the claim was for all dive-bombers accuracy.


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## parsifal (Jul 30, 2010)

In the strike against Illustrious 10 Jan 1941 there were 43 Divebombers in the strike. These were all Ju-87s, the Ju88s did not participate in this strike. Not all the aircraft targetted the Illustrious, but contemporary account suggest about 30 attacked the carrier, with the remainder attacking mostly Warspite.

The Ju87s were carrying 250kg anti-personnel bombs and a single 1000lb SAP bomb. I think therefore that a total of either 86 or 129 bombs were dropped that day.

Of all the bombs dropped a total of 6 hit the Illustrious from this strike and a dud hit the Warspite. There were several additional hits from subsequent strikes.

The hit ratio of the Germans was therefore in the vicinity of 5-10%.

The Japanese 13 months later achieved bombing accuracies of around 80% with their Vals against the HMS Cornwall and Dorsetshire and the attacks against the Hermes.

Ju88s were not employed in the divebomber role on the 10 January. I believe also that as decent Italians torpedoes were obtained, Ju-88s tended to be used in the torpedo role, rather than the as divebombers. A good example of that are the attacks against the arctic convoys from April 1942 onward, where attacks by Ju-88s were almost exclusively with torpedoes.


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## Juha (Jul 30, 2010)

Hello Gorizont
You have made no mistakes, there are few different discussions alive in this thread, on dive-bombing in general and on Ju 88 in particular for ex. And you are very knowable on both.

Juha


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## gorizont (Jul 30, 2010)

parsifal said:


> In the strike against Illustrious 10 Jan 1941 there were 43 Divebombers in the strike. These were all Ju-87s, the Ju88s did not participate in this strike. Not all the aircraft targetted the Illustrious, but contemporary account suggest about 30 attacked the carrier, with the remainder attacking mostly Warspite.
> 
> The Ju87s were carrying 250kg anti-personnel bombs and a single 1000lb SAP bomb. I think therefore that a total of either 86 or 129 bombs were dropped that day.
> 
> ...



Not much but are you sure in your estimations? I guess You made a mistake in calculations.
1) In the attack of Illustrious at Malta on 10-th January 1941 Shtukas were loaded *one bomb each aircraft*. They were Ju-87B and in the case (distance etc) this mod of Shtuka couldn't bring to Malta more than one bomb of such calibers.
2) the ship was attacked by 18 Shtukas(formation - three groups, each consisted of two flights) from 43, participated in the strike.
3) so 6 direct hits from 18 dropped bombs is 30%. If we take into account two near misses - about 45%.

If we take into account that the strike had an opposition of 4 Fulmars, AA defence of ships and AA defence of the base, which consisted of about 90 AA batteries...



parsifal said:


> The Japanese 13 months later achieved bombing accuracies of around 80% with their Vals against the HMS Cornwall and Dorsetshire and the attacks against the Hermes.
> 
> Ju88s were not employed in the divebomber role on the 10 January. I believe also that as decent Italians torpedoes were obtained, Ju-88s tended to be used in the torpedo role, rather than the as divebombers. A good example of that are the attacks against the arctic convoys from April 1942 onward, where attacks by Ju-88s were almost exclusively with torpedoes.



Yes, I admit that I mistaked the claim. Ju-87 and Ju-88 are beasts of different sorts. I thought that VG-33 meant accuracy of all dive-bombers.


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## Juha (Jul 30, 2010)

On attacks on Illustrious in Jan 41
On Jan10 , first attack, 43 Ju 87s à one heavy bomb, 10 bombed the 2 battleships, Valiant and Warspite, all RN ships manoeuvring at high speed, CAP Fulmars decoyed at low level or out of ammo, the 4 just scrambled still too low, one 250kg glancing hit on Warspite, which detonates only partially. The rest of 87s attacked on Illustrious and got 6 hits and 3 near misses, Illustrious max speed reduced to 17kts and the rudder inoperative. 2nd attack, 13 87s, no hits, 3rd attack, 14 87s, one hit on Illustrious and one near miss on Valiant,. From 13 Jan on up to Jan 23 Illustrious was repeatedly attacked by Ju 87s and 88s while on naval dockyard in Valetta Harbour but these produced only one or two direct hit(s) and 2 near misses.

Juha


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## davebender (Jul 30, 2010)

How can we make that claim without historical Ju-88 dive bomber mission data for comparison purposes?


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## Lucky13 (Jul 30, 2010)

I know that us Swedes were early-ish out as well in the dive bombing field in 1931, how does the Northrop A-17, which we licensed as SAAB B-5 compare in this list? Tests were done at the airbase in my old hometown in Sweden.....


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## Juha (Jul 30, 2010)

Hello davebender
We? Now I and Gorizont can produce an impressive list of major warships sunk or crippled by Ju 87s, can You produce a list of major warships sunk or crippled by Ju 88s? Other than RN light cruiser Trinidad, which had earlier torpedoed herself (extreme cold had put one of its torpedoes run a circle and hit her instead of a German DD) and hastily patched at Murmansk, was hit on home run by a 250/500kg bomb dropped by a Ju 88 and the fire the bomb had started got out of hand and the cruiser had to be scuttled, one near miss had also blown away the hastily put patch over the opening produced by the torpedo hit.

Juha


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## Juha (Jul 30, 2010)

Hello Lucky
IIRC Swedes made also dive bombing tests with their Hawker Harts (B4?)

Juha


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## davebender (Jul 30, 2010)

Found this historical tidbit. Looks like a successful mission to me.

12 August 1940
12 Ju-88s dive bombed the British radar station at Ventnor (Isle of Wight) putting it out of action for 11 days.


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## BombTaxi (Jul 30, 2010)

davebender said:


> Found this historical tidbit. Looks like a successful mission to me.
> 
> 12 August 1940
> 12 Ju-88s dive bombed the British radar station at Ventnor (Isle of Wight) putting it out of action for 11 days.



Bear in mind Radar stations were not armoured or heavily revetted, and had large, fragile antenna projecting far above the ground. A few hits would put the station out of commission easily, and figher-bombers or level bomber could achieve exactly the same result. It's not the same as hitting a heavily armoured warship or a substantially-built steel bridge.


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## davebender (Jul 30, 2010)

> figher-bombers or level bomber could achieve exactly the same result


Then why didn't it happen?

12 bombers per radar station. 120 bombers for 10 radar stations. RAF Bomber Command and/or 8th U.S. Air Force could blow a massive hole in the German radar system using only a fraction of their total strength IF Lancasters and B-17s can bomb accurately enough to destroy a radar station using 12 aircraft.


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## Milosh (Jul 30, 2010)

On another board a guy is claiming the A-36 could have single-handedly won the war for the Allies by knocking out the German electric power generating stations in 1943. So far he has failed to explain how power stations more than 300miles from their base were to be attacked. Oh yes, he thinks the A-36s would not need escorts by flying low under the German radar.


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## DerAdlerIstGelandet (Jul 30, 2010)

Milosh said:


> On another board a guy is claiming the A-36 could have single-handedly won the war for the Allies by knocking out the German electric power generating stations in 1943. So far he has failed to explain how power stations more than 300miles from their base were to be attacked. Oh yes, he thinks the A-36s would not need escorts by flying low under the German radar.





What board was this?


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## Freebird (Jul 30, 2010)

DerAdlerIstGelandet said:


> What board was this?



Seasame Street forum?


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## parsifal (Jul 31, 2010)

davebender said:


> Then why didn't it happen?
> 
> 12 bombers per radar station. 120 bombers for 10 radar stations. RAF Bomber Command and/or 8th U.S. Air Force could blow a massive hole in the German radar system using only a fraction of their total strength IF Lancasters and B-17s can bomb accurately enough to destroy a radar station using 12 aircraft.



The attack on Ventnor was carried out by the Luftwaffes specialist intruder group (I forget the name) These guys were handpicked, highly trained and irreplaceable. They inflicted damage out of all proportion to their numbers. In June 1941, an advanced unit of just 30 bombers, Ju-88s operating as level bombers, managed to disable airfields containing nearly 1000 aircraft. 

If the Luftwaffe had been operating against an unprepred enemy, it might have been possible to knock out the radar stations by surprise attack. But against a forearned and prered defender specialist attacks are just going to get those highly trained specialists killed.

The same applies to the allies. They had specialist intruders, which were actually more accurate than the Ju-88, using blind bombing and specialised devices such as Oboe, they could, and did, knock out many German radar positions using pinpoint attacks. But the radar stations were difficiult targets, hard to locate and hard to hit. Same rules apply to the allies as were applicable to the Germans. Over-extension of the specialist resources will lead to their early loss.....and it takes years to replace these guys not months or days


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## Milosh (Jul 31, 2010)

DerAdlerIstGelandet said:


> What board was this?



Here is the thread.
Why the USAAF gave up on the A-36 in favour of the P-47. - Luftwaffe and Allied Air Forces Discussion Forum

While you are there, look at the other threads by tcolvin.


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## VG-33 (Jul 31, 2010)

davebender said:


> Any bomber needs air superiority for success. Unless you get lucky and the enemy are caught napping as happened at Pearl Harbor and Bari. However a low level attack improves the chances for achieving surprise.
> 
> Cruising across enemy airspace at 20,000+ feet practically guarantees the enemy will know you are coming.



Almost, not all.

Remember the SB-2 in spain, Do-17, DB-3 over china, Mossie in europe, B-29...


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## VG-33 (Jul 31, 2010)

parsifal said:


> _I am tempted to make a comparison with the Mosquito_, but this would be slightly unfair, since the Mossie was a slightly later and was more powerful than the Ju88. Perhaps a more reasonable comparison would be the LeO451. The French bomber had the following characteristics. It had a top speed of 317 mph, and a range with 1100 lbs of bombs of 1450 miles and a maximum bombload of 4500 lb, but usually it was 2200 lbs. The powerplant of the french bomber was 2 x 1140 hp radials



You can take either the Yak-4, or the Bloch MB 174 so, to remain in chronology respect.

Bloch MB.174 - Wikipédia

Yakovlev Yak-4 - Wikipédia

But it's still little unfair anyway. As the later Mossie, they are frankly smaller and lighter than the Ju-88. More faster two, this is not a surprise.

Regards


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## Juha (Jul 31, 2010)

Hello Davebender and Parsifal
Ventnor was knocked out by an ordinary Ju 88 unit, KG 51, not by the specialist fighter bomber unit EprGr 210.

Dave, check for D-Day, British fighter bombers knocked out tens of German radar stations just before D-Day. And historical tidbits are not enough for analyze, there is a case when a lonely B-17 sunk a Japanese DD in one high level run, did that make B-17 excellent anti-shipping a/c? Also they damaged badly IJN heavy cruiser Maya in Philippines in 41/42 etc.

Don't take me wrong, Ju 88 was excellent in glidebombing when equipped with Stuvi 5 sight and was excellent night fighter and good level bomber etc, but even if it had dive brakes it wasn't excellent dive-bomber, just too heavy to very deep dives. IMHO Soviet Pe-2 might well have been better in dive-bombing than Ju 88 even if it could carry clearly less bombs. Ju 88s have some successes, for ex when Hajo Herrmann destroyed much of Pireus when he hit an ammo ship, and the case of HMS Trinidad. But IMHO all widely used bombers made successful and unsuccessful attacks, so individual cases has not much weight as an evidence.

Juha


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## Juha (Jul 31, 2010)

IMHO there is too much fuss on heavy dive bombers. One can even argue that it was level bomber that made battleship obsolete. In 44 one didn’t need a hundred carrier torpedo- and dive bombers to sink a modern battleship. If it out of sea, sent a sqn of Do-217s armed with a Fritz-X per plane, if it in harbour, sent a sqn of Lanc with Tallboys. There was no way to armour a reasonable sized BB against those heavy bombs, so only chances BB had were enough fighters, smokescreen or in case of Fritz-X, ECM. Without them against well trained and courageous crews in bombers the BB’s changes were not good.

Juha


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## Lucky13 (Jul 31, 2010)

Hi Juha!

How's tricks in my old neighbouring country of Finland? To be honest, I completely forgot about the Swedish Air Force's Hawker Hart bombers....


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## VG-33 (Jul 31, 2010)

davebender said:


> That would mean placing 50% of the bombs within a 500 meter circile. I suspect the average dive bomber pilot could do better.



And what dou you suggest? That we should rather trust your opinion based on supposals and fantasy than qualified authors with conclusions based on hundred's cases studies?

Previously, i wrote " in real combat conditions". That mean errors, AA and fighter opposition, bad weather, stress, unknown crosswinds and topography...

For instance over Sedan, a french antitank battery near Anthée wood was attacked three times by Stukas. At morning there were so much AA oppostions, planes, artillery explosions, smoke than Stuka formation gets disabled and missed the mission. Round 12 o'clock, the wood was successfully attacked, burned and destroyed, but it was the neighbour's one. At evening Ju-87 took the trees shadow on the hill for the forest's edge ant attacked it.
Moreover the militar forests border is always 5-25m inside it. In result, no losses: 47mm canons were not hitted again. Position was later lost, but not due to Stuka's actions.
This is an example of concrete case.

Polygone exercice conditions are always easier and optimised. So the 1946th (real story) VVS bomb contest was won by a Li-2 (soviet DC-2) crew placing *all* his factice bombs inside a football game (soccer for you) central circle. That makes 9,15 m radius from a 3000m height. Without Norden sight of course, but with good optics, calibrated instruments, all by abaccuses and logarithmic slipstick calculation...

How far was it from a normal case, i let you imagine...


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## BombTaxi (Jul 31, 2010)

davebender said:


> Then why didn't it happen?
> 
> 12 bombers per radar station. 120 bombers for 10 radar stations. RAF Bomber Command and/or 8th U.S. Air Force could blow a massive hole in the German radar system using only a fraction of their total strength IF Lancasters and B-17s can bomb accurately enough to destroy a radar station using 12 aircraft.



Because Bomber Command and 8th AF were exclusively tasked with the strategic bombing campaign, and diverting heavies from city-busting would have been seen as an inexcusable waste of resources - possibly it would have been seen as overkill too, dropping massive bombloads on very fragile and easily-damaged targets. 2 Group, 9th AF and 2nd TAF were tasked with targets like German radar stations, and their mediums and fighter-bombers were involved in operations against that kind of target. Your question is disingenuous, as the issue at stake is strategic priorities and the tasking decisions made at very high command levels, NOT the actual capabilities of aircraft and crews


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## davebender (Jul 31, 2010)

I agree. We need more historical examples of Ju-88s being used to attack pinpoint targets. Then we can average the results to establish overall bombing accuracy. If only the knowledgable members of this forum would volunteer such information.....

Personally I don't care whether the aircraft attack was conducted at 90 degrees (i.e. classical dive bombing) or at an angle like 60 degrees. The point is the aircraft attacked at a steep angle to significantly improve bombing accuracy. 

BTW, does anyone know what attack angle was normally used by late war fighter-bombers like the Typhoon and Fw-190F? What sort of accuracy did they achieve using large bombs (at least 500 lbs)?


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## Juha (Jul 31, 2010)

Hello Davebender
in fact 90 deg dives were not common, 70-80 deg were the normal dive-bomber angles.

In ETO for Spits the dive angle was quoted at 60 degrees for the lead aircraft, with lesser angles for successive aircraft in the formation, for Typhoons, 60 degrees was the norm.

In MTO during high level dive bombing, Spits “near vertical”.

Juha


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## Shortround6 (Jul 31, 2010)

One might also want to check out where Ventnor was located, southeast east corner of the Isle of Wight.

Not much fighter cover.

I wonder what there were for AA defenses?

Dive bombing works pretty well against clearly defined targets (100 meter high tower?- 1/2 mile from the beach?) that are either undefended or poorly defended. 

Some other thoughts on dive bombing. 

1. Against "strategic" or fixed targets like factories. even barrage balloons are a useful part of the defense. The result in either higher release heights and lower accuracy or restrict approach or pull out areas. 
2. Going back to you can't hit what you can't see, dive bombing at night isn't going to work very well. 
2A. Smoke generators on the ground degrade the bombing accuracy of both types of bombers but they are going to degrade the dive bomber down to the level of the degraded level bombers. If the raid was planed on the basis of fewer planes needed because of the accuracy of the dive bombers the low density of the resulting attack pretty much guarantees failure. 
3. Dive bombing isn't needed for "fire raids" and incendiary bombs are 'low density' bombs, they require more volume for a given weight and require either larger aircraft to house them or create more drag for a given weight of bombs if carried externally. 
4. Sounds strange but dive bombers actually don't work well with armor piercing bombs. To pierce armor or concrete impact velocity is needed and the low release hight and restricted dive speed of the dive bomber combine to give lower impact velocities than than higher altitude releases do. 
5. Dive bombing worked well against targets were the approach was in undefended or 'neutral' territory. The ocean doesn't care who is flying over it and doesn't shoot at anybody. Try using dive bombers (of any size) to attack targets in Bristol, Birmingham or Manchester by flying over England in daylight and see what the results are. 
6. IF you KNOW your opponent is building, training and planning on using dive bombers as his primary means of bombing you can tailor the defense accordingly. Instead of large 3.7, 3.4 and 5.25in high altitude AA guns you can build more 3in AA guns and more 2pdr pom-poms and Bofors guns, plus use the previously mentioned barrage balloons and smoke generators. 
7. If your opponent had concentrated on dive bombers, especially large multi engine ones, they will be less efficient at some other types of bombing. The hundreds of pounds of extra airframe weight needed for the dive bombing mission will restrict either bomb load or range or both compared to a level bomber using the same engines.


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## Juha (Jul 31, 2010)

Hello Lucky
we are just recovering from a massive heat wave, back to normal 20+ deg C from 30+deg.

Juha


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## JoeB (Jul 31, 2010)

Juha said:


> Hello Davebender
> in fact 90 deg dives were not common, 70-80 deg were the normal dive-bomber angles.


IJN doctrine at the beginning of WWII was dive angle of 65 deg, though Allied observers usually estimated the dive angle of Type 99 Carrier Bombers ('Vals') in combat as less than that. As mentioned above that a/c demonstrated the highest hit rates ever observed in large scale dive bombing attacks v ships, v. the British CA's Dorsetshire and Cornwall April 5 1942, then Hermes and escort, plus transport and escort April 9. Both sides perceived a large %, much more than 1/2, of the bombs to have scored direct hits, though all targets sank quickly and no truly accurate count was possible as in case of a damaged ship. But I know of no other case on that scale (as opposed to some lone divebomber which scored a hit, 100%, on one ship) that showed that kind of hit rate estimated by both sides, none by other than the Japanese anyway. In prewar exercises by operational IJN units v moving target a high % of practice drops were hits, that was the standard.

Of course even more than in case of fighter combat, comparisons of divebomber achievements are comparisons of divebomber pilots rather than divebombers. So, a whole 'nother aspect of comparison of level bombers to divebombers would also be how much total training did it require to produce a top notch lead bombardier (on whose release everyone else would release) compared to a whole formation of top notch divebomber pilots each to place his bomb accurately.

In any case, if we find a single or few real combat cases where CEP was similar to what's quoted for tests, it doesn't show us much about what *average* combat results were compared to tests. It stands to reason that a test result will not be replicated on average in combat, but not necessarily that it could *never* be matched in combat. Even the 1942 IJN missed on plenty of inidividual drops, though ships targeted by more than a few of their divebombers relatively seldom escaped being hit. No stats to offer, but anecdotally reading books on the MTO campaigns, Axis divebombers, even German and Italian Ju-87's, seemed to come away empty more often in 1941-42 attacks on ships than the Japanese did in 1942, though hit plenty of ships cumulatively. Apropo to Shortround's comment about approach over the ocean v land, Axis divebombers going after British ships holed up in Malta harbor, with shore AA adding to the defense, even when not effectively intercepted by fighters prior to their drops, seemed to have a quite low hit rate, though again they did some damage cumulatively over lots of strikes.

Joe


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## davebender (Jul 31, 2010)

I'd rather not get into attacks on naval targets unless the ships were stationary. 

German dive bombers were designed to attack land based targets like bridges, bunkers and artillery positions. Later a few were adapted for naval attack but that was not their main purpose and most crews were not trained for naval attack missions. Sticking with land targets also allows a direct comparison with level bomber accuracy on similiar targets.


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## Juha (Aug 1, 2010)

Hello Davebender
first of all it is easier to get reliable info on ships, ships are clear cut cases, no problem what happened to them, on bridges there are at least some cases where it is not clear were they bought down by planes or by troops.

IMHO there was not principal difference between divebombers designed mainly to attack land or marine targets except perhaps range. And because GB was an important enemy of the Reich, after Dunkerque LW gave anti-shipping training its due attention. Fliegerkorps X, which came to Med in Jan 41 was an anti-shipping formation. And also level bombers attacked moving ships and among them were even less those specialized to anti-shipping work.

I admit that moving target always complicated comparison because the skilfulness of evasive manoeuvring varied but on the other hand there are easier access to reliable info and clear cut cases.

Juha


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## parsifal (Aug 1, 2010)

There were some divebombers that anecdotally appear less accurate than the wst rate divebombers. For example I have read the French LN401 was not as good as the Ju87, because it was not as stable in its flight characteristics. It was never able to demonstrate its true capabilities but neither was it an aircraft that appeared to shine in its brief service. Another similar aircraft would have to be the Blackburn Skua, not a particulalry good example of a divebomber. 

The Ju-87 has to rate as one of the best divebombers ever built. It was slow and stable, and while this made it vulnerable, it also meant that it could hit targets with pinpoint accuracy. If the Japanese had been equipped with Stukas instead of Vals, I dont think it would have made any difference to accuracy. So long as the platform met certain criteria, it was the pilot training and what they had been trained for that made the difference, not the aircraft. The Japanese were specialists in destroying ships, relatively few european Axis aircrew were so trained.

The Ju-88 was faster and more survivable, but it also had a shallower and faster divespeed, and this made it less potent i the role, at least at sea. And on land I still believe it was the Ju-87 that was viewed as the pinpoint attack weapon of choice


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## davebender (Aug 1, 2010)

> principal difference between divebombers designed mainly to attack land or marine targets


Aircrew training is the difference. The Luftwaffe did not assume responsibility for aerial maritime attacks until January 1942. Prior to then only a select few Ju-87 and Ju-88 aircrew were trained for naval attack. You cannot expect German aircrew to be good at sinking ships if they have not been trained for that mission. However I suspect they were real good at knocking out bridges, bunkers and artillery emplacements. They had to be as the early war Heer was short of both artillery and artillery ammunition, especially compared to next door France.

German Torpedo Bombers? What Were they?


> In January 1942, the Luftwaffe’s demands for the centralization and control of all German and Italian torpedo development were finally granted. Colonel Martin Harlinghausen was appointed as the head of all Luftwaffe torpedo development, supply, training and operational organizations, with the TorpedoTraining School established at Grosseto in Italy. During the early months of 1942, I/KG 26 underwent torpedo conversion-courses, lasting between three and four weeks. The Gruppe’s He-111H-6’s could carry two torpedoes slung on racks beneath the belly; the standard torpedoes used were the German LT F5 and LT F5W, both of 450-mm caliber, with the latter based on the Italian model made by Silurificio Whitehead di Fiume.
> 
> While I/KG 26 underwent conversion at Grosseto, its future and the bases from which it would operate had already been decided. Luftflotte V, based in Norway and Finland, needed additional bomber support to interdict Allied convoys on the Murmansk/Archangelsk route. In March, Göring ordered Luftflotte V to collaborate with the aerial reconnaissance units of the Kreigsmarine and to attack the convoys when they came into range, and also to shift bomber forces from the Finnish front to accomplish this task. Within I/KG 26, based at Banak and Bardufoss, there were 12 crews available for torpedo operations with the Heinkel He 111H-6 planes.


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## Juha (Aug 1, 2010)

Hello Davebender
Quote:” The Luftwaffe did not assume responsibility for aerial maritime attacks until January 1942”

Well, who was responsible for aerial maritime attacks before that? Torpedo wasn’t the only anti-shipping weapon. IIRC even if Ju 87s was fairly effective during Norwegian campaign and during Dunkerque evacuation it was decided to give more anti-shipping training to Stuka crews, and as I wrote X Fliegerkorps was LW’s anti-shipping unit, had been since late 39 IIRC, firstly as 10. Fliegerdivision. Also IIRC there was also 9. Fliegerdivision/ IX Fliegerkorps. And it was Ju 87s and 88s of those units which carried out most of attacks against RN early in the war with He 111s of KG 26, also a unit belonging to X Fliegerkorps and of course Fw 200s of I/KG 40 which might well have been part of 9. Fliegerdivision/ IX Fliegerkorps.

Juha


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## davebender (Aug 1, 2010)

> who was responsible for aerial maritime attacks before that?


The German Navy. Unfortunately (for Germany) Admiral Raeder was not a fan of either aircraft or submarines. So German maritime attack aircraft programs received little funding until after the Luftwaffe assumed control during 1942. By then it was almost too late to matter as the Med and Altantic coastal regions were covered by swarms of British fighter aircraft.


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## Juha (Aug 1, 2010)

I disagree, what is your source? Now the planes of for ex X Fliegerkorps, which attacked RN ships in 39 and 41 belonged to LW so LW's anti-shipping units attacked already in late 39 against RN. Kriegsmarine tried to monopolice torpedo but as I wrote that wasn't only anti-shipping weapon. 40-41 many LW units operated against ships around UK etc.

Juha


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## JoeB (Aug 1, 2010)

Also the basic distinction between hitting a ship and hitting a bridge or tank or bunker is false. If you can't hit a ship, you can't hit a bunker. The fact that the ship is moving is a relatively small part of this issue, getting the bomb to fall where you want it to (correcting for eg wind) to the degree of hitting a ship size target, that's the big part of the issue. LW divebombers were pretty accurate, therefore acceptably effective from German POV, distressingly effective from British and French POV, even off Norway and latter stages of the Battle of France.

The prime of Japanese divebomber pilots could also hit small (er than a ship) stationary targets on land quite well compared to others, as they sometimes demostrated in the early months of the war. Mainly good divebombing was a single skill set, not mainly a different skill set between ship and other point target attack.

But, some targets like well dug in gun emplacements were quite difficult for even divebombers to neutralize, as was also demonstrated by good divebombers of various countries. An example which comes to mind is the USN divebombers at Casablanca in November 1942. The same SBD unit, VS-41, had pretty good (not best ever type results like the Type 99's in Ceylon area anti-ship attacks, but still pretty good) results v French ships, moving and stationary, but just couldn't get bombs to fall within the actual emplacements of the El Hank battery, which is what it would take to destroy such a position. The battery suffered limited personnel casualties, little material damage, in a few days of attacks. Photo's show the area of the battery covered with craters (from USN ships' shell as well as bombs), mostly close, but not close enough. Such a target might be more productively plastered by a larger number of medium or heavy level bombers and get some direct hits by law of large numbers, though a much bigger number of bombs, assuming you had such forces. Or, perhaps the absolute best divebomber units could have gotten direct hits on those gun pits, but again the issue arises of producing, and *reproducing* this level of performance during a war. Divebombers often suffered heavy crew losses which needed to be replaced; and in USN case and other cases, an air arm was often expanding at an enormous pace to meet the needs of the war for good (not absolute best) divebomber units.

Joe


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## renrich (Aug 1, 2010)

One of the factors which helped the LW divebombers, (and the Japanese also) against British ships was that the British shipborne AA was not very effective.


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## davebender (Aug 1, 2010)

Something definately went wrong at Bari during December 1943. I believe the RN was responsible for the defense of that port.


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## RCAFson (Aug 2, 2010)

davebender said:


> Something definately went wrong at Bari during December 1943. I believe the RN was responsible for the defense of that port.



I've read various accounts of the Bari disaster, and none of them mention that any RN warships were in the port, except for a depot ship. The lack of a fighter defence seems to be the primary lapse in Allied defence planning.


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## Shortround6 (Aug 2, 2010)

I am not sure what the Bari raid has to do with dive bombing.

Was dive bombing actually used in the raid or is this brought up because the Ju-88A-4s used in the raid were capable of dive bombing?

Bari was headquarters for the US 15th Air Force but defense of the port was in the hands of the British army.

I am not sure what the defense of Bari with shore guns has to do with the RN pitiful ship mounted AA defense in the beginning of the war.


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## parsifal (Aug 2, 2010)

Bari is more a red herring than that. It was a disaster, to be sure, and full credit to the high standards of Luftwaffe planning that went into it. But the damage that arose was because of the target ships expploding, full of ammunition as they were, and not the inherent lethality of the aircraft attacking them. The attack force was well led, and the raid well executed, but it was very lucky just the same


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## davebender (Aug 2, 2010)

> defense of the port was in the hands of the British army


Does that include coast defense guns and AA guns surrounding the harbor, protective minefields, PT boats and minesweepers operating in the shipping channel, radar systems located in the port area and operating on harbor craft like PT boats etc?


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## Shortround6 (Aug 2, 2010)

davebender said:


> Does that include coast defense guns and AA guns surrounding the harbor, protective minefields, PT boats and minesweepers operating in the shipping channel, radar systems located in the port area and operating on harbor craft like PT boats etc?




Care to tell us just where you are getting this account from?

It seems widely at variance with this account.

World War II: German Raid on Bari HistoryNet

This from top of page two. 

British army Captain A.B. Jenks, who was responsible for the port's defense, knew that preparations for an attack were woefully inadequate.

As for the PT boats (in British service MTBs) try this account:

BBC - WW2 People's War - Bari Raid, 2nd December 1943

Care to detail the coast defense guns for us?

The Italians had surrendered almost 3 months before, German Naval strength in the Adriatic was hardly up to gun bombardment raids.


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## renrich (Aug 2, 2010)

Although Bari may not be a good example of the poor results obtained by RN ship's AA, it is well known that the RN suffered from very poor director fire from AA. The best example my be the Repulse and POW where the Japanese VBs and VTs were almost immune, although the IJN in the raid on Ceylon and the sinking of two CAs and a CV suffered little from AA.


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## Shortround6 (Aug 2, 2010)

There is no doubt that the RN suffered from a lack of AA capability for most of the war.

Not enough big AA guns, Director control not good enough and light AA almost non-existent at times. 
A pair of quadruple .5 MGs as the only AA guns for a Destroyer?

Lack of guns and director control has little to do with Bari as Renrich has said although it does help to explain some of the success early dive bombers had against the Royal Navy. A good bit of the Ssuccess is due to the crews of the dive bombers but better AA would have caused both more misses and a higher attrition rate among the dive bombers.


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## RCAFson (Aug 2, 2010)

renrich said:


> Although Bari may not be a good example of the poor results obtained by RN ship's AA, it is well known that the RN suffered from very poor director fire from AA. The best example my be the Repulse and POW where the Japanese VBs and VTs were almost immune, although the IJN in the raid on Ceylon and the sinking of two CAs and a CV suffered little from AA.



The RN seemed to do pretty good against PQ-18 where AA shot down over 30 Luftwaffe aircraft out of about 260 sorties flown against it, and during the Malta Convoys. 

http://www.ibiblio.org/hyperwar/UN/UK/LondonGazette/39041.pdf

Isolated ships could be overwhelmed, but when a balanced force defended a convoy, for example, they certainly made the Luftwaffe or Italian Airforce pay a stiff price.


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## RCAFson (Aug 2, 2010)

Shortround6 said:


> A pair of quadruple .5 MGs as the only AA guns for a Destroyer?



Starting with the Tribal class RN destroyers actually had quite a heavy close range AA armament compared to their contemporaries. In 1939 a typical USN DD only had 4 x .5" MGs, while a Tribal or a J class DD had a quad pom-pom and 2 quad .5". 

Tribal class destroyer (1936) - Wikipedia, the free encyclopedia


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## BombTaxi (Aug 2, 2010)

The RN suffered from substandard AA direction equipment for most of the war. The armament itself was relatively heavy, but it needed to be when it was so poorly guided. 

And Dave, if the LW 'wasn't responsible' for shipping attacks prior to 1942, who was operating the aircraft that attacked coastal traffic during the Kanalkampf, or that attacked the evacuation fleet during Operation Dynamo, or attacked Mediterranean convoys, or indeed, who controlled the Fw200s that hounded the Atlantic convoys and required the introduction of CAM ships, and ultimately, CVEs?

Furthermore, excluding shipping attacks from your assessment of divebomber effectiveness simply shows a lack of faith in your own argument, as such data will show that skilled crews (Americans late in the war, for example), sink far more ships than rookie crews (IJN late in the war, for example). It will therefore become apparent, as several posters have mentioned, that crew training is what made divebombers accurate, rather than any inherent advantage in the airframe designs themselves.


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## RCAFson (Aug 2, 2010)

BombTaxi said:


> The RN suffered from substandard AA direction equipment for most of the war.



OK, then which navy had "standard" or "above standard" AA direction equipment in WW2?

How many of those slow Swordfish did Bismarck shoot down? Was German navy AA above standard?

Was Italian navy AA above standard?

How about the IJN? The RN had AA fire-control radar in 1940, and the IJN never developed AA FC radar. and neither did any other Axis navy, AFAIK.

The USN certainly had massive AA armaments in 1945, and had VT ammo from Jan 1943 onward, but the RN seems to compare well with other Navys in the early war period.


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## BombTaxi (Aug 2, 2010)

RCAFson said:


> OK, then which navy had "standard" or "above standard" AA direction equipment in WW2?
> 
> How many of those slow Swordfish did Bismarck shoot down? Was German navy AA above standard?
> 
> ...



I'm happy to debate this in detail in a more appropriate place, but the short story is that the HACS system used by the RN early in the war was not fully tachymetric, and therefore did not provide accurate firing solutions. In 1937, a Queen Bee drone circled the Home Fleet for two and a half hours, constantly under fire from HACS equipped ships. Not a single hit was scored. The following year, the Admiralty's own Director of Research described HACS as a 'menace to the service'. Air-search radar was experimentally fitted to HMS Rodney and HMS Sheffield for the first time in 1939. The same year, the Germans deployed Seetakt operationally, and the Americans began operational deployment of the XAF air-warning/gunnery set. HACS proved woefully inadequate in the Med, where the strikes that crippled HMS Illustrious and HMS Gloucester, and led to the scuttling of HMS Southampton, were pulled off by small groups of divebombers evading the fighter screen and penetrating the HACS-controlled screen with impunity. It isn't pretty reading, but most of RN's surface-to-air and surface-to-surface fire-control gear was obsolescent or ineffective in 1939, mainly due to Admiralty cost-cutting and a pervasive failure at very high levels to understand the threat posed by aircraft to warships. After all, a department was not set up to study AA gunnery within the RN until *1935*

My source for all of the above is Corelli Barnett's _Engage The Enemy More Closely: The Royal Navy In The Scond World War_, pp.46-49 and _passim_, and I suggest giving it a read to understand the technological deficit with which the RN and FAA entered WWII.


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## JoeB (Aug 2, 2010)

Ship AA claims v a/c would be a case even more unwise than aerial claims in which to conclude anything from one side's accounts. Also, torpedo bombers from even early in WWII had greater vulnerability to AA than divebombers or level bombers, a tradeoff for their ability to 'punch holes which let in water, not air'. 

I agree the basic fact is that all navies underestimated the air threat *in practice* prior to WWII. On the basis of design and potential one could debate whether the USN was ahead of the game in fitting true dual purpose directors and armament to DD's, and had arguably better directors and heavy AA guns. But as a practical matter the USN wasn't particularly ready when the US entered the war, in either heavy AA training or condition of equipment (lots of bad 5" AA ammo/fuzes early on, for example), and wasn't up to speed even in time fuze heavy heavy capability until the 2nd half of 1942. Then, pre-VT heavy AA of any kind had trouble dealing with divebombers, and a lot of kills by ships v. torpedo bombers and divebombers were scored by light AA acting as 'revenge' weapon after the plane dropped its weapon (though, it was hoped the AA could distract their aim before they dropped). And the USN didn't have systematically better light AA fits in 1942 than other navies, started out probably less adequate on the whole than RN, which again had been at war for 2+ years.

However as far as assessing results of divebombers relative to the AA threat, if we consider Med actions of 1941-42 v those in Pacific in 1942, v Allied navies, we're talking roughly similar AA capabilities across the Allies navies, broadly speaking, though again the USN was rapidly coming up to speed from unprepared situation in Dec 41. But in no case in 1941-42 are we talking about cases similar to British and French DD's in 1940, which could just send up a few MG tracers to distract a divebomber pilot; were basically counting on dodging the bomb. There is IOW a more serious problem comparing the effectiveness of divebombers ca 1940 v ca. 1942, even before the very heavy AA armaments of 43-45.

Joe


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## RCAFson (Aug 2, 2010)

BombTaxi said:


> I'm happy to debate this in detail in a more appropriate place, but the short story is that the HACS system used by the RN early in the war was not fully tachymetric, and therefore did not provide accurate firing solutions. In 1937, a Queen Bee drone circled the Home Fleet for two and a half hours, constantly under fire from HACS equipped ships. Not a single hit was scored. The following year, the Admiralty's own Director of Research described HACS as a 'menace to the service'. Air-search radar was experimentally fitted to HMS Rodney and HMS Sheffield for the first time in 1939. The same year, the Germans deployed Seetakt operationally, and the Americans began operational deployment of the XAF air-warning/gunnery set. HACS proved woefully inadequate in the Med, where the strikes that crippled HMS Illustrious and HMS Gloucester, and led to the scuttling of HMS Southampton, were pulled off by small groups of divebombers evading the fighter screen and penetrating the HACS-controlled screen with impunity. It isn't pretty reading, but most of RN's surface-to-air and surface-to-surface fire-control gear was obsolescent or ineffective in 1939, mainly due to Admiralty cost-cutting and a pervasive failure at very high levels to understand the threat posed by aircraft to warships. After all, a department was not set up to study AA gunnery within the RN until *1935*
> 
> My source for all of the above is Corelli Barnett's _Engage The Enemy More Closely: The Royal Navy In The Scond World War_, pp.46-49 and _passim_, and I suggest giving it a read to understand the technological deficit with which the RN and FAA entered WWII.



I did a lot of research on RN/RCN AA because a previous thread regarding the Fw200 versus convoys, piqued my interest. I thought it rather interesting that HMCS Prince Robert, an RCN AA cruiser could fend off multiple Luftwaffe guided missile attacks:
http://www.ww2aircraft.net/forum/aviation/fw-200-vs-allied-convoys-25548-3.html#post696173

The RN conducted type 79 radar sea trials in April 1938 and began operational use in Oct 1938 aboard Rodney and the cruiser Sheffield. 
Seetakt was a surface search/gunnery radar and had no AA capability. The first USN AA radar, the Mk 4 was developed with RN help, and conducted *trials* in Sept 1941.
The first RN FC AA radar was type 280 and it went to sea in 1939 aboard the AA cruiser Carlisle. It was based upon the British Army GL radar and featured a ranging panel that could provide range accuracy of +/- 25 yds against aerial and surface targets. This ranging panel was then fitted to most radars, including the type 279 aboard Fiji and most other ships with type 279 or 281 radar. Gloucester and Fiji were sunk by aerial attack in May 1941, but only after they ran out of AA ammo. This ranging panel could feed radar ranges directly to the FC computer. 

By Sept 28 1941, 31 RN destroyers, 5 sloops and 20 larger ships had type 285 radar, which was a dedicated AA FC radar. AFAIK, no other navy had operational AA FC radar at that date. By the end of 1941 46 RN ships, larger than destroyers had type 279/280/281 radars, most with surface/AA ranging panels.

The RN used a special low HE capacity shell when shooting at the Queen Bee, yet shot down 6 in one month in early 1936, when they used them, presumably, in a manner more closely emulating actual attack runs. WW2 AA systems always assumed straight line flight and could not "predict" the path of a circling aircraft. By 1940, the RN was also adding the Gyro Rate Unit to the HACS, which converted it to tachymetric operation. IN 1940 the RN began to introduce the Mk IV Pom-Pom director, which was fully tachymetric and included a Gyro Rate Unit. The Pom-pom director and GRU was very similar to the USN Mk51 director which used the Mk14 gyro gun sight. 

Sources:
Radar at Sea, Howse 
Naval Weapons of WW2, Campell

HACS - Wikipedia, the free encyclopedia
Gyro Rate Unit - Wikipedia, the free encyclopedia
Pom-Pom Director - Wikipedia, the free encyclopedia
HMS Fiji (58) - Wikipedia, the free encyclopedia


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## Juha (Aug 2, 2010)

There have been many arguments on HACS and my 2 cent is that it was rather useless first, especially against dive bombers but it was improved over time, IIRC there was 4 marks and III, III* and IV began to be at the level of best USN and IJN high-angle directors and already Mk II or Mk II* was clearly better than the earlier version and passable against targets which changed their speed or altitude, which had been the worst problem of original HACS. But UK and Japan were unable to produce sufficient numbers of their best high-angle directors so many ships had to try to cope with second rate directors.

Juha


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## parsifal (Aug 3, 2010)

I would just point out that the primary mission for AA is not to shoot down enemy aircraft. That is primarily the responsibility of fighter aircraft. Flaks primary purpose is to throw the attacking aircraft off their aim, and to disrupt attacks. It does this by volume of fire, and by getting gunfire as close to the target as possible, not necessarily hiting it. Damaging an aircraft and forcing it to abort, or alternatively to so buffet the aircraft as to throw it off its aim is as good as shooting the aircraft down. 

The numbers of airacraft damaged and forced to abort (either by that damage or simply by scaring the pants out of the attacking aircrew) is estimated to have affected close to 1/3 the bombers attacking Schweinfurt in 1943. There is no reason to suggest that it did not affect other nationalities to any lesser extent. In this regard, one has only to look at such operations as Pedestal to rapidly realize that British seaborne ack ack was eminantly successful in carrying out its primary mission.

Whilst there is no doubt in my mind that US fire control was better designed than its British counterparts, against such an intractable enemy as the japanese this did not count for much. During 1944-5, once Kamikazes started to be used, the USN had a great deal of trouble in breaking up Japanese Kamikaze strikes in the accepted way. A damaged Kamikaze is as dangerous as an undamaged one, and unfortunately for the allies, a damaged Kamikaze is unlikely to abort its mission. Whilst the suicide attacks by the Japanese tended to increase the kill rates of USN flak, it also meant as an attack method it was harder to stop. This was why the USN clamoured for the introduction of the 6" AA gun....so that a single shot had the capability to bring down a Kamikaze with a single hit.

I am unaware that the RN in the Pacific had any more or any less success in its flak defences as the US. This leads me to suspect that for practical purposes in 1945 at least that the British flak was no better and no worse than its USN counterparts, in the context of defeating the Japanese suicide attacks.


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## renrich (Aug 3, 2010)

Quite a number of years ago, I read a book written by a British admiral, (I think he was an admiral but I am certain he was a RN officer) that was a very detailed account of the RN in WW2. He mentioned a number of times how inadequate the RN AA was because of the apparatus for sighting or directing the fire. I wish I could remember the book's name but it was a library book and too long ago for me to remember. I have always marveled at the KGV class's "countersunk" 5.25 inch secondary armament. I thought it was an elegant engineering solution and made the gun houses less vulnerable but it apparently did not make them more effective against EA.

The following certainly is not necessarily proof of anything but in WW2, according to Janes 1944-45, the RN lost 30 cruisers and 12 of those were lost to enemy air action. The US lost ten cruisers and one of those was lost to air action.

The RN lost two capital ships at sea to air action and the US lost none at sea to air action although that comparison certainly is probably not as valid because I can think of no US capital ships exposed to air action without having some CAP protection.

Arguably the Japanese anti shipping aircraft strikes were more effective than the Axis air strikes in the ETO. The Germans had torpedo problems early in the war, almost as badly as the US. The Japanese ship launched and aircraft launched torpedos were pretty reliable.

I don't believe that judging the effectiveness of AA fire based on comparing results against dive and torpedo bombers and those results against Kamikazes makes much sense. It is much easier to hit a target with one's plane than it is to score hits with bombs or torpedos.


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## Nikademus (Aug 3, 2010)

parsifal said:


> I would just point out that the primary mission for AA is not to shoot down enemy aircraft. That is primarily the responsibility of fighter aircraft. Flaks primary purpose is to throw the attacking aircraft off their aim, and to disrupt attacks.



Actually shooting down aircraft is a primary mission of both AA and Fighter aircraft. The other facets mentioned are also equally important to both types of weapon systems. The problem with judging AA is that too often, people, including the professionals at the time, tend to fixate on outright kills because its a statistic that can easily and quickly be grasped as a measure of "success". This was a major problem for Germany during the Bombing campaign on their cities. The guys in charge on the ground wern't interested in how many planes were damaged, or driven off, or made to make inaccurate runs..they only wanted to know one thing. "how many of the enemy did you shoot down??!!" This helped fuel arguments on downplaying flak development in favor of more fighters. Ironically in the case of Germany, postwar analysis indicated that flak actually ended up shooting down more enemy planes than the Jagdwaffe....even when not factoring in damaged planes later picked off by fighters. 

The same tunnel vision impacts CAP analysis at times too. The Illustrious Blitz is a good capsule on that. Malta's AA and CAP defenders didn't score much during the "Blitz" and that overshadowed their primary acomplishment, which was disrupting the attacks enough that only a few hits were scored.


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## RCAFson (Aug 3, 2010)

renrich said:


> The following certainly is not necessarily proof of anything but in WW2, according to Janes 1944-45, the RN lost 30 cruisers and 12 of those were lost to enemy air action. The US lost ten cruisers and one of those was lost to air action.
> 
> The RN lost two capital ships at sea to air action and the US lost none at sea to air action although that comparison certainly is probably not as valid because I can think of no US capital ships exposed to air action without having some CAP protection.
> 
> ...



The IAF had a very effective TB from the start in the SM-79 and they had effective torpedoes as well. 

The RN faced several problems which the USN, largely, did not have to deal with, mainly that the RN had to supply, protect, and then withdraw large numbers of troops from areas completely dominated by enemy airforces. Many of the RN ships were actually scuttled, rather than sunk outright, but they had no choice but to do so because they were typically well within reach of enemy airforces and devoid of air cover themselves. Malta was a thorn in the side of the Axis, but was also a major headache for the RN, which regularly had to face hundreds of Axis aircraft while trying to run convoys through to the island. The number of sorties that the Axis flew against the RN is also really staggering, when you start to add it all up.


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## Kurfürst (Aug 3, 2010)

Nikademus said:


> This helped fuel arguments on downplaying flak development in favor of more fighters. Ironically in the case of Germany, postwar analysis indicated that flak actually ended up shooting down more enemy planes than the Jagdwaffe....even when not factoring in damaged planes later picked off by fighters.



That's true but don't forget the cost analysis - only a couple of hundred fighters were employed during the most successfull period of the RV (1943), vs literally thousends of Flak batteries scattered all over Germany, most of which could simply not fight the threat due to its immobility, and were damned to a passive role. They were important part of the defense, being always there, yes, and much if not most of the circa million personnel serving them were unfit for normal military duties (teenager kids, Hiwis and the like) but IMHO fighters overall were considerably more cost effective - though in fairness the fighters themselves required a fairly extensive logistic network, ie. fuel, ground crew. Altough the latter is true for the Flak as well, namely, they expended huge amounts of ammunition.


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## JoeB (Aug 3, 2010)

If it could be possible to compare Med and Pacific in a non national-dick-measuring US v British way (fat chance! ) the only reasonable conclusion would be that the two situations differed too much to make easy and direct comparisons of the AA effectiveness of the ships. But the Brit uber-alles type posters on the internet with 'far bigger air threat in Med' are really being quite ridiculous, as shown by the RN's own operations early in the Pacific War. There were a larger number of *engagements* between Axis a/c and Allied ships in Med througth whole of 1940-43 than there were v Allied ships in the Pacific in the prime of the JNAF in 1942-3, but in order to hope to compare effectivness of defense, you'd have to start by considering air attack effectiveness *relatively* per engagement, rather than the number of attack sorties or sinkings in total. But there's no episode of air attack at all that fully matches the POW/Repulse debacle; and not really any in Med which fully match the smothering with mutiple divebomber hits in the various attacks off Ceylon, either.

But as I said, demonstrating a specific difference in air defense capability based on results in one theater v another, and considering the highly nationalistic prism through which some obviously view these questions...I doubt it.

Just a point on Italian capability. Through basically all of 1940 and into part of 1941, the Italian air threat consisted principally of ineffective medium altitude level bombers. When the Italians introduced torpedo equipped S.79's in late 1940 they had literally 4 a/c in total so equipped, famous for achieving severl hits despite that very small force size. An attack of 40 S.79 sil at once was not until the Pedestal operation in summer of 1942. The Germans didn't use torpedo bombers in the Med during the height of the Anglo-Italian naval war; their torpedo training base was at Grosseto in central Italy from early 42, but priority was given to building capability to use against the Russia convoys. Later on, from Torch landings through summer of '44, German torpedo planes were more active in Med.

Besides limited numbers of S.79 'sil', which were sortie for sortie the most effective Axis antiship a/c in the Med in '40-42, the main threat was from Ju-87's, and Ju-88's acting as divebombers. Ju-88's also acted as level bombers with limited success. German and Italian fighter bombers (Bf109, Re-2001, CR.42) also got a few key hits v British ships but a/c besides S.79 sil, German piloted Ju-87's and *divebombing* Ju-88's the other a/c types were mainly just ramping up the number of sorties. The British formations off Malaya and Ceylon faced more concentrated and purely professional antiship air units than the British faced on average in the Mediterranean, even though they faced cumulatively more attacks and lost more ships in the Med and *some* of those attacks were by highly effective antiship units. 

Joe


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## parsifal (Aug 4, 2010)

Nikademus said:


> Actually shooting down aircraft is a primary mission of both AA and Fighter aircraft. The other facets mentioned are also equally important to both types of weapon systems. The problem with judging AA is that too often, people, including the professionals at the time, tend to fixate on outright kills because its a statistic that can easily and quickly be grasped as a measure of "success". This was a major problem for Germany during the Bombing campaign on their cities. The guys in charge on the ground wern't interested in how many planes were damaged, or driven off, or made to make inaccurate runs..they only wanted to know one thing. "how many of the enemy did you shoot down??!!" This helped fuel arguments on downplaying flak development in favor of more fighters. Ironically in the case of Germany, postwar analysis indicated that flak actually ended up shooting down more enemy planes than the Jagdwaffe....even when not factoring in damaged planes later picked off by fighters.
> 
> The same tunnel vision impacts CAP analysis at times too. The Illustrious Blitz is a good capsule on that. Malta's AA and CAP defenders didn't score much during the "Blitz" and that overshadowed their primary acomplishment, which was disrupting the attacks enough that only a few hits were scored.



I have to disagree. Ships dont put to sea to sail around the ocean to shoot down aircraft, they put to sea to undertake a mission. It is often the case that ships must sail into enemy dominated seas, and risk air attack, but this is still not the primary mission of those ships. 

Fighter aircraft, on the other hand, get airborne for one purpose only, to shoot down enemy aircraft. 

It follows therefore that the AA armament of a ship is there to facilitate the mission of that ship. If the carrying out of that mission enables some losses to enemy aircraft, then so much the better, but the primary purpose remains defensive, that is enabling the ship to complete its mission. if ever there was a demonstrable example of what i am referring to, it has to be the tragedy of PQ-17. Once broken up, the Task Force could not mass sufficient volume of fire, and as a result could not successfully complete the task Groups mission.

I'll put it another way....if a ship does not shoot down a single aircraft, but is abale to undertake its mission without loss or damage, that ship, and its AA can be considered a success. If it shoots down aircraft b\ut is prevented from undertaking its stated mission, by sinking, or damage, or scrapping of the mission, the ship, and its AA have failed in their primary mission. If the ship manages to shoot down aircraft, and complete its mission, its a success with a bonus "score", so to speak. 

If this accepted, then the RN demonstrates in spades that its AA was adequate. Someone mentioned that the RN lost 30 cruisers in the war whilst the USN only lost ten. Well, this is true, but is a gross misuse of basic statistics. In fact in the time frame that the USN was being shot at, the RN lost only 18 cruisers, and of this only 5 were lost to enemy air attack. in that period the USN lost one cruiser to air attack. However the RN often operated in conditions of enemy control of the airspace, wheras the USN after the end of 1942, usually operated under conditions where the naval units were concentrated, and the the airspace was either under their control, or, at minimum, was under challenge by their own airpower. It is simply invalid to start comparing the losses of one theatre to those in another. The USN enjoyed advantages that the RN was not privy to until very late in the war. In the circumstances where the operating conditions were similar, such as off the coast of japan in 1945, the RN does not appear to have been any worse off with its AA arrangements than the USN. Both took losses to the Kamikaze attacks, and both had significant successes as well.


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## Shortround6 (Aug 4, 2010)

Comparing the AA ability of either navy in 1945 to the each others ability or even their own ability at earlier periods of the war ignores the large advancements in number of AA guns mounted, types of AA guns mounted, types of mountings used (powered vs unpowered) , fire control and ammunition (VT fuses) . 

While I mentioned earlier the RN destroyers armed with a pair of quad .5" MGs and was rebutted by American destroyers with 4-8 .50 cal guns. 
this rather ignores the facts that the British main armament of 4.7in guns was rather useless for anti-aircraft work. Older destroyers having a max elevation of 30 degrees and somewhat newer having 40 degrees as a book figure but only obtainable by pulling up sections of the deck grating to allow for gun recoil. A full 40 "degrees was finally achieved but this compares badly to the 85 degrees of the US 5"/38.
Few if any British 4.7 were power operated until the twin mount on the Tribal class. I believe ALL destroyer mounted 5" 38s were power operated. 
The British 4.7 had a rate of fire of 10-12 rpm. Most if not all destroyer 5"/38s had a rate of fire of 15-22rpm for a 20% margin of superiority for the US destroyers at worst and double the rate of fire at best. 
While the RN was at the forefront in some developments in AA it's very size conspired against it as did the war situation. It is one thing to develop or introduce a new gun or mounting or fire control device, it is quite another to retrofit to a number of ships the size of the RN, especially if the ships are spread around the world and are being worked so hard that they cannot be docked for routine maintenance let alone refits. Combine that with a shortage of manufacturing capacity and AA refits were slow in coming for many ships. Or refits were parceled out in dribs and drabs. A couple of 20mm guns now, a couple of 20mm guns months from now. 
The landing of a set of torpedo tubes for either a single 4" or 3" unpowered, local control AA gun was more of a morale booster than an effective AA defense. it also shows that no other AA guns were available.


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## Nikademus (Aug 4, 2010)

parsifal said:


> I have to disagree. Ships dont put to sea to sail around the ocean to shoot down aircraft, they put to sea to undertake a mission. It is often the case that ships must sail into enemy dominated seas, and risk air attack, but this is still not the primary mission of those ships.
> 
> Fighter aircraft, on the other hand, get airborne for one purpose only, to shoot down enemy aircraft.



The same can be said of Fighters. They are there to fullfill a mission which is generally broken down into two or three types; 1) Fleet defense 2) Strike escort 3) sweep. A primary means of acomplishing this is to "shoot down enemy planes" but said missions can be acomplished through indirect means as well, particularily in the case of 2). Same for Anti-Aircraft. The primary mission of AA is to defend said ship/TF. The most direct means to acomplish this is to hit and shoot down enemy planes but in lieu of that, driving off enemy planes is acceptible to ensure survival of the ship and to maintain systems integrity. A problem with the argument that AA is primary an attempt to "ward off" enemy attackers exclusively is that better trained crews are not going to be warded off in general. Highly trained crews with good morale tend to press home their attacks. Similar situation existed in the case of Kamakaze's. Behind such fanaticism, the USN was faced with the challenge of hitting as quickly and hard as it could as even a damaged plane might still hit a ship. Advances in AA technology (including the vital VT fuse) were all about HITTING the enemy planes, not driving them off. IMO, saying AA is primary a means to ward off enemy planes is like saying Anti-ship weapons arn't really there to "hit" an enemy ship but more as a deterrent to sticking around the battlefield. You might indeed drive off the ship, but in the process you are trying your damnest to HIT the enemy ship.


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## RCAFson (Aug 4, 2010)

Shortround6 said:


> Comparing the AA ability of either navy in 1945 to the each others ability or even their own ability at earlier periods of the war ignores the large advancements in number of AA guns mounted, types of AA guns mounted, types of mountings used (powered vs unpowered) , fire control and ammunition (VT fuses) .
> 
> While I mentioned earlier the RN destroyers armed with a pair of quad .5" MGs and was rebutted by American destroyers with 4-8 .50 cal guns.
> this rather ignores the facts that the British main armament of 4.7in guns was rather useless for anti-aircraft work. Older destroyers having a max elevation of 30 degrees and somewhat newer having 40 degrees as a book figure but only obtainable by pulling up sections of the deck grating to allow for gun recoil. A full 40 "degrees was finally achieved but this compares badly to the 85 degrees of the US 5"/38.
> ...




according to:
USA 5"/38 (12.7 cm) Mark 12 
The older models of the 5in/38, on prewar destroyers, and other ships had a rate of fire, of about 12 -15 RPM, and it was only the newer ships with improved fuze setters that could fire faster. According to 
Goldplaters, 1500-ton destroyers and 1850-ton destroyer leaders
All USN destroyers prior to 1939 had a close range armament of 4 x .5" MG. 
So the RN destroyer close range armament of either 2 x 40mm pom-pom, 2 x quad .5" or 1 x quad 40mm pom-pom and 2 x quad .5" is still superior.

All the Tribal class and the J-K class had 8 or 6 power worked DP twin 4.7" guns with an main armament AA FC system. No German or Italian destroyers had a DP main armament. The IJN destroyers had very little in the way of DP capability and their 5in main armament is described as:
"_However, the very slow training speeds and lack of power ramming made these mountings almost useless against the fast-moving aircraft of World War I_I""
Japan 12.7 cm/50 (5") 3rd Year Type

The more modern RN destroyers were limited to 40 deg elevation but this still allowed for engaging most aircraft throughout some of their attack, and obviously could engage torpedo bombers continuously. According to this source:

"_In theory, the 5in gun could counter either horizontal or torpedo bombers; it could not fire nearly fast enough to present any threat to dive bombers,which, ironically, were probably the most lethal threat to fast maneuverable craft such as destroyers._" US Destroyers-An Illustrated Design History, Friedman, p203
So it seems that against DBs, a destroyer's best defence was its close range weapons, and here the RN did not seem to be "substandard", so even if their early war/prewar armament was not sufficient, it was still as good or better then everyone else's. The RN also, pre and early war, re-armed older ships as dedicated AA cruisers, and introduced AA sloops with a heavy armament of 4" guns, with 80 deg elevation. The RN began building large numbers of Hunt class destroyers, early in the war, and they all had either 4 x 4 or 6 DP 4in guns, a quad pom-pom and several smaller weapons. 

So compared to the USN, it is hard to say if the RN was really behind, but certainly compared to the Axis ships, the RN destroyers are ahead in terms of AA armament and fire control. The RN was certainly ahead of everybody in terms of AA radar fire control.


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## JoeB (Aug 4, 2010)

Besides any doctrinal debate about the role of AA and fighters in repelling air attacks, as a practical matter when both fighters and AA were defending a group of ships, it's usually very hard to disintangle which shot down how many enemy a/c. The total claims almost always exceed the enemy losses, and specific enemy accounts will sometimes allow AA or fighters to be credited pretty certainly, but usually won't.

Same or more so when it comes to evaluating light v heavy AA.

Debates about RN AA fire control on other boards have run up on the rocks over this issue. The boosters of RN heavy AA as underrated present figures for AA claims in Med as if true and as if all from heavy AA. Then the next fall back position is that overall Axis losses weren't so much less than AA claims, but fighters shot down an intdeterminate high % of the a/c and light AA probably did too. And, a high % of Axis bomber losses in attacks on RN in Med (and Malta) were ditching/crashlanding on way back, which were certainly successes of the defense, but very rarely can those cases be nailed down to a single cause with available info. Same is true in Pacific, but I'm not aware of people trying to claim absolute true losses of Japanese a/c v USN defenses, rather than eg comparative effectiveness of USN VT v USN time fuzed 5" fire, or something like that, where it's reasonable to compare relative claims as at least a rough idea.

Only in cases where a/c attacked ships without air cover is it usually possible to evaluate AA claim/loss, and back to the doctrinal type consideration, one could argue that AA's role is to distract and hamper air attacks, or mop up the remnants, as an add to effective fighter cover, and it isn't that relevant how the AA would do on its own against a large scale attack by competent antiship air units unmolested by friendly fighters; that's something that simply had to be avoided.

Joe


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## RCAFson (Aug 4, 2010)

JoeB said:


> But the Brit uber-alles type posters on the internet with 'far bigger air threat in Med' are really being quite ridiculous, as shown by the RN's own operations early in the Pacific War. There were a larger number of *engagements* between Axis a/c and Allied ships in Med througth whole of 1940-43 than there were v Allied ships in the Pacific in the prime of the JNAF in 1942-3, but in order to hope to compare effectivness of defense, you'd have to start by considering air attack effectiveness *relatively* per engagement, rather than the number of attack sorties or sinkings in total. But there's no episode of air attack at all that fully matches the POW/Repulse debacle; and not really any in Med which fully match the smothering with mutiple divebomber hits in the various attacks off Ceylon, either.
> 
> But as I said, demonstrating a specific difference in air defense capability based on results in one theater v another, and considering the highly nationalistic prism through which some obviously view these questions...I doubt it.
> 
> ...



It is a question of telling the real story, and it is historically inaccurate to suggest that the Luftwaffe crews were cowards, unwilling to press home their attacks. If they didn't press home their attacks on RN ships, then it suggests that they had powerful reasons to fear for their safety. Which is it?

The Luftwaffe did attack RN ships with great determination, (and it is an real insult to the Luftwaffe and the RN/RCN/RNZN/RAN to suggest otherwise) and flew hundreds of attack sorties, off Norway, Dunkirk, Malta and Crete, so that by June 1941, the RN must have faced a far higher numbers of attacks than the USN, did in 1942-43. Many RN ships were sunk, but they also shot down large numbers of attacking aircraft, mainly with their pre-war outfit of AA weapons, although some 20mm guns were in service by June 1941. 

The IJN was able to overwhelm isolated numbers of elderly RN ships in the Indian Ocean and so conducted DB attacks under virtually peacetime practise conditions, where the Luftwaffe DBs often to had to brave the fire of a massed fleet, to press home their attacks. The Luftwaffe often carried 500kg bombs, which were rarely used by the IJN, while Luftwaffe aircraft were, typically, heavily armoured and had self sealing fuel tanks, while the Japanese planes had no crew or fuel protection at all. 

As for POW/Repulse, give me an example of a similar encounter by another navy, where large numbers of TBs where able to attack with no worries about CAP and/or a screen of modern cruisers and destroyers. 

While you attempt to minimize the IAF TB attacks, you also state that they achieved some successes, so I guess "some" of the IAF crews were "determined". The TB attack against Operation Halberd, was certainly determined, and it also got a very hot reception by RN AA.
Operation Halberd - Wikipedia, the free encyclopedia


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## Shortround6 (Aug 4, 2010)

RCAFson said:


> according to:
> USA 5"/38 (12.7 cm) Mark 12
> The older models of the 5in/38, on prewar destroyers, and other ships had a rate of fire, of about 12 -15 RPM, and it was only the newer ships with improved fuze setters that could fire faster. According to
> Goldplaters, 1500-ton destroyers and 1850-ton destroyer leaders
> ...


 The rate of fire also had a lot to do with the ammo hoists so a fair number of the pre-war destroyers (the ones with the base ring mount) could do all right.
The older single 40mm pom-poms are a problem. The British considered them so good they replaced then with the Quad .5in mount which was no great item itself. While these may be considered better close range armament than the American four .50cal guns when you consider that for the British A through I class they were the ONLY effective AA guns on the destroyer, few of these early class (if any) had an AA director an only the H and I class could realistically elevate their 4.7in guns above 30 degrees, things don't look so good. 
As a comment on how well the 4.7in guns of the early classes worked as AA guns it may be noted that many of them landed half their torpedo armament in order to mount a single WW I era 12pdr (3in) AA gun in local control which aside from raising the morale of the sailors was just about useless. 
Granted the 4 barreled pom-pom gun was great improvement but it was only on the Tribal class and the J class and what few K class that were in service when the war broke out. 


RCAFson said:


> All the Tribal class and the J-K class had 8 or 6 power worked DP twin 4.7" guns with an main armament AA FC system. No German or Italian destroyers had a DP main armament. The IJN destroyers had very little in the way of DP capability and their 5in main armament is described as:



I guess it depends on what you call dual purpose. The British thought so much of the dual purpose capability of the J-K class with their power worked twin 4.7in guns that they also landed half the torpedo armament to mount a single 4in gun in local control to beef up the AA capability. It actually wasn't much more use than the 12pdr. Some Tribal Class destroyers landed X mount of the 4.7in guns to mount a twin 4in mount. The fire control director was modified to accommodate the dual ballistics. I think that says something about what was thought of the twin 4.7in as an AA gun. 



RCAFson said:


> "_In theory, the 5in gun could counter either horizontal or torpedo bombers; it could not fire nearly fast enough to present any threat to dive bombers,which, ironically, were probably the most lethal threat to fast maneuverable craft such as destroyers._" US Destroyers-An Illustrated Design History, Friedman, p203



True enough but that page goes on to point out that it was thought that the dive bombers would go after higher value ships and leave the DDs alone (wishful thinking?) and that devoting armament space/weight to heavier machine cannon (the 1.1in mounted on the 1850 ton leaders) would mean a sacrifice in the 5in armament which was planned as as part of the fleet AA defense. The destroyers forming an AA screen around the higher value ships. The US may have gotten the mix of weapons wrong but they were thinking about a STRONG AA gun defense of the fleet to include ALL ships. 



RCAFson said:


> So it seems that against DBs, a destroyer's best defence was its close range weapons, and here the RN did not seem to be "substandard", so even if their early war/prewar armament was not sufficient, it was still as good or better then everyone else's.


Granted the German and French 37mm guns wer a bit of a joke but the German 20mm guns had to be worth something even if they are the early slow firing models.


RCAFson said:


> The RN also, pre and early war, re-armed older ships as dedicated AA cruisers, and introduced AA sloops with a heavy armament of 4" guns, with 80 deg elevation. The RN began building large numbers of Hunt class destroyers, early in the war, and they all had either 4 x 4 or 6 DP 4in guns, a quad pom-pom and several smaller weapons.


 True but a few special AA ships per task force is not quite the same thing. And considering that from the Benham class on 2 US destroyers could come close to putting up as much heavy AA fire as one converted British AA cruiser


RCAFson said:


> So compared to the USN, it is hard to say if the RN was really behind, but certainly compared to the Axis ships, the RN destroyers are ahead in terms of AA armament and fire control. The RN was certainly ahead of everybody in terms of AA radar fire control.



There are two problems with fire control and radar, one is development and the other is deployment. While the RN may have been a leader in development it tended to fall down in deploying systems that worked well at the beginning of the war and because of the war situation and the size of the British fleet retrofits came slow and hard causing many older ships to fight on without the modern equipment. Things did get better for the British while for the axis navies things usually got worse, their improvements came even later and in even smaller numbers. US also had 2 years to learn from the British what worked and what didn't before more than a few of their ships got into a shooting war.


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## RCAFson (Aug 4, 2010)

As of Sept 30 1939 (by my count using data from the web)the USN had:

8 farragut
18 mahan
4 Gridley class
8 bagley
5 benham
43 destroyers with DP 5" guns in commission, although some of these might not have been fully completed. 

The RN had 
16 Tribals
10-JK class
6 sloops (including 3 Egret class with 4 x 4" twin mounts)
4 AA cruisers
36 light ships with DP armament.

So the USN had a slight lead. We can debate the efficacy of DP guns against DBs, but it is doubtful that they were very effective, and the RN probably should have installed automatic weapons rather than 3"/4" HA guns, in place of the torpedo tubes. Of course the RN learned these lessons the hard way but did pass on all the info gained to the USN. Again no German or Italian destroyer ever had any DP main guns. 



> There are two problems with fire control and radar, one is development and the other is deployment. While the RN may have been a leader in development it tended to fall down in deploying systems that worked well at the beginning of the war and because of the war situation and the size of the British fleet retrofits came slow and hard causing many older ships to fight on without the modern equipment. Things did get better for the British while for the axis navies things usually got worse, their improvements came even later and in even smaller numbers. US also had 2 years to learn from the British what worked and what didn't before more than a few of their ships got into a shooting war.



I have already detailed how the RN had 56 ships (and many others with type 279/280/281) outfitted with Type 285 radar by Sept 28 1941, when no other navy had a single operational AA FC radar in service.

While only the Tribal and JKclass had quad pom-poms in Sept 1939, all RN capital ships and many modern cruisers had quad or octuple pom-poms as well, at a time when the USN depended almost universally on the .5" single MG, on almost all its ships.



> True enough but that page goes on to point out that it was thought that the dive bombers would go after higher value ships and leave the DDs alone (wishful thinking?) and that devoting armament space/weight to heavier machine cannon (the 1.1in mounted on the 1850 ton leaders) would mean a sacrifice in the 5in armament which was planned as as part of the fleet AA defense. The destroyers forming an AA screen around the higher value ships. The US may have gotten the mix of weapons wrong but they were thinking about a STRONG AA gun defense of the fleet to include ALL ships.



And this was the thinking current in the RN as well, which led to the decision to retain a 40 deg elevation on the twin 4.7in gun, as this elevation was sufficient to provide 4.7in AA fire to protect ships being escorted by destroyers.
4.7 inch QF Mark XII - Wikipedia, the free encyclopedia


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## Juha (Aug 5, 2010)

RCAFson
the 4.7” guns of Tribals, Js and Ks had max 40deg elevation, the US DDs in your list had 5”/38s with max 85deg elevation, a bit difference, especially when fighting against dive-bombers. That’s why Js and Ks sacrificed ½ of their TTs to get even one real H/A gun aboard. In Tribals, which had only one quadruple TT anyway, Y-turret was changed to a 4” twin mount. So I would say that USN had significant lead in DP armed DDs. AA protection by guns with only 40deg elevation was a dubious asset, even high flying level bombers would have been out of reach when it really mattered ie when they approached their bomb-release point.

On automatic AA British had a lead, IIRC only US leaders had 2 quad 1.1” AAA mounts and their twin 5” mounts were LA type.

Juha


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## RCAFson (Aug 5, 2010)

Juha said:


> RCAFson
> the 4.7” guns of Tribals, Js and Ks had max 40deg elevation, the US DDs in your list had 5”/38s with max 85deg elevation, a bit difference, especially when fighting against dive-bombers. That’s why Js and Ks sacrificed ½ of their TTs to get even one real H/A gun aboard. In Tribals, which had only one quadruple TT anyway, Y-turret was changed to a 4” twin mount. So I would say that USN had significant lead in DP armed DDs. AA protection by guns with only 40deg elevation was a dubious asset, even high flying level bombers would have been out of reach when it really mattered ie when they approached their bomb-release point.
> 
> On automatic AA British had a lead, IIRC only US leaders had 2 quad 1.1” AAA mounts and their twin 5” mounts were LA type.
> ...



DBs are not the only type of attack, but even then the 40 deg guns could still engage Dbs attacking other ships, and as Friedman states, 5" calibre guns are little threat to DBs anyway. Yes, I agree that until VT ammo was available automatic weapons were the preferred way to deal with DBs and the RN should have added more of these in preference to a not very effective HA 4" gun.

OTOH, 30 of the RN ships (16 Tribals, 10 JK class and 4 AA cruisers) had a quad pom-pom, versus only .5" mgs on the USN ships. From other reading it seems that the quad 1.1" which was to have armed the USN destroyer leaders (which had no 5" AA FC) was delivered very late and was not ready by Sept 1939.


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## parsifal (Aug 5, 2010)

The debate occurring at this point seems to revolve around whether the fighting in Europe was as determined and as proficient as those that occurred in the Pacific. An ancilliary question is whther the RN faced a relatively tougher or easier or about the same level of difficulty in the fighting in the med 1941-2 as the USN did a year later. The nearest analogy I guess would be to compre the fighting around Malta and Crete to that which occurred in the Solomons from March through to say November 1942.

I cannot answer whether the Germans and Italians were any more or less proficient than the Japanese in their aeronaval attacks. According to Bragadin, in that period the Italians were responsible for 40% of the tonnage losses to the RN and the merchant service as a result of their torpedo squadrons. People tend to denigrate their efforts because there were no big ships sunk by air attack, but as I recall after December 1941, they were responsible for the sinking of one of the five British cruisers by air attack, the Germans responsible for two, and the the Japanese for two. They sank more merchant tonnage in the med than the Germans. Our view of them is often coloured by their lacklustre belif and use of high level bombing. Once the uselessness of this was relaized, and steps taken to rectify the problem by using aerial torpedo attacks, which began in earnest from January 1941, they remained a potent force

The abilities of the germans in aeronaval capability started the war in a fairly lacklustre fashion, but they too developed specialist ant-shipping units that proved quite devastating. They were slow on the uptake in terms of torpedo bombing, but they more than madde up for this with their divebombing capabilities.

The Japanese had an undoubted prowess in anti-shipping capabilities, but as training levels slumped, there was a marked drop in their skill levels. The Vals scored a hit ratio above 80% in the Indian Ocean, as Joe (and myself) have pointed out. However by 1944, it is estimated that this accuracy had slumped to less than 10%. I would expect a similar drop in proficiency for the other major weapon systems like torpedo squadrons. They countered this slump in training by introducing massed kamikaze attacks, which resulted in a marked increase in USN ship losses.

It is very difficult and not entirely valid to try to compare the ferocity and effectiveness of fighting in one theatre to that which existed in another. If you want to compare the scale and ferocity of the fighting in the mediterranean with that in the pacific, then in my opinion you have to at least compare battles in similar time frames, then make some estimation of the relative merits of the crews and equipment involved, and finally try to determine the tnumbers and effectiveness of those systems. 

Most of these variables are simply unknown, or so objective as to be beyond quantification. But in one area i have no doubts. Comparing the numbers of enemy aircraft involved, there is no question that the RN faced a far greater number of enemy aircraft thgan their American counterparts, at least in the beginning. The attacks against the "Excess" group of convoys were resisted by 226 Luftwaffe aircraft, and about 100 RA aircraft (but only about 30 of these can be considered effecetive). I believe the RN forces operating off Crete were faced by about 700 German aircraft not including the transports. These were just the aeronaval units of the two FliegerKorps. During the Pedestal convoys, the RN faced more than 700 axis aircraft, though the axis faced the perrennial problem of being unable to concentrate their forces

The Japanese part of the equation is complicated by the intervention by her carrier based air units. These were usually countered by the presence of American based carrier planes, but it was during these short, sharp engagement that the majority of the damage was done to the USN. At other times the numbers of aircraft involved was far less than those 
being employed by the Axis in the Med, so from that single standpoint, there is absolutely no doubt that the scale of fighting was much more intense in the med than in the SW pacific. Later things did change....there were more Japanese forces committed, and the intensity of the battles increased accordingly, but I think this is not a valid comparison.


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## Nikademus (Aug 5, 2010)

parsifal said:


> The debate occurring at this point seems to revolve around whether the fighting in Europe was as determined and as proficient as those that occurred in the Pacific. An ancilliary question is whther the RN faced a relatively tougher or easier or about the same level of difficulty in the fighting in the med 1941-2 as the USN did a year later.



The Med fighting saw more surface battles than any other Theater and while there were no carrier vs carrier air battles, the proximity of large land based air assets more than made up for this. The need to continually provide convoys on both sides kept the air forces and navies busy. The intensity at times matched anything seen in the Pacific with the exception of large carrier airstrikes. A major difference was in the Pacific clashes tended to be more sporadic but violent while in the Med it might be seen (very roughly) as a more of an even tempo over a longer period of time. 

Some fun with numbers: (Source: O'Hara)

Surface Engagements by Ocean/Sea

Atlantic: 49
Artic: 8
Baltic Black Seas: 5
Indian Ocean: 14
*Pacific*: 36
*Med*: 55

enemy warship tonnage sunk by Nation:

Italy: 145,800
Germany: 169,700
UK: 161,200
US: 33,900

(Luftwaffe accounted for 30% of Allied warship losses compared to 9% Regia Aeronautica)

Italian aerial torpedo squadrons were late in being started and was stunted by limited availability of torpedoes, crews initially had little training but proficiancy rose up slowly. High attrition though eventually led to loss of proficiancy but one that was matched by an increase in numbers available. As mentioned, while they scored little against warships, they were a major threat to merchants in convoy along with "special weapons" (MTB's etc). 

German airpower proved more effective than Italian airpower in terms of Allied warship losses.

All in all, the Med was no picnic.


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## parsifal (Aug 5, 2010)

Nikademus said:


> The Med fighting saw more surface battles than any other Theater and while there were no carrier vs carrier air battles, the proximity of large land based air assets more than made up for this. The need to continually provide convoys on both sides kept the air forces and navies busy. The intensity at times matched anything seen in the Pacific with the exception of large carrier airstrikes. A major difference was in the Pacific clashes tended to be more sporadic but violent while in the Med it might be seen (very roughly) as a more of an even tempo over a longer period of time.
> 
> Some fun with numbers: (Source: O'Hara)
> 
> ...


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## Nikademus (Aug 5, 2010)

parsifal said:


> I would have to disagree that either the Med or the Pacific were not driven by carrier operations, or at least aeronaval operations.



Not sure if this is in response to me, so i'll clarify. The surface battle comparison number was posted to emphasis the point (made very well by O'Hara's recent tomb on the subject of the Med), that the Med was a serious Theater of operation yet it tends to either go under the radar (at least in the U.S.....Europe is a different matter), or is heavily discounted because, as you alluded too, the quality of the opposition (i.e., the Italians) are disparaged. Back in warships1.com days in the 1990's, when one would occasionally compare USN performance to UK performance, say at night.....an inevitable response would be "Oh but look who they were fighting!" Ironically, as shown....more surface battles were fought there than anywhere else. These battles may not have been the size of a Leyte Gulf......but it wasn't beer and pretzels either.

I agree that carriers played a key role in the Med for the UK. Without them first and formost.....Malta could not have been kept running and from a military standpoint their presence was a constant source of concern for the RM. In a way, it dovetails nicely with the position of Bergerud in his study of South Pacific air operations. In it he de-emphasised the importance of carrier vs carrier clashes vs. that of land air battles which were much more steady and prevalent (compared to the two clashes CV vs CV of which the overall result was largely a draw in the big picture) In the Med....carriers were a vital component to countering the large proximity of land based air forces and also provided the means by which the UK land based air forces could be continually replenished and kept up to strength so that the RAF could stay in the battle both offensively and defensively.


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## BombTaxi (Aug 5, 2010)

Comparing the Med and the Pacific is apples and oranges anyway. The RN were fighting an essentially defensive campaign, keeping the seaways open to resupply Malta and NA and maintain the integrity of the Suez Canal. Offensive ops were mainly dedicated to supporting these essentially defensive aims, or later to interdicting Axis attempts to resupply thier own forces in NA.

By contrast, the USN was primarily engaged from day one in a pre-planned campaign designed to get them from California to the Japanese Home Islands. Their only defensive actions were early on, at Coral Sea and Midway. Very different warfighting philosophies were in play too. The USN saw carriers as the primary striking arm of the fleet, whereas the RN still saw carriers primarily as scouting tools and, in the Med, as large aircraft transports. The difference is shown in early-war CV and air group design; USN carriers were designed to rapidly transport large, strike-orientated air groups to the point of engagement as rapidly as possible, whereas RN carriers emphasised greater protection of smaller vessels, carrying small air groups in which almost every aircraft (e.g Skua, Albacore, Swordfish, Fulmar and Firefly) had a secondary reconnaissance capability.


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## parsifal (Aug 5, 2010)

Hi Nikademus

Yes my comments were in reply to your post 117. We are pretty much aligned in our positions. If we feed that back into this question of AA effectiveness, if one consideres the numbers of aircraft facing the RN, and then the generally poor levels of air cover (compared to that enjoyed in the Pacific) the reasons for the high loss rates in British warships start to make sense. Moreover, the comments about the relative lack of effectiveness of British seaborne flak need to be taken with a bit of salt. There is no doubt that British AA was weak, but in the time frame we are talking about (1940-42) there is not as much difference I think as is being attempted to be argued here. In the Excess convoys, I believe the British task force (there were actually four task forces, but only one engaged FKX), managed to shoot down 13 aircraft (based on Luftwaffe reports). Subsequently the AA defences managed to keep the Germans at bay for 10 days (????) without further serious damage to the carrier. Whether you want to measure flak effectiveness by numbers of aircraft shot down, or in terms of protecting the ship, the efforts by the RN in that operation are not too bad. 

By comparison, where flk defence was not maintained, such as over PQ-17, the loss rates for unprotected ships go through the roof. If the problem is looked at from the point of view of operational results, I just dont get the argument that RN AA sucked at what it was supposed to be doing.


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## BombTaxi (Aug 5, 2010)

As one of the people criticising RN AAA defences, I should clarify by acknowledging that it did a job. However, in the early days it was not doing the job as well as it could have done. The installation of low angle mounts for DD main batteries was, IMHO, a mistake, one which the USN avoided in their destroyer designs. The USN clearly had a keen appreciation of the threat posed by aircraft - hardly surprising give Mitchell's experiments off Cape Hatteras. The RN, on the other hand, was still planning to fight another Jutland, evidenced by it's optimisation of armaments for surface engagement and the attitude to CVs I noted above. Had the RN followed the USN philosophy and provided more medium-calibre automatic weapons from day one, coupled with HA mounts for 4 and 4.7in guns, it might have suffered fewer losses to enemy air power in the earlier stages of the war.


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## Nikademus (Aug 5, 2010)

parsifal said:


> Hi Nikademus
> 
> Yes my comments were in reply to your post 117. We are pretty much aligned in our positions. If we feed that back into this question of AA effectiveness, if one consideres the numbers of aircraft facing the RN, and then the generally poor levels of air cover (compared to that enjoyed in the Pacific) the reasons for the high loss rates in British warships start to make sense. .




Yup. I also note alot of attention to detail in the technical specifics of the heavy AA guns. There's no dispute that the 5/38 was a technically superior mount to the 5.25in but early-midwar wartime results were not all that disparate in the end. Even at Santa Cruz the pre-VT heavies accounted for approx only 5% of the losses. USN AA performance at the first three carrier skirmishes were not markedly superior to RN AA returns. Santa Cruz saw the first marked increase in outright AA losses and was mainly driven by the addition in substantial numbers of 20mm and 40mm Bofors.


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## red admiral (Aug 5, 2010)

> Had the RN followed the USN philosophy and provided more medium-calibre automatic weapons from day one, coupled with HA mounts for 4 and 4.7in guns, it might have suffered fewer losses to enemy air power in the earlier stages of the war.



It's overly harsh to compare early-war RN ships with late-war USN ones.

The choice of not having dual purpose guns on the destroyers was a fairly simple one of cost. Dual purpose guns cost more and need bigger ships which again cost more. The difference is not insignificant. The actual effectiveness of dual purpose guns before proximity fuzes was pretty much negligible. They served as little more than a distraction. 40deg elevation still gave the capability for barrage fire over mutually supporting ships, which is how they were used. The dual purpose guns in the USN were used in the same way - barrage fire, because the fire control problems at close range was too demanding.

The RN was far ahead in deployment of an effective medium calibre automatic weapon with the 2pdr. At the same time US ships were being armed with small numbers of machine guns and later 1.1" guns. It would have been nice to have more 2pdr guns, but there were production difficulties in producing enough, and then later on with the more effective 40mm Bofors.

Was RN anti-aircraft fire in the early war years poor? Yes it was, but so was everyone else's. The large deployment of the 2pdr actually made it better off than most navies. Later in the war - difficulties in producing enough 2pdrs, 40mm Bofors, and the simply time to refit ships lead to her position declining.


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## RCAFson (Aug 5, 2010)

BombTaxi said:


> As one of the people criticising RN AAA defences, I should clarify by acknowledging that it did a job. However, in the early days it was not doing the job as well as it could have done. The installation of low angle mounts for DD main batteries was, IMHO, a mistake, one which the USN avoided in their destroyer designs. The USN clearly had a keen appreciation of the threat posed by aircraft - hardly surprising give Mitchell's experiments off Cape Hatteras. The RN, on the other hand, was still planning to fight another Jutland, evidenced by it's optimisation of armaments for surface engagement and the attitude to CVs I noted above. Had the RN followed the USN philosophy and provided more medium-calibre automatic weapons from day one, coupled with HA mounts for 4 and 4.7in guns, it might have suffered fewer losses to enemy air power in the earlier stages of the war.



The RN actually put a lot more focus on 40mm and smaller automatic weapons, than the USN, or any other navy, prior to Sept 1939, and these turned out to be the most effective AA weapons throughout WW2. Focusing exclusively on medium calibre guns is a bit of a red herring, when they were not particularly efficient at knocking down aircraft. A Tribal or JK class destroyer with a quad pom-pom and 2 quad .5in MG probably has a greater chance of destroying a DB than another destroyer with 85 deg main armament, but only 4 x .5" MG.


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## Juha (Aug 5, 2010)

Hello RCAFson
IMHO RN didn’t have any decent DP gun armed DDs early in the war save those couple Ls armed with 4 4” twin mounts instead of with the class normal 3 4.7” twin mounts and half of the Os and Ps which had 4 single 4” guns instead of 4 single 4.7” guns. Later from S Class onwards they got DDs with 55deg max elevation main armament, first with 4.7” guns and then with newer 4.5” guns. And even 55deg elevation wasn’t same than 85 deg.

On AAA, quad 2pdr wasn’t excellent gun, IIRC RN itself later thought that a twin Bofors was a better weapon and those quad .5 Vickers guns were rather useless. And that quad 2pdr in Tribals was badly wooded before they removed the rear/mizzen mast.

Juha


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## BombTaxi (Aug 5, 2010)

Also, as we have also discussed, direction systems for RN vessels early in the war were substandard, and it took time for them to be replaced. To respond to redadmiral, I'm actually comparing pre-war to pre-war: the USN was fitting HA mounts to the Benson-Gleaves class, which were in widespread service by Pearl Harbour, but first entered service in 1938. 

I'm not debating the fact that early war, DP guns were mostly useful for barrage fire; certainly the results from pre-war HACS testing left the RN with little choice. But surely you see that a mount with 85 degree elevation can cover a greater volume of sky than onw with 40 degrees? And that means more chances to break up the enemies attack, increasing your chances of survival...


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## RCAFson (Aug 5, 2010)

Juha said:


> Hello RCAFson
> IMHO RN didn’t have any decent DP gun armed DDs early in the war save those couple Ls armed with 4 4” twin mounts instead of with the class normal 3 4.7” twin mounts and half of the Os and Ps which had 4 single 4” guns instead of 4 single 4.7” guns. Later from S Class onwards they got DDs with 55deg max elevation main armament, first with 4.7” guns and then with newer 4.5” guns. And even 55deg elevation wasn’t same than 85 deg.
> 
> On AAA, quad 2pdr wasn’t excellent gun, IIRC RN itself later thought that a twin Bofors was a better weapon and those quad .5 Vickers guns were rather useless. And that quad 2pdr in Tribals was badly wooded before they removed the rear/mizzen mast.
> ...



The RN also had about 25 Hunt class destroyers in commission by the end of 1940, and they alll had 2 or 3 twin 4" HA mounts, a quad pom-pom and 2 quad .5" or 2 x 20mm. Another 20 entered service by the end of 1941. A number of WW1 destroyers were also refitted with twin 4" HA guns. to provide coastal escort.

The Bofors was a better gun overall than the Pom-pom, but only the Dutch navy had them in service in 1939, followed by the RN in 1941, albeit in limited numbers. The USN didn't get them in quantity until late 1942. If a quad .5" is useless, then what does that say about single .5" guns? However, I for one, would not want to fly close to a ship that is firing at me with 4 .5" MGs, at a combined rate of 50 rounds per second. The quad pom-pom also had something like a 100 round magazine capacity and could fire for about a minute without reloading, where the bofors must be constantly fed ammo.

Again, we are focusing on RN versus USN, when clearly the RN was far ahead of the Axis navies in AA.


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## RCAFson (Aug 5, 2010)

BombTaxi said:


> Also, as we have also discussed, direction systems for RN vessels early in the war were substandard, and it took time for them to be replaced. To respond to redadmiral, I'm actually comparing pre-war to pre-war: the USN was fitting HA mounts to the Benson-Gleaves class, which were in widespread service by Pearl Harbour, but first entered service in 1938.
> 
> I'm not debating the fact that early war, DP guns were mostly useful for barrage fire; certainly the results from pre-war HACS testing left the RN with little choice. But surely you see that a mount with 85 degree elevation can cover a greater volume of sky than onw with 40 degrees? And that means more chances to break up the enemies attack, increasing your chances of survival...



The prewar USN Mk33 FC system was not very good, by all accounts, and the Mk37 which was better. really didn't enter service till 1941. The Tribal class had an AA FC system, and they began to enter service in 1938.

In fact prewar HACS testing was quite encouraging, and maybe gave the RN false confidence, after all they did shoot down 6 target drones in one month, in 1936. As for sky coverage it all depends, because if you have, say 10 destroyers around a carrier, for example, and an attack come in against the carrier, most of the destroyers ( except for the ones directly overflown) will be able to continuously engage the targets until they attack, as a destroyer screen was typically 5-6000 yards away from the centre ship. As mentioned previously. LA guns are lighter, so a destroyer can carry more of them, and after 1938 all RN destroyers had a quad pom-pom for close range defence. 

Again. no German or Italian destroyers had any DP guns.


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## Juha (Aug 5, 2010)

Hello RCAFson
Yes Hunt had long-range AA capacity, but not even RN counted them as Fleet destroyers, they were too slow for fleet work and the early marks lacked torpedoes. But you are right and I should have use definition Fleet destroyers. And I made another mistake, there were four 4” Ls and Ls and Ms 4.7” mountings had max 50deg elevation, even if they were not well suited for AA work.

on .5”, US .5 was much better weapon than RN .5 Vickers, not saing that US .5 was adequate for AA work in 40s but it was clearly better than its British cousin.

Pom-pom was rather prone to stoppages, IIRC mainly because of the belts not because of the gun itself, and even if Bofors was loaded by 4 or 5 rounds clips it could fire continuously if loaders did their job. Early in the war KM was handicapped by the fact that its 37mm was semi-automatic but on the other hand its muzzle velocity was clearly higher than that of Pom-pom and its mounting was stabilized on all tree axles. IMHO quadruple pom-pom was better weapon than KM’s twin 37mm, but latter also had its pros. And IMHO KM’s 20mm was better than RN’s quad .5. And the point was that early in the war RN DDs needed much more AA than KM’s DDs. Late in the war, especially those KM DDs which had got Barbara-upgrade had fairly powerful AAA, much more powerful than that of contemporary RN DDs and almost as good as contemporary USN DDs

And lastly, I’m wondering why, while accepting navweaps.comin critics on the AA capabilities of US and IJN 5” guns you seemed to ignore totally their opinion on RN 4.7” , namely “The lack of a DP function for these weapons was keenly felt throughout the war as more British destroyers were sunk by air attack than from any other cause. What little AA capability that these weapons did have was hindered by a lack of a tachymetric (predictive) fire control system and the setting of HE time fuzes by hand. “ Britain 4.7"/45 (12 cm) QF Mark IX

Juha


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## RCAFson (Aug 5, 2010)

Juha said:


> Hello RCAFson
> 
> 
> Juha



The RN often used heavy units of the fleet to escort convoys, and during these operations the Hunts could act as "fleet" destroyers. The RN also had a number of older battleships, that were slow enough for the Hunts to act as escorts. 

The RN .5" quad did have a larger ammo capacity than the USN .5" ( 200 rounds per gun versus about 100 ) which would increase its effective rate of fire, but the BMG was a pretty good gun. 

The RN introduced their version of the Dutch Hazemeyer mount in 1942. It featured twin 40mm bofors, triaxial stabilization, tachymetric fire control and type 282 radar. It was probably the most sophisticated mount used in WW2, but it was also said to be unreliable, so I wonder if it was really better than the old pom-pom?

The pom-pom had a mixed record on stoppages and some guns were nearly flawless, but it does seem to vary. Here's the pom-pom and 4.5in guns in action. Watch the shell bursts chase the Luftwaffe bomber
CONVOY TO RUSSIA - British Pathe
but as you can see, the 4.5" guns are not being fired at high elevation. Obviously, if these were 4.7" guns the rate of fire and effectiveness would be nearly identical. 

I don't ignore navweaps opinion on the 4.7" but I don't agree with some of what they say because a 40 deg elevation DP gun will be able to engage a wide variety of aerial targets, and if the RN fire control wasn't perfect, it was certainly better than nothing, and they did use it to shoot down aircraft. It also gained radar before everyone else. Regarding the fuse setting wikipedia states: 
_but all CP Mk XIX mountings were equipped with Fuze Setting Pedestals or Mk V Fuze Setting Trays...(3)
(3) Hodges and Friedman, Destroyer weapons of WW2, P95-96._
4.7 inch QF Mark XII - Wikipedia, the free encyclopedia


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## parsifal (Aug 6, 2010)

My two cents worth on some of the technical discussions occurring…..

i) HACs

Campbell is of the opinion that British HACs was better than barrage fire, but was still not as good as it should have been. Whilst the technical specs are a bit confusing to me, it seems it worked okay against aircraft flying straight, level and not too fast, but became progressively less as other variables were introduced. I think as a general statement US director control was superior, even the earlier pre-war models


ii)	the 5/38 was a better AA weapon than the 4.7, and in fact not all the mounts for the 4.7 could be claimed as even remotely DP. In many ways the 4.7 “DP” was similar in performance to the Japanese 5” “DP”. The AA ability of both was limited. 

However the superior AA performance of the 5/38 came at a rather severe penalty in range and perf0ormance when operating in the surface role. Given that a surprising number of surface engagements occurred, I am not so sure that the 5/38 did in fact represent the best compromise. Its strong points were its high rate of fire, quick traverse, and high elevation. 

iii)	At the beginning of the war, through to the latter half of 1942, the USN was actually mostly reliant on LAA that was less well developed than that in the RN. Their principal LAA weapon was not the Bofors, it was the 1.1” AA mount. At the beginning of the war the principal AA weapon in the RN was the 40mm Pom Pom, usually in multiple mounts. I have not heard before that it suffered large stoppages, and Campbell does not mention this in the details he provides. Some of the old timers I got to know thought it a satisfactory weapon, if a little heavy and short ranged. But it was superior in effective rate of fire to the 1.1” US gun though I don’t know anyone who used this weapon. 

I don’t think there is any measurable difference between the Vickers and the browning 0.5” at least none likely too make too much difference. But then 0.5” HMGs were very much second string equipment, only effective at keeping attackers some distance from their targets. Similar arguments can be mounted for nearly all weapons 20mm and below. Even the Japanese 25mm AA weapon was borderline in this respect. The old timers had a saying Time to hit the deck if the 20s open up….

With the introduction of the 40mm Bofors, nearly all other LAA armament became virtually obsolete. The US was fitted with this weapon well before the British and on a more lavish scale, so in that period 1943-1945 the USN held the advantage, in no small measure due to the lavish allocation of the Bofors to fleet defence. Once the RN started to receive the Bofors in substantial numbers (ie from ’45) the differences between the two navies effectiveness wise narrowed to virtually nothing. 

Iv)	Individually British light ships were les well equipped , but in the category of light forces (DDs and below) were far greater in numbers than in the USN, at least until the latter part of 1942, when the balance shifted in favour of the USN. US DDs tended to be larger and as a consequence were better equipped but there were less of them (until the end of '42).

Britain did develop reasonably efficient AA guns. The one most easily referred to is the 4.5”. This was a true DP gun, and having worked it myself, there were no obvious faults or drawbacks (admittedly when I trained on it in the ‘70s, it was obsolete, because it lacked an auto loader in the mounts we were using). This gun was fitted to a large proportion of the later war DDs. The Brits also built the LM class destroyers, which I believe had 4.5 in main armament. 

v)	Both navies found their arrangements for AA inadequate to fully deal with Kamikazes. The ad hoc counter to this was to beef up the AA defences on ships, particularly the 40mm Bofors numbers. This helped to curtail, but did not completely solve the threat posed by the Japanese Kamikazes.


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## Juha (Aug 6, 2010)

Hello RCAFson
On Hazemeyer, yes probably the most advanced and sophisticated AAA mount but rather heavy for its firepower and as you say, maintenance intensive, and often “sick”. IMHO US simple 40mm Bofors twin mount was a better option. Just like of RN postwar Bofors mountings the Mk 5 lived longer even if the STAAG mount was theoretically clearly better.

On the film had seen it before, and as it was shot during action against torpedoplanes of KG 26, its not surprising that firing angles were rather low. Even KM and Soviet Navy DDs could use their main armaments, 5” and 5.1” respectively, against torpedo planes.

On fuze setting, not bothering to look Wiki checked from my copy of Hodges and Friedman, according to it the Fuze-setting Machine Mk V was manual.

Of course RN AA arrangements were better than nothing but IMHO not very good, led down especially by the early HACS, which was after all the core of its long range AA defence, and quad .5”. Quad pom-pom wasn’t bad weapon but not excellent either. And its location on Tribals was rather bad, not being able to shoot to rear sectors and same time being somewhat wooded by the bridge, stacks and foremast in front sectors. 

Hello Parsifal
I agree with your analyze on HACS if you are talking on early versions.

Yes, RN 4.7” was optimized for surface use and IMHO 5”/38 was a better compromise for DD main armament. One reason for this was that RN had to halve the torpedo armament of its DDs to get even one proper HA gun onboard and torpedo was seen as a very important element of DD armament on those days.

On .5”s, not bothering check the specks but IMHO the difference was shown in the fact that when RAF found .303 mg inadequate, it never seriously thought adopting .5 Vickers but immediately after Browning .5 became available to it Spitfire wing was adapted to take one, the E Wing., and it began to install gun turrets with twin .5” Brownings.

If there was no big difference between .5” and 20mm why RN rushed to install 20mm guns in place of Quad .5” when 20mm became available? IMHO 20mm was a step forward but as planes came bigger and stronger also its usefulness diminished. As did that of 40mm, USN was moving to 3” when war ended.

Ls and Ms had 4.7” L/50 guns with 50deg max elevation fully covered mounts, one S had 4.5” fore guns as a test ship but first class to have 4.5” was the Z IIRC. Before that 4.52 was reserved to reconstructed BBs and to Renown and especially for carriers, which had 4.5” heavy AA from Ark Royal onwards, 8 twin mounts per ship. Army also used 4.5” AA guns.

And IIRC none of RN DDs had an AA armament of 5-6 real DP guns and 12-16 40mm Bofors plus many 20mm.as late war USN DDs had. But as you wrote many RN DDs were smaller ships that because desperate need for convoy escorts combined with run down capacity because of the Great Depression forced it to accept quantity over quality during early war years, when war ended, Battles and Darings were in pipeline and they had DP main armament backed up with numerous Boforses.

Juha


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## Juha (Aug 6, 2010)

Hello RCAFson
On Hazemeyer, yes probably the most advanced and sophisticated AAA mount but rather heavy for its firepower and as you say, maintenance intensive, and so often “sick”. IMHO US simple 40mm Bofors twin mount was a better option. Just like of RN postwar Bofors mountings the Mk 5 lived longer even if the STAAG mount was theoretically clearly better.

On the film had seen it before, and as it was shot during action against torpedoplanes of KG 26, its not surprising that firing angles were rather low. Even KM and Soviet Navy DDs could use their main armaments, 5” and 5.1” respectively, against torpedo planes.

On fuze setting, not bothering to look Wiki checked from my copy of Hodges and Friedman, according to it the Fuze-setting Machine Mk V was manual.

Of course RN AA arrangements were better than nothing but IMHO not very good, let down especially by the early HACS, which was after all the core of its long range AA defence, and quad .5”. Quad pom-pom wasn’t bad weapon but not excellent either. And its location on Tribals was rather bad, not being able to shoot to rear sectors and same time being somewhat wooded by the bridge, stacks and foremast in front sectors. 

Hello Parsifal
I agree with your analyze on HACS if you are talking on early versions.

Yes, RN 4.7” was optimized for surface use and IMHO 5”/38 was a better compromise for DD main armament. One reason for this was that RN had to halve the torpedo armament of its DDs to get even one proper HA gun onboard and torpedo was seen as a very important element of DD armament on those days.

On .5”s, not bothering check the specks but IMHO the difference was shown in the fact that when RAF found .303 mg inadequate, it never seriously thought adopting .5 Vickers but immediately after Browning .5 became available to it Spitfire wing was adapted to take one, the E Wing., and it began to install gun turrets with twin .5” Brownings.

If there was no big difference between .5” and 20mm why RN rushed to install 20mm guns in place of Quad .5” when 20mm became available? IMHO 20mm was a step forward but as planes came bigger and stronger also its usefulness diminished. As did that of 40mm, USN was moving to 3” when war ended.

Ls and Ms had 4.7” L/50 guns with 50deg max elevation fully covered mounts, one S had 4.5” fore guns as a test ship but first class to have 4.5” was the Z IIRC. Before that 4.5" was reserved to reconstructed BBs and to Renown and especially for carriers, which had 4.5” heavy AA from Ark Royal onwards, 8 twin mounts per ship. Army also used 4.5” AA guns.

And IIRC none of RN DDs had an AA armament of 5-6 real DP guns and 12-16 40mm Bofors plus many 20mm as late war USN DDs had. But as you wrote many RN DDs were smaller ships, that because desperate need for convoy escorts combined with run down capacity because of the Great Depression forced it to accept quantity over quality during the early war years, when war ended, Battles and Darings were in pipeline and they had DP main armament backed up with numerous Boforses.

Juha


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## BombTaxi (Aug 6, 2010)

A few words on the pom-pom;

While a powerful weapon, the RN realised early on that the massive smoke and vibration associated with 8 large weapons firing made optical aiming virtually impossible. The Pom-Pom Director was introduced in the late 30's, providing simple, non-tachymetric 'follow-the-pointer' direction to the layer and trainer on the mount. 

In 1940 it was superceded by the MkIV director, which included a GRU for tachymetric direction. However, it was not stabilised against the ship and therefore required a highly skilled crew to realise it's potential. 

HMS Prince of Wales went to her doom carrying the ultimate version of MkIV, equipped with RPC and linked to Type 282 radar. However, the size and weight of such installations meant that most DDs did NOT carry a Director at all, and relied on the crew aiming from a rolling, pitching, yawing and vibrating platform, through a cloud of their own smoke, right until the end of the war. I think that must be the definition of a weapon system getting in it's own way...


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## RCAFson (Aug 6, 2010)

BombTaxi said:


> In 1940 it was superceded by the MkIV director, which included a GRU for tachymetric direction. However, it was not stabilised against the ship and therefore required a highly skilled crew to realise it's potential.
> 
> However, the size and weight of such installations meant that most DDs did NOT carry a Director at all, and relied on the crew aiming from a rolling, pitching, yawing and vibrating platform, through a cloud of their own smoke, right until the end of the war. I think that must be the definition of a weapon system getting in it's own way...



AFAIK, the USN Mk 14 gyro sight and Mk51 director for the 40mm quad, was not stabilized either. The RN began to fit small directors on destroyers, but not until late in the war. Even with eye shooting the quad pom-pom would still have put a lot of shells into the air, and all axis destroyers relied on eyeshooting for their close range weapons.


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## RCAFson (Aug 6, 2010)

Juha said:


> Hello RCAFson
> 
> 
> On the film had seen it before, and as it was shot during action against torpedoplanes of KG 26, its not surprising that firing angles were rather low. Even KM and Soviet Navy DDs could use their main armaments, 5” and 5.1” respectively, against torpedo planes.
> ...



For a destroyer to engage aircraft, it has to have a FC system that can predict the aircraft movement and send the correct fuse timing to the guns, and KM and Italian destroyers could not do this. 

Here's a fuse setter from HMCS Haida:
http://hmcshaida.ca/4ingun_interior.jpg
HMCS HAIDA - Tour Stop 1

the fuze setter is connected to the FC computer which sends the fuse timing continuoisly until the load lamp lights and the shell is placed into the breech of the gun:


> _By moving his handwheel the plot operator sends away to the fuze setting receivers at the guns continual fuze numbers for the predicted future range of the aircraft. At the guns these fuzes are set when the " load " lamp lights at the receiver. The load lamp is worked automatically by the H.A. table at regular intervals, as is also the fire buzzer, which tells the director layer when to fire the broadside, whose shell are fuzed for the correct future range.
> _


The Gunnery Pocket Book - Part 4

Regarding the .5" Vickers, by late war the BMG was in mass production but the Vickers was quite a bit lighter than the BMG and would have been a better gun than the .303 BMG, IMHO.

The 4.7in twin was a "real" DP gun, but it was limited to 40 deg elevation. If you read accounts of Coral Sea and Midway actions, you will see that 4.7in twin armed destroyers could have engage the attacking aircraft throughout their attacks, either by directly engaging the attacking aircraft or by placing a barrage over the carriers.


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## BombTaxi (Aug 6, 2010)

RCAFson said:


> AFAIK, the USN Mk 14 gyro sight and Mk51 director for the 40mm quad, was not stabilized either. The RN began to fit small directors on destroyers, but not until late in the war. Even with eye shooting the quad pom-pom would still have put a lot of shells into the air, and all axis destroyers relied on eyeshooting for their close range weapons.



Putting a lot of shells in the air isn't particularly useful when they're not aimed. I think there is an opinion developing in this thread that RN AA must have been OK because it was better than the Axis equivalent. That is fair enough, but I still contend that it could have been better had more time and money been spent on it. It is clear from my reading though, that the RN did not take air attack seriously enough before the war, and paid a heavy price for this attitude once hostilities commenced. Phillips would not have taken Force Z into an area of Japanese air superiority with no carriers and limited AAA defence if he had had a serious appreciation of Japanese airpower and the threat it posed to capital ships...


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## RCAFson (Aug 6, 2010)

BombTaxi said:


> Putting a lot of shells in the air isn't particularly useful when they're not aimed. I think there is an opinion developing in this thread that RN AA must have been OK because it was better than the Axis equivalent. That is fair enough, but I still contend that it could have been better had more time and money been spent on it. It is clear from my reading though, that the RN did not take air attack seriously enough before the war, and paid a heavy price for this attitude once hostilities commenced. Phillips would not have taken Force Z into an area of Japanese air superiority with no carriers and limited AAA defence if he had had a serious appreciation of Japanese airpower and the threat it posed to capital ships...



Using eyesights is not as good as a director, but they are still aimed. AFAIK, USN destroyers didn't begin to get 40mm guns and directors until sometime in 1943, so they weren't that far ahead. 

The RN equipped their ships with the best AA weapons available before the war, and they certainly did not give up anything to the USN, in 1939 except in terms of DP weapons for destroyers, and even there they weren't that far behind.

Warspite 1939:
4 x twin 4"
4 x octuple pom-pom
4 x quad .5"

R class Battleships 1939
4 x twin 4"
2 x octuple pom-pom
2 x quad .5"

Colarado 1939
8 x 5" singles
4 - 8 x .5 MGs (hard to find exact info)

Ark Royal 1939
8 x 4.5" twin
4 x octuple pom-pom
8 x quad .5"

Enterprise 1939
8 × single 5 in/38 cal guns
4 × quad 1.1 in/75 cal guns
24 × .50 caliber machine guns

HMS Southhampton
8 × QF 4 in (100 mm) Mark XVI guns (4x2)
8 × QF 2-pounder (40 mm) Mark VIII pom-pom guns (2x4)
8 × .5 in (13 mm) Vickers machine guns (2x4)

USS Brooklyn 1939
8 × 5 inch/38 caliber guns (8x1)
8 × .50 caliber machine guns (8x1)

In 1939 the RN was ahead in terms of AA in every ship class, except, maybe destroyers. 

From what I gather, Philips didn't realize the IJN had long range TBs.


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## BombTaxi (Aug 6, 2010)

You've talked straight past my point again. I'm fully aware of the armaments of various USN and RN classes. I'm also aware that the USN didn't fit the 'magic' Bofors until later in the war. My assertion, about fifty posts back, was that the RN used sub-standard equipment early in the war, partly out of cost-saving, partly out of an under-appreciation of the threat posed by air attack. I'm not arguing it was better or worse than anybody else's equipment, just that it wasn't as good as it could have been and that this failure cost the RN dearly throughout the early phases of the war

I'm going to make this my last post in this thread, as it seems you will continue to claim that the RN had good AAA as it was no worse than anyone elses's...


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## RCAFson (Aug 6, 2010)

BombTaxi said:


> I'm not arguing it was better or worse than anybody else's equipment, just that it wasn't as good as it could have been and that this failure cost the RN dearly throughout the early phases of the war



The only thing that prevented the RN from covering their ships with far more HA guns, pom-poms and quad .5" was money...and the RN can't really be blamed for that! Sure they should have developed the 20mm and Bofors sooner, etc, but who was going to pay for it all? AFAIK, the RN outfitted their ships with the best AA in the world in 1939 despite the budget restraints.


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## parsifal (Aug 6, 2010)

guys, great debate, and very intersting, but we have strayed a lot off topic.......was the RN relatively successful or unsuccessful in fending off bomber, particulalry divebomber attacks. 

I did a bit more scratching around, and found that the 2 pounders were a bit problematic, apparently the quality of the ammunition and the cleanliness of the gun were important. This produced patchy results. During the attacks by FKX in January 1941, the illustrious expended over 30000 rounds of ammunition without stoppage, and shot down and drove off, a largte number of attackers. Conversely, during the PoW, Repulse debacle, Repulse expereienced numerous stoppages, which was attributed to faulty ammunition in the post action enquiry. In many actions the Pom Pom proved effective and vital to fleet defence, but sometimes it failed, with disatrous consequences. 


The RN estimated the Pom Pom to be about half as effective as the Bofors.

Returning to the Illustrious action, if she expended about 30000 rounds of ammunition defending against 30 aircraft, and destroyed 8 aircraft (a guess, based on the proportional numbers of a/c allocated to hit her....3/4 of 13 /c lost is 8-9, but estimate 1 or 2 shot down by the close escort) thyen she was expending about 3500 rounds per kill. Thats against Divebomber targets. Over germany at this time, the germans were expending around 8500 rounds per kill over germany at that time (based on figures by Westermann - Flak - German AA Defenses 1914-45) then even at this early date the vulnerability of Divebombers to flak was being exposed. By the end of the war, the USN estimated they were expending around 500-1000 rounds per kill, whilst the German flak defenses over Germany, after an improvement in 1942 (around 4500 rounds per kill, using highly trained crews and the best radar fc available to them had slumped to nearly 16000 rounds per kill, as a result of excessive barrel wear, relatively poorly trained crews (factory workers manninng flak guns part time are not as good as excperienced flak crews, and a shortage of rdf. even ammunitionthat was dubious at times. If Divebombers had been used over Germany in place of high altitude level bombers, the germans would have wiped the force off the map since the light flak units would have been able to engage as well, and the increased kill rates would have been disastrous.


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## Juha (Aug 7, 2010)

Hello RCAFson
Quote: “For a destroyer to engage aircraft, it has to have a FC system that can predict the aircraft movement and send the correct fuse timing to the guns…” 

I know the FKC system and doubt that it was even as good as HACS, otherwise RN would have put it and not bigger HACS on bigger ships, and early version of HACS were flawed, later marks and upgrades made it better and last versions were IMHO good as I have wrote earlier. And I have read the chapter of HA fire in Gunnery Pocket Book, 1945 version, earlier. I put the Hodges’ quote only to defend navweaps.com opinion because not being native English speaker to me “setting of HE time fuzes by hand” and using “manual Fuze-setting Machine Mk V for fuze-setting” is more or less same. To me by hand doesn’t mean that one was turning fuze using a wrench, having seen many film and having read Hodges and Friedman, were the working of the Fuze-setting Machine Mk V is explained. 

And again, if RN had thought that they had a passable DP system in their DDs they would never halved the torpedo-armament of their DDs just for to get ONE HA 3” or 4” gun onboard those DDs. OK in Tribals which had only a quad set anyway, they changed one twin 4.7” mount to one 4” mount. IMHO that reveal the state of AA defence of RN DDs, USN had only changed the mounts of their leaders which had had 5” LA mounts originally and IIRC some had both LA and HA 5” mounts during the war at least temporary.

Juha


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## RCAFson (Aug 7, 2010)

Juha said:


> Hello RCAFson
> Quote: “For a destroyer to engage aircraft, it has to have a FC system that can predict the aircraft movement and send the correct fuse timing to the guns…”
> 
> I know the FKC system and doubt that it was even as good as HACS, otherwise RN would have put it and not bigger HACS on bigger ships, and early version of HACS were flawed, later marks and upgrades made it better and last versions were IMHO good as I have wrote earlier. And I have read the chapter of HA fire in Gunnery Pocket Book, 1945 version, earlier. I put the Hodges’ quote only to defend navweaps.com opinion because not being native English speaker to me “setting of HE time fuzes by hand” and using “manual Fuze-setting Machine Mk V for fuze-setting” is more or less same. To me by hand doesn’t mean that one was turning fuze using a wrench, having seen many film and having read Hodges and Friedman, were the working of the Fuze-setting Machine Mk V is explained.
> ...



I can only say that FKC did work and it did shoot down aircraft and according to wikipedia FKC was used on cruisers and aircraft carriers:



> _It first appeared as the FKC Mk1 in destroyers of the 1938 Tribal class,[2] while later variants were used on sloops, frigates, destroyers, aircraft carriers and several cruisers.[3]
> (3) Naval Weapons of WW2, Campbell, p. 19_


Fuze Keeping Clock - Wikipedia, the free encyclopedia

. Late in the war the USN was bypassing their 5" FC computers in favour of the Mk51 gyro system, so I guess the USN had some problems too. AFAIK, the fuze timing was sent to machine fuze setters which could very quickly set the fuse and allow the guns to be loaded quickly, and RCN 4" twin mounts could achieve 15 to 20 rounds per minute using them. 


Lots of USN destroyers had 5" HA guns and/or torpedoes removed for more automatic AA:



> _Eventually, these Pacific ships received the same 5-inch and 40mm mount modifications as the Atlantic ships. In 1945, Lang and Sterett also landed their remaining torpedo tubes and their after 5-inch shields in favor of a total of four 40mm and four 20mm twins._


Benham-class destroyers in World War II



> _The original ships proved top-heavy and seriously lacking in anti-aircraft defense. The result was a proliferation of modifications.
> To reduce topweight, the No. 3 5-inch gun was landed on some ships, as had been done in preceding classes, leaving a total of four 5-inch/38s. The two quintuple torpedo tube mounts were retained on these ships—in some cases (e.g., Grayson) until 1945, when it was replaced by 40mm quad Bofors.
> Initially, six .50 cal. machine guns were added, bringing the total to twelve. Later, as they become available, 20mm single mounts replaced the 0.50 cal. machine guns, bringing these anti-aircraft armament of these ships in line with new 1941-42 construction_


Benson- and Gleaves-class destroyers — Four-gun modification

The fletcher class had 1/2 their torpedo tubes removed in favour of more AA:
Fletcher-class destroyers — 1945 anti-aircraft modification


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## Juha (Aug 8, 2010)

Hello RCAFson
Quote:” Late in the war the USN was bypassing their 5" FC computers in favour of the Mk51 gyro system, so I guess the USN had some problems too”

IIRC not even US was able to produce enough high-precision analogue computers, their navy and army expanding so much so fast.

Quote:” AFAIK, the fuze timing was sent to machine fuze setters which could very quickly set the fuse and allow the guns to be loaded quickly”

There was usually nothing wrong with Fuze-setting Machine Mk V, occasional tuning problems, but nothing that would not be overcome with good training. As I wrote, I only took a notice on it because IMHO Hodges and navweaps.com are in principal agreement on it.

Quote:” The fletcher class had 1/2 their torpedo tubes removed in favour of more AA”

The most important point here is, when that happened. RN was forced to halve the torpedo-armament, which was DDs main anti-shipping weapon against heavier ships and sometimes also against enemy DDs, in 1941, when KM still was enlarging its surface fleet, Fletchers lost their second TT bank in 45, when most of IJN’s surface fleet was sunk and in fact almost all what was left were floating at the harbours because of lack of oil. A big difference here.

Juha


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## Glider (Aug 8, 2010)

BombTaxi said:


> You've talked straight past my point again. I'm fully aware of the armaments of various USN and RN classes. I'm also aware that the USN didn't fit the 'magic' Bofors until later in the war. My assertion, about fifty posts back, was that the RN used sub-standard equipment early in the war, partly out of cost-saving, partly out of an under-appreciation of the threat posed by air attack. I'm not arguing it was better or worse than anybody else's equipment, just that it wasn't as good as it could have been and that this failure cost the RN dearly throughout the early phases of the war
> 
> I'm going to make this my last post in this thread, as it seems you will continue to claim that the RN had good AAA as it was no worse than anyone elses's...



I am afraid that I missed this thread which is a shame as its a topic that interests me. I would argue that no navy understood the threat from the air before the war as well as the RN. They had a number of actions in place pre war, to deal with the threat that were not matched anywhere else and *money was not the problem*.

The actions I am thinking of were:-
i) The conversion of old WW1 cruisers to AA cruisers giving them a vital front line role which paid many dividends.
ii) The building of the first AA Dido class cruisers. Until the Atlanta class came along they were unique
iii) The conversion of some merchant vessels to AA ships. These were probably the most extensive and complete conversion of any merchant ship to a naval fighting vessel anywhere, with firepower equal to any cruiser in the AA role.
iv) A number of VW class destroyers were altered to 4 x 4in DP guns as an escort.
v) The Hunt class destroyers with more punch to the ton than you will find anywhere
vi) Escort such as the Black Swan equal to any AA escort you care to mention
vii) The early selection of the 2pd as a weapon of choice for defending warships. It may not be as effective as the 40mm but pre war you will have difficulty fining a better weapon. A quad mounting on a destroyer was an effective defence
viii) The 0.5 was an ineffective weapon but the same mistake was made by most navies and the RN did replace them with 20mm as quickly as possible

The only major and I admit it was a major mistake the RN made was the lack of DP guns on destroyers. That said I believe a case could be made for saying that this wasn't a massive probnlem until Proximity fuses were developed. Hiitting an aircraft with heavy AA fire was very difficult before this. I would always put forward the case that 6 x 4in DP would have been far more effective than 4 x 4.7 LA. 

The difficulty that the RN had in increasing light AA fire wasn't in my view money or desire, it was space. People forget how much smaller RN destroyers were compared to other navies with the exception of the Italian navy.
The standard RN war built destroyer in standard tons was approx 30% smaller than the Fletcher, 20% smaller than the Yugumo and 40% smaller than the German destroyers.

To counteract this the RN tended to develop more sophisticated mountings to improve the effectiveness of the guns they carried. Twin 20mm were often in power operated mountings as were single 40mm guns and sighted using reflector sights. The twin Hazemeyer mounting was a step too far but being of a gyro stabalised mounting with built in radar direction and sight, it showed the lengths that they were trying to go to improve the situation. 
All these developments cost money so I would suggest the limitation was on deck space not cost


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## Juha (Aug 8, 2010)

Hello Glider
I agree almost all of your analyze, but IMHO 5.25" wasn't too good as AA gun, being too slow in traverse and elevation and having too heavy shell for high ROF. 4.5" would have been better armament for an AA ship but I understand the RN's selection, they thought that 4.5" shell would have been too light for surface fire for a cruiser size ship.
I also think that especially Hunts and those AA cruiser conversions were very good decisions. 

On heavy AA guns, IMHO the US system having one standard gun, 5"L/38 was better than that of RN's, still installing during the war 4", 4.5" and 5.25" heavy AA guns on their ships, partly because lack of production capacity for the newer guns, plus 4.7" for DDs, seems a bit like logistic nightmere.

IMHO the fact that RN emergency program DDs were smaller than those of most comtemporarys was a conscious decision to select quantity over quality, based on limited production facilities. And I agree with it, small DD was better than no DD. And those emergency DDs did well for ex. during the Battle of Barents Sea. But the fact remain that the Ts and Us of British Pacific Fleet were clearly weaker in AA and A/S weaponry than USN's Fletchers and Sumners, but as I wrote earlier RN had saw this and had Battles and Darings in pipeline.

Juha


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## Glider (Aug 8, 2010)

Juha said:


> Hello Glider
> I agree almost all of your analyze, but IMHO 5.25" wasn't too good as AA gun, being too slow in traverse and elevation and having too heavy shell for high ROF. 4.5" would have been better armament for an AA ship but I understand the RN's selection, they thought that 4.5" shell would have been too light for surface fire for a cruiser size ship.
> I also think that especially Hunts and those AA cruiser conversions were very good decisions.
> 
> ...


Hello Juha
I totally agree that the 5.25 was a better anti shipping weapon and less effective as an AA gun but at the time it probably seemed a good design and showed that the RN were taking the AA threat seriously.

Re the emergency destroyer program the design was based on the JK destroyer hull which was the latest pre war design and larger than most inter war british designs. Looking at it from that position it wasn't I believe a decision to settle for a smaller design, more the current design. They were no match for the Fletcher class but they had a respectable AA fire (apart from the DP weapons). Most were equipped for the Pacific with either a quad 2pd or a twin 40mm Hazemeyer mounting backed up by other weapons such as 4 x 40mm in single mounts or 8 x 20mm whilst keeping her 8 x TT. 
As we mentioned no match for the Fletcher but a fair comparison for the Benson class which was of a similar size.


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## RCAFson (Aug 8, 2010)

Juha said:


> IIRC not even US was able to produce enough high-precision analogue computers, their navy and army expanding so much so fast.
> 
> The most important point here is, when that happened. RN was forced to halve the torpedo-armament, which was DDs main anti-shipping weapon against heavier ships and sometimes also against enemy DDs, in 1941, when KM still was enlarging its surface fleet, Fletchers lost their second TT bank in 45, when most of IJN’s surface fleet was sunk and in fact almost all what was left were floating at the harbours because of lack of oil. A big difference here.
> 
> Juha



The USN was using the Mk51 for close range AA work, with the 5"/38 even when the same ship had the Mk37 system installed. Apparently, the Mk37 computer, which was very advanced, was also quite slow in forming a "solution".

I think it really shows that the USN did not face the same intensity of air attack as the RN, until late in the war.


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## Juha (Aug 8, 2010)

Hello RCAFson
I'd say IJN attacks during the Battle of Coral Sea, Midway, Santa Cruz etc were intensive, USN lost Lexington and Hornet sunk by air attacks, Yorktown badly hit at both first ones and in the end sunk by IJN sub at the end of BoM, Enterprise damaged and Hornet sunk at Santa Cruz.

Juha


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## RCAFson (Aug 8, 2010)

Juha said:


> Hello Glider
> I agree almost all of your analyze, but IMHO 5.25" wasn't too good as AA gun, being too slow in traverse and elevation and having too heavy shell for high ROF. 4.5" would have been better armament for an AA ship but I understand the RN's selection, they thought that 4.5" shell would have been too light for surface fire for a cruiser size ship.
> I also think that especially Hunts and those AA cruiser conversions were very good decisions.
> 
> ...



Elevation/traverse rates, deg/sec:

RN 5.25: 10/10 (most ships)
RN 5.25 RPC: 20/20 (Bellona class and Anson)
IJN 5": 6-12/4-6 (fixed angle loading so the gun had to be depressed and elevated again to load/fire.
IJN 5"/40 A1: 12/6-7 (Yamato and others mostly were A1, B1 very late war)
IJN 5"/40 b1: 16/16
RN 4.7" twin: 10/10
RN 4.5 twin: 10/15
RN 4.5 RPC: 20/20
KM 4.1" 10/8-8.5 (most common variants)
(data from navweaps.com)

so if the 5.25 was too slow in elevation and traverse, what does that say about axis AA guns?

However, the wikipedia article on the HACS states: "_6 degrees per second... was sufficient to track a 360 knot crossing target at a range of 2000 yards._" so it seems that 10 degs sec was adequate for most of the war.

There seems to be some disagreement about the ROF. The RN Pocket Gunnery Book says 10-12 rounds per minute per gun, which seems OK. The very long range and high MV would denote a flat trajectory which, along with the heavy shell should make it an effective AA gun. The USN, in 1945, began to introduce the 5"/54 which had a heavier shell and longer range than the 5"/38 and seems to be ballistically similar to the RN 5.25.


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## RCAFson (Aug 8, 2010)

Juha said:


> Hello RCAFson
> I'd say IJN attacks during the Battle of Coral Sea, Midway, Santa Cruz etc were intensive, USN lost Lexington and Hornet sunk by air attacks, Yorktown badly hit at both first ones and in the end sunk by IJN sub at the end of BoM, Enterprise damaged and Hornet sunk at Santa Cruz.
> 
> Juha



How many aircraft actually made it through the CAP to attack the USN carriers?


IJN attacking sorties: 
K = kate, V=Val , HLB = high level 

Coral Sea:18k,22v = about 40
Midway : 18v,(only 7 through CAP),10K(only 7 through CAP) = 14!
Santa Cruz: 22K, 18V (2-3 down by CAP) 12K, 20V, 9K, 4v 6HLB = about 90

so only Santa Cruz was a heavy attack, and it was split between two carrier groups

so three carrier battles = 144 IJN attack sorties, so about 1/2 of what the RN faced during Operation Pedestal alone, or PQ-18. alone.


data from Titans of the Seas, Belotte. This is pretty old, so newer books may be more accurate.


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## Glider (Aug 8, 2010)

RCAFson said:


> Elevation/traverse rates, deg/sec:
> 
> RN 5.25: 10/10 (most ships)
> RN 5.25 RPC: 20/20 (Bellona class and Anson)
> ...


A couple of things. 
i) The HACS system was quite good for what it was intended for ie defending against high altitude bombers. However experience proved that this wasn't the most dangerous threat, dive bombers and torpedo planes were the greatest danger.
ii) 6 degrees per second may well be sufficient to track a target but first you have to get your gun to point at the target before you can track it. I don't know if you have done any clay shooting but the speed is required to get the gun on the target, tracking is a lot slower. When facing more than one target the ability to change from one to another is critical
iii) Air attacks can continue for long periods and you will note that the 10-12 rpm was a target not achieved due to the design of the turret and the effort required which could not be sustained.


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## RCAFson (Aug 8, 2010)

Glider said:


> A couple of things.
> i) The HACS system was quite good for what it was intended for ie defending against high altitude bombers. However experience proved that this wasn't the most dangerous threat, dive bombers and torpedo planes were the greatest danger.
> ii) 6 degrees per second may well be sufficient to track a target but first you have to get your gun to point at the target before you can track it. I don't know if you have done any clay shooting but the speed is required to get the gun on the target, tracking is a lot slower. When facing more than one target the ability to change from one to another is critical
> iii) Air attacks can continue for long periods and you will note that the 10-12 rpm was a target not achieved due to the design of the turret and the effort required which could not be sustained.




10 degs/sec traverse was still better than most axis AA guns. It is only at very close ranges that traverse rates higher than a few degrees/sec are encountered, while closing targets on an attack course will have very low rates of elevation/traverse change. The RN was surprised sometimes, but they also had radar sooner than everybody else so that if an aircraft is detected at more than about 10000 yds the 5.25 would still have plenty of time to get on target.


The wikipedia article on the 5.25 has some things to say about ROF:
QF 5.25 inch Mark I naval gun - Wikipedia, the free encyclopedia



> The RN Gunnery Pocket Book published in 1945 states: _"These guns are combined High Angle and Low Angle Guns. The Mark II Mounting is found in all Dido class cruisers. The Mark I Mounting is found in King George V class battleships, where they fulfil the combined functions of H.A. Long Range Armament and Secondary Armament against surface craft. The main differences between the two mountings lie in the arrangements of the shellrooms and magazines, and the supply of ammunition to the guns. In this chapter, only the Mark II Mounting, as found in Dido class cruisers, is discussed. The 5.25 in. calibre with separate ammunition is used for dual High Angle and Low Angle Armament, since it gives the reasonable maximum weight of shell which can be loaded by the average gun's crew for sustained periods at all angles of elevation. The maximum rate of fire should be 10-12 rounds per minute."_[2][3] A wartime account describes HMS Euryalus firing her 5.25 in guns: _"We left Suez and headed for the Gulf, where at 1PM the ship's company closed to action-stations and gave a demonstration of the cruiser's fire power to the army officers. Fire was opened with the 10 5.25" guns in the form of a low angle barrage accompanied by fire from smaller guns. Set to burst at 2000 yds range, a terrific barrage was put up for two minutes and we fired some two hundred rounds of 5.25-inch HE_
> 
> (2) The Gunnery Pocket Book. 1945. p. 51. The Gunnery Pocket Book - Part 1.
> (3) Sired, Enemy Engaged, p63.
> (4) Sired, Enemy Engaged, p23, states: "_The Italians did not press home their attacks very hard and I thought they had a lot to put up with, as each (10 5.25 in gun) cruiser could fire 100 rounds of 5.25" HE shell per minute..."_ Ronald Sired was a gunnery petty officer onboard HMS Euryalus. The accuracy of Sired's account was praised by Captain FC Flynn RN. Official Historian of the Naval Campaigns in the Mediterranean.


 
So it seems that 10 rounds per minute per gun was achieved in combat, which matches the 10-12 rounds per minute stated in the Pocket Gunnery Book.


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## RCAFson (Aug 8, 2010)

Found this on wikipedia:

Prince of Wales engaging TBs during Operation Halberd, with her 5.25in guns:
WITH THE NAVY - British Pathe
note the low angle of elevation of the 5.25" guns.



> _ ... Prince of Wales was credited with several 5.25 inch kills during Operation Halberd,[101] and damaged 10 of 16[102] high level bombers in two formations during her last engagement... _



(101)Allied Battleships in WW2, Garzke and Dulin, p. 191
(102) Garzke and Dulin. Allied Battleships in WW2. pp. 195, 206–207.

This is another video of a convoy battle, at about 1:03, watch the shells chase the TB:
MALTA CONVOY - FURTHER PICTURES - British Pathe


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## Juha (Aug 8, 2010)

Hello RCAFson
Navweps says that for 5.25” 10-12 ROF was designed but 7-8 actual.
Now US 5”/38 had vastly superior rates and ROF and even US 5”/51 had better rates and ROF
Also 4.5” had better ROF, how much better difficult to say because AA cruisers would have had the same Mk III UD like WWII Ark Royal, my copy of Ark Royal book might have the answer but I don’t have time to dig that out, same elevation but 50% better train rate.

Santa Cruz, the first attack, inside AA range: 16 dive-bombers, of which one was badly dam and 18 torpedo-planes, of which one badly dam. 2nd attack, 18 dive-bombers and 15 torpedo-bombers. 3rd attack 17 dive-bombers.

And from memory, Midway: 12-15 dive-bombers and 10 torpedo-bombers, Coral Sea more, probably even more than during the first two attack at Santa Cruz because the attackers came to same carriers which were bigger than Midway’s Hiryu and USN fighter control had learned lessons from Coral Sea, Midway and Eastern Salomons.

Juha

ADDITION: On Midway, 10 VTs got inside AA-fire but some Wildcat followed them there, claimed 3 one Wildcat shot dowm/badly dam by own AA fire. Now fighter pilots claimed those 3 and said that AA fire was inaccurate, and guess what naval gunners said? Jap VBs at Midway, 7 might be right but that means to take more or less by face value of F4F pilots claims, the attack consisted 18VBs, 10VTs and 6 VFs(Zeros). And Japanese were more deadly than anybody else in 1941-42, the first 6 Vals that attacked Hornet got 3 hits. Also USN AA at Santa Cruz was deadly, especially that of TF 16.

2nd ADDITION, you are counting apples and oranges, At Coral Sea the first attack by Shohaku and Zuikaku, which instead of finding US carriers, found Naval oiler Neosho and DD Sims, both of which were sunk, 2nd attack was clearly smaller one, only most experienced VT crews, IIRC correctly 18 VTs , didn't found US carriers, dumped their torpedos and on return journey overflow US TF in the darkness and suffered losses. Next day the main attack, my First Team is in attick but according to Rohwer and Hummelchen consisted of 90 a/c. So IJN flew at least say 150 attack sorties during those 2 days. 
CORRECTION: Contrary to my habits checked Wiki article on the Battle of Coral Sea, which seemed to be good, at least sources are good, so IJN carrier planes flew 78+27+69 attack sorties=174 attack sorties there.


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## RCAFson (Aug 8, 2010)

Juha said:


> Hello RCAFson
> Navweps says that for 5.25” 10-12 ROF was designed but 7-8 actual.
> Now US 5”/38 had vastly superior rates and ROF and even US 5”/51 had better rates and ROF
> Also 4.5” had better ROF, how much better difficult to say because AA cruisers would have had the same Mk III UD like WWII Ark Royal, my copy of Ark Royal book might have the answer but I don’t have time to dig that out, same elevation but 50% better train rate.
> ...




The RN states 5.25 ROF of 10-12 and a first hand account from an RN gunner states 10 rounds/minute. Navweaps states 12 RPM for 4.5in. Maybe Navweaps data is out of date?

Your figures for attacks seem to match mine pretty closely and I edited my post to include the numbers of attacks, and the total for all 3 actions was about 145.


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## RCAFson (Aug 8, 2010)

Juha said:


> ADDITION: On Midway, 10 VTs got inside AA-fire but some Wildcat followed them there, claimed 3 one Wildcat shot dowm/badly dam by own AA fire. Now fighter pilots claimed those 3 and said that AA fire was inaccurate, and guess what naval gunners said? Jap VBs at Midway, 7 might be right but that means to take more or less by face value of F4F pilots claims, the attack consisted 18VBs, 10VTs and 6 VFs(Zeros). And Japanese were more deadly than anybody else in 1941-42, the first 6 Vals that attacked Hornet got 3 hits. Also USN AA at Santa Cruz was deadly, especially that of TF 16.



The 40mm gun made it's first appearance, in large numbers at Santa Cruz, but also the USN ships had a lot more 20mm guns by then as well, IIRC. IJN DBs might have been more accurate but Luftwaffe DBs were dropping 500kg bombs. Given equivalent numbs of ships, IMHO RN AA would have been more effective against IJN attacks at Coral Sea and Midway simply because there would have been a lot more barrels firing.


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## Juha (Aug 8, 2010)

Hello RCAFson
I have no opinion on Coral Sea and on Midway (not time to check comparable real results) but Lundstrom's The First Team and the Guadalcanal Campaing says that at Santa Cruz USN AA shot down 25 japanese planes and USN a/c 29. IMHO at that time US AA was more effective than RN AA

Juha


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## Juha (Aug 8, 2010)

Hello RCAFson
on dive bombers, yes I agree that while in 41-42 IJN was unsurpassed in accuracy the Ju 87 could drop clearly more heavy bombs than Val. On the other hand also IJN carrier torpedo bomber crews were very good, much better than LW crews and better than Italians in spite of the very succesful attack on PQ 18 by KG 26, after all during that attack the merchantmen forgot evasive manoeuvres in the heat of battle, something that USN and RN ships didn't forgot even if PoW's first manouvre was a badly thought out and after that it could not manoeuvre much.

Juha


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## Juha (Aug 8, 2010)

Hello
checked from Lundstrom, at Midway one of Hiryu's 10 VTs was shot down before AA opened fire, 2 F4Fs were shot down inside the escort screen, one by a Zero and one was claimed by a Kate gunner but the US pilot thought that he was shot down by naval AA, and F4Fs got 11 Vals before they dived according to Lunstrom, my old source says 10.


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## RCAFson (Aug 8, 2010)

Juha said:


> Hello RCAFson
> I have no opinion on Coral Sea and on Midway (not time to check comparable real results) but Lundstrom's The First Team and the Guadalcanal Campaing says that at Santa Cruz USN AA shot down 25 japanese planes and USN a/c 29. IMHO at that time US AA was more effective than RN AA
> 
> Juha



I decided to compare the AA of USN and RN ships in Oct 1942, using actual USN ships in 1942 at santa Cruz and equivalent RN ships, in Oct 1942:

According to US Battleships, (googlebooks) South D. had 4 x quad 40mm, 4 x quad 1.1", and about 50 20mm.
Enterprise had 8 x 5", 4 quad 40mm, 1 quad 1.1", 44 20mm
Hornet had 8 x 5" 5 x quad 1.1", 32 20mm

In October 1942 Howe or Anson would have had 16 x 5.25, 6 x octuple pom-pom, 18 x 20mm.
Indomitable or Victorious would have had 16 x 4.5", 6 x octuple pom-pom and 10-12 20mm.

Capital ships:

RN: 16 x 5.25in, 32 x 4.5" 18 x octuple pom-pom, 40 20mm = 48 x DP guns, 144 40mm pom-pom, 40 20mm = 48 x DP and 184 AAA

USN: 24 x 5", 8 x quad 40mm, 10 x quad 1.1" 126 20mm = 24 DP guns, 72 40/1.1", 126 x 20mm = 32 x DP and 196 AAA

3 x Atlanta ckass cruisers: 16 x 5"/38 2 x quad 1.1" 8 x 20mm = 48 x DP and 48 AAA
3 x Dido class 10 x 5.25", 2 x quad pom-pom, 4 or 5 x 20mm = 30 x DP and 38 AAA



2 x USN heavy cruisers with 4x 5", 12 x 20mm (?) can't find exact info on Northampton and Pensacola
1 with 8 x 5" 4 x quad 1.1" 12 x 20mm = 16 x DP and 52 AAA

typical RN heavy cruiser:
2 with 4 x twin 4", 2 octuple pom-pom 5 20mm
1 with 4 x twin 4", 2 x quad pom-pom, 5 20mm = 24 DP and 55 AAA

USN Destoyers 7 with 5 x 5"/38 and 4 x 20mm
7 with 4 x 5", 1 quad 1.1" 4 x 20mm (typical mix) = 63 DP, 115 AAA

RN Destroyers:
6 with 6 x 4.7" 1 x 4" HA, 1 quad pom-pom, 4 x 20mm
6 with 4 x 4.7" 1 quad pom-pom, 6 x 20mm.
2 with 5 x 4", 1 quad pom-pom, 6 x 20mm = 76 DP, 118 AAA

Various websites for data.

*RN Totals = 178 DP and 395 AAA of which 268 are 40mm pom-pom

USN totals = 159 DP and 411 AAA of which 32 are 40mm bofors. 

I would say that the RN was still ahead of the USN in Oct 1942. 
*


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## Glider (Aug 9, 2010)

RCAFson said:


> The RN states 5.25 ROF of 10-12 and a first hand account from an RN gunner states 10 rounds/minute. Navweaps states 12 RPM for 4.5in. Maybe Navweaps data is out of date?
> 
> Your figures for attacks seem to match mine pretty closely and I edited my post to include the numbers of attacks, and the total for all 3 actions was about 145.



I think that you are being a little selective over your quotes from Navweapons. On the 5.25 it also states:-

_Unfortunately, the design of the gunhouse was cramped and the heavy projectile and cartridge cases resulted in a lower rate of fire than expected. In addition, the slow elevating and training speeds of the mounts were found to be inadequate for engaging modern high-speed aircraft. _

_1) As designed, the expected rate of fire for these guns was 10 - 12 rpm. However, the heavy weight of the projectile and cartridge case plus the semi-automated fuze setting mechanism meant that this round required much crew handling before it could be rammed into the breach. The tight design of the gunhouse also interfered with the smooth crew operation necessary to achieve high rates of fire. _

_The mountings used on the King George V and Dido classes were very cramped and difficult to maintain. They were also difficult to train in the non-powered mode using the hand mechanisms. Their rather slow training speeds meant that they could not track fast-moving aircraft. These last two problems were highlighted during the Japanese attacks on HMS Prince of Wales. When she took up a 10-11 degree list as a result of damage received, it was found that some of the mounts could not be trained to engage the succeeding attacks_
Remember my comments on the ability to switch targets being critical?

On training speeds the question that should be asked is 'If 10 deg/sec is sufficient why did the RN modify the 4.5in mounts to increase change rates from 10 to 20 deg/sec

Also I don't understand your comparison figures in the previous posting. Can you tell me how you calculated them.
Thanks


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## RCAFson (Aug 9, 2010)

Glider said:


> I think that you are being a little selective over your quotes from Navweapons. On the 5.25 it also states:-
> 
> 1) _Unfortunately, the design of the gunhouse was cramped and the heavy projectile and cartridge cases resulted in a lower rate of fire than expected. In addition, the slow elevating and training speeds of the mounts were found to be inadequate for engaging modern high-speed aircraft. _
> 
> ...



1) As I said previously, the RN and an RN 5.25iin gunner states that the 5.25in ROF is 10-12 rounds/minute/gun:
QF 5.25 inch Mark I naval gun - Wikipedia, the free encyclopedia Navweaps or the RN...guess who I believe more?

10deg/sec training rate is sufficient to track WW2 era aircraft. This is a simple fact and easy to verify with a protractor and some paper. The 5.25 is a long range AA gun and at 5000 yards, a 270 knot target will have maximum rate of bearing change of 1.7 degs/sec.

2)The 5.25 round weighed 80 lbs and used the same fuse setters as the 4.5 and 4" guns. The 4.5 twin (also a very cramped turret by the look of it) had a ROF of 12 r/m and the 4in 15-20 r/m. Who ever wrote the navweaps article is being illogical, as the crew handling is really no different than other RN DP weapons. The shell is placed in a fuze setter and then into the loading tray, exactly the same as the 4.7in and 4.5 twin turrets. 

3) The ability of the 5.25 turret to operate without power and with a 10-11 degree list is not relevant. Would any turret operate under such conditions?

4) Sure higher is better, but for the vast majority of cases 10 degs/sec is sufficient. If it wasn't sufficient then I guess no Axis navy had any DP AA capability. Think about that for second. Also with VT ammo 20degs/sec might prove useful for very high speed, close range targets that didn't exist in 1940. 

5) The USN had 1 battleship, 2 carriers, 3 heavy cruisers. 3 AA cruisers and 14 destroyers at Santa Cruz. I calculated the number of guns of each calibre for these ships and for an equal number of equivalent RN ships from the same time frame (Oct 1942).


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## Juha (Aug 9, 2010)

Hello RCAFson
on 4.5” on NavWeaps.com, Mk III UP might well had higher ROF than that of Mk II BD because being with openbacked shield there should have had a bit more room for the crew to work.

On Force Z, IMHO 5.25” didn’t do especially well, they didn’t succeed broke the tight formations of IJNAF level bombers which got one hit on Repulse during the first attack and didn’t hinder IJNAF torpedo bombers, which got 1-2 hits on PoW during their first attack, after which part of 5.25” were knocked out and PoW was practically out of fight, waiting for coup de grace. IIRC IJNAF lost only 3 planes during the attacks, 2 of which were allocated to pom-pom on the B-turret of Repulse during the last attack. Now AA of one BB + One BC + 3 DDs shoot down 3 planes and the planes got some 9-11 torpedo hits and 2 bomb hits on 2 RN capital ships.

Compare to on 9 March 1942 Tirpitz was attacked by the strike force of 12 torpedo-carrying Albacores under the command of Lieutenant-Commander W. J. Lucas from the aircraft carrier Victorious. The attack failed and 2 Albacores was shot down. Tirpitz was escorted by 4 DDs. Now Albacore was a different plane than Nell or Betty and numbers are different and Tirpitz had aircover by one of its Ar 196 float planes but after all one of Repulse’s Walrus was also around Force Z but didn’t try to interfere like the Arado crew did. Apples and oranges but still IMHO German naval AA did better than that of Force Z. Only conclusion one can draw on those 2 combats IMHO is that KM’s AA wasn’t hopeless.

On your comparison on AA, first of all, USN carrier defence was based on fighters, RN's originally on AA. So US carriers carried more fighters, RN carriers more AA and newest one had armoured flight decks. So it rather odd to give heavy weight to carriers AA and leave fighters off, unless one wants to give some advantage to RN and to the idea that carrier's best defence is its AA not its planes.

On heavy cruisers, standard USN treaty cruiser AA suit was at the beginning of the Pacific War 8 single 5”/25s, Pensacolas and Northamptons had had the number of their 5”s increased to 8 in late 30s. All New Orleans, Pensacolas and Portlands had 4 quad 1.1” plus up to 12 20mm already in Aug 42. Also Northamptons had some quad 1.1”s and some 20mm.

And after all even RN thought than twin Bofors was better than quad pom-pom, now obviously USN thought that twin Bofors was better than quad 1.1” but how to compare quad pom-pom to quad 1.1”, especially when opinions differed widely on quad 1.1”, but generally it wasn’t liked.
And on heavy AA, here the quality of predictors was crucial, so counting the barrels is rather meaningless.


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## Shortround6 (Aug 9, 2010)

RCAFson said:


> 1) As I said previously, the RN and an RN 5.25iin gunner states that the 5.25in ROF is 10-12 rounds/minute/gun:
> QF 5.25 inch Mark I naval gun - Wikipedia, the free encyclopedia Navweaps or the RN...guess who I believe more?



Lets see, the HMS Euryalus manages to demonstrate 10rpm while firing with zero change in elevation,zero change in training and zero change in range when fresh out of harbor and in calm seas in view of shore.
What happened to the 12 rounds per minute?
What happens when the turret is moving in train, the guns are changing elevation, the fuse settings keep changing and the deck is rolling and pitching? rate of fire speeds up




RCAFson said:


> 2)The 5.25 round weighed 80 lbs and used the same fuse setters as the 4.5 and 4" guns. The 4.5 twin (also a very cramped turret by the look of it) had a ROF of 12 r/m and the 4in 15-20 r/m. Who ever wrote the navweaps article is being illogical, as the crew handling is really no different than other RN DP weapons. The shell is placed in a fuze setter and then into the loading tray, exactly the same as the 4.7in and 4.5 twin turrets.



the round did not weigh 80lbs, the projectile weighed 80lbs. + the 41lbs of charge and cartridge case.
the 4.5 weighed 55lbs plus 38.5lbs of charge and cartridge case. the early mountings used a fixed round that combined both weights together. By the way the early twin mounts in the big ships did not have ammunition hoists that came into the mounts. the ammunition hoists/conveyors were outside the mounts and crew men took the rounds from the hoists/conveyors and placed them in two scuttles on the rear of the mount. distance the rounds had to moved from the hoist to the scuttles changed as the mount rotated.
the 4" used only a fixed round that weighed 63.5lbs. 




RCAFson said:


> 5) The USN had 1 battleship, 2 carriers, 3 heavy cruisers. 3 AA cruisers and 14 destroyers at Santa Cruz. I calculated the number of guns of each calibre for these ships and for an equal number of equivalent RN ships from the same time frame (Oct 1942).



Except you made a few mistakes and/or fudged a few things. 

you left out the South Dakotas 20 5in guns or only counted them as 8 guns?
Hornet CV 8the one at Santa Cruz had eight 5 in guns. 
Enterprise had eight also. 
total is 36 not 24. 

Both US cruisers had had their 5"/25s (not really dual purpose but dedicated AA guns) doubled to 8 per ship after being built but pre war.
16 guns instead of 8. 
so US total for heavy cruisers is 24, same as the British. 

No argument with the AA cruisers. 

As for the 76 DP guns on the British destroyers, I think you are being more than a bit optimistic.
The twin 4.7 had the elevation problem of 40 degrees, why don't you get out your pencil and paper and protractor or better yet some trig tables. 
of from the Wiki page on the 5.25" gun.
" Hodges, Tribal Class Destroyers, p32: Diagram of High Level Bomber Attack: A 240mph target, at 12 thousand feet altitude could expect to be under for fire about 75 seconds, from the time it enters the effective range of the HACS until it flies to within the minimum range of a 5.25 gun elevated to 70 degrees. A Tribal class destroyer would be able to engage the same target for about 37 seconds."
Please note that the minimum range for the 4.7 would be at a much longer distance than the 5.25". In fact (if I have done the math right) the 240mph target at 12,000ft would be safe from a 4.7in armed destroyer once it got within 4768yds of it. 
The J class (and follow ups) had inferior AA fire control to the Tribals for the 4.7s.
As for the 4in gun that replace the bank of torpedo tubes, it wasn't connected to anything. It depended on the gun captain's squinty eye for range, speed , altitude and course. It also depended on his wetted finger held up for atmospheric conditions data (doesn't work to well on a moving destroyer). And depended on the aimer and trainers cartwheel sights for final aiming. 
The 4.7s on the Os and Ps (those that had them) were hand worked and not power worked. 
The were fitted with 4 single 20m as completed and were later changed (in most) to 2 singles and 2 twins for 6 barrels. 
The Q and R classes did get the better "tribal" AA director set up but the guns were essentially unchanged from the H class if not earlier. 

Of course if your really want to disagree with my assessment of the 4.7" guns as dual purpose you could always claim that the the 8" guns on the British cruisers were dual purpose because of their 70 degree elevation, of course they have that fixed loading angle down at 10 degrees that you complain about with the Japanese ships. 
The Japanese also provided AA shells even for battleship guns but that doesn't really make them true AA guns or dual purpose does it?

The British early 4.7s may have been called dual purpose but they weren't even really fooling themselves about it.


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## Glider (Aug 9, 2010)

RCAFson said:


> 1) As I said previously, the RN and an RN 5.25iin gunner states that the 5.25in ROF is 10-12 rounds/minute/gun:
> QF 5.25 inch Mark I naval gun - Wikipedia, the free encyclopedia Navweaps or the RN...guess who I believe more?


I think shorthounds posting covers this point.



> 10deg/sec training rate is sufficient to track WW2 era aircraft. This is a simple fact and easy to verify with a protractor and some paper. The 5.25 is a long range AA gun and at 5000 yards, a 270 knot target will have maximum rate of bearing change of 1.7 degs/sec.


Something I have never disagreed with. What I have said is that switching from one target to another is critical. A point you have not adressed



> 2)The 5.25 round weighed 80 lbs and used the same fuse setters as the 4.5 and 4" guns. The 4.5 twin (also a very cramped turret by the look of it) had a ROF of 12 r/m and the 4in 15-20 r/m. Who ever wrote the navweaps article is being illogical, as the crew handling is really no different than other RN DP weapons. The shell is placed in a fuze setter and then into the loading tray, exactly the same as the 4.7in and 4.5 twin turrets.


Now I must ask who do I prefer to believe. An article written by an organisation that specialises in this topic, or yourself who has written the article off as being illogical without any evidence. Who would you prefer?



> 3) The ability of the 5.25 turret to operate without power and with a 10-11 degree list is not relevant. Would any turret operate under such conditions?


Because ships get damaged and power can fail in combat.



> 4) Sure higher is better, but for the vast majority of cases 10 degs/sec is sufficient. If it wasn't sufficient then I guess no Axis navy had any DP AA capability. Think about that for second. Also with VT ammo 20degs/sec might prove useful for very high speed, close range targets that didn't exist in 1940.


I didn't ask if higher is better, I asked WHY would they make the change. After all it would involve slowing production, taking design experts from other areas of development. You don;t do this in a war without a very good reason. The questions stands Why did the RN make the change.
Of course the Japanese had DP guns no one is saying they didn't and the comment about close range targets didn't exist in 1940 I take to be a joke, you are kidding right?


> 5) The USN had 1 battleship, 2 carriers, 3 heavy cruisers. 3 AA cruisers and 14 destroyers at Santa Cruz. I calculated the number of guns of each calibre for these ships and for an equal number of equivalent RN ships from the same time frame (Oct 1942).



Thanks for this, as others have pointed out you have made some errors on this.


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## Nikademus (Aug 9, 2010)

Juha said:


> Hello
> checked from Lundstrom, at Midway one of Hiryu's 10 VTs was shot down before AA opened fire, 2 F4Fs were shot down inside the escort screen, one by a Zero and one was claimed by a Kate gunner but the US pilot thought that he was shot down by naval AA, and F4Fs got 11 Vals before they dived according to Lunstrom, my old source says 10.



Hi Juha,

Here's what i garnered from Lundstrom:

Ok. here's the AA breakdown: 

Coral Sea 

Over Shoho: 

none

Over Shok and Zuik 

1 x SBD 

Failed Dusk attack near USN TF 5/7/42 

1 x D3A 

Over Lex and York 

2 x B5N 
1 x D3A 

Over Neosho and Simms 

1 x D3A 

Midway 

Over Kido Butai 

1 x A6M (friendly fire) 
possibly 1 x B-26 
1 x SBD 

Over Tanikaze 

1 x SBD 

Over Mikuma/Mogami 

2 x SBD 

Over Yorktown 

2 x D3A 
2 x B5N 

Eastern Solomons 

Over Ryujo 

zip 

Over Enterprise 

1 x F4F (friendly fire) 
4 x D3A 

(no B5N's attacked) 

Santa Cruz 

Over Shok and Chukuma 

possibly 1 x SBD (Lundstrom is unclear here) 

Over USN TF's 

14 x D3A 
11 x B5N 

These figures represent immediate losses directly attributed to AA. They do not include damaged planes that ditched or were written off. It should also be noted that AA may have contributed in the loss of some Japanese bombers scored by USN fighters. 

As mentioned, prior to Santa Cruz, USN AA *wasn't* really more effective vs. aircraft than the typical RN experience when it came to outright losses. The differential begins at Santa Cruz and can be directly attributable to the upgrading to large numbers of 20/40mm mounts. King Board AA upgrades helped but war experience showed way more and better AA was needed.

The Force Z experience must take into account the early crippling of PoW by a hit in the worst place imaginable which also took out the majority of her powered AA and imparied her speed and maneuverability. The biggest lesson the RN drew from the experience (besides the confirmation that aircraft were not the dominant weapon...capable of sinking even a modern capital ship...manned and at sea, ready for attack), was the need for redundant power and auxillery power backup.


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## Glider (Aug 9, 2010)

I think its worth mentioning that the HACS worked to some degree over Force Z despite the problems. If I remember correctly a high proportion of the high level bombers were damaged and had to abandon the original plan for them to attack twice.
Could be wrong on this but its something that I recall


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## parsifal (Aug 9, 2010)

HACs did work, but the AA effort over Pow Repulse was not one of the better AA moments for the RN. There were continual stoppages in the 2 pdrs, and the 5.25s had problems as previously alluded to. I dont think ther was any impedeiment to the Japanese preparing a second strike. 3 aircraft were lost, and 9 damaged to varying degrees.

There were times when RN AA produced some very fine results, such as over the Illustrious in 1941 and Fijis effort off Crete (though she was sunk after running out of ammunition) but the PoW and Repulse episode is not one of those Kodak moments


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## RCAFson (Aug 9, 2010)

Juha said:


> Hello RCAFson
> on 4.5” on NavWeaps.com, Mk III UP might well had higher ROF than that of Mk II BD because being with openbacked shield there should have had a bit more room for the crew to work.
> 
> On Force Z, IMHO 5.25” didn’t do especially well, they didn’t succeed broke the tight formations of IJNAF level bombers which got one hit on Repulse during the first attack and didn’t hinder IJNAF torpedo bombers, which got 1-2 hits on PoW during their first attack, after which part of 5.25” were knocked out and PoW was practically out of fight, waiting for coup de grace. IIRC IJNAF lost only 3 planes during the attacks, 2 of which were allocated to pom-pom on the B-turret of Repulse during the last attack. Now AA of one BB + One BC + 3 DDs shoot down 3 planes and the planes got some 9-11 torpedo hits and 2 bomb hits on 2 RN capital ships.
> ...



The RN 4.5 BD turret could maintain 12 r/m for long periods:



> # QF Mark III: same as Mark I, except for firing mechanism. Was fitted in twin mountings BD Mark II, BD Mark II** and BD Mark IV. HMS Illustrious fired about 3000 rounds of 4.5" ammunition, at an average of 12 rounds per gun per minute, during one prolonged action in January 1941.[3]
> (3)Naval Weapons of WW2, Campbell, p17


QF 4.5 inch Mk I ? V naval gun - Wikipedia, the free encyclopedia

The 5.25 forced two bombers to abort and damaged 10 of 16, even though they were the only effective HA guns in Force Z. Repulse had a total of 4 x 4" and none of the destroyers had an AA FC system.

I don't understand, you are arguing that KM AA wasn't hopeless, yet Tirpitz's 4.1in guns had a slower traverse than the RN 5.25in.

This discussion is about AA capability. So agree that RN was ahead in AA capability in Oct 1942?

I could find any info on two of the older heavy cruisers, but even if we increase the AA as per your post above, it really doesn't change the over all picture.

All the RN capital units had the latest versions of HACS and tachymertic pom-pom directors with radar. I doubt there is any difference in FC, and for the AAA the RN is probably ahead.


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## RCAFson (Aug 9, 2010)

Nikademus said:


> Hi Juha,
> 
> Here's what i garnered from Lundstrom:
> 
> ...




Thanks for the AA totals but how did you conclude that RN AA was less effective? Force Z really only had one effective modern ship with minimal capability in Repulse and still did as well as the entire USN force at Midway or Coral Sea. If Force Z had had 3 modern destroyers and a modern ship like Renown, it would have done much better, as the RN was doing while defending convoys such as PQ-18.

I think there is every probability that an equivalent RN force could have matched or bettered the USN AA kills at Santa Cruz, simply because they would have more 40mm calibre AA combined with effective radar equipped tachymetric directors.


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## Juha (Aug 9, 2010)

Hello Nikademus
thanks for you analyze, all that I can add that also at Santa Cruz USN had first time a BB screening a CV but I agree that that was only one of the factors that contributed to dramatic improvement in AA rffectiveness. Also IMHO in the Fist Team Lundstrom underestimate the effectiveness of US AA, accepting too easily pilots’ opinion. In The First Team and The Guadalcanal Campaign he is more objective in pilots’ claim vs AA claims question. But any way at most one could add one Val and 3-4 Kates to Midway AA kills around Yorktown.

Hello Gilder
On Force Z, IMHO the number of lightly damaged a/c isn’t important, what counts is how many had to abort the attack. I cannot remember reliable info on that. For the plus side IMHO one can add a fourth plane to AA kills, that was the plane which was badly damaged and crashed on landing at Saigon. On the minus side, IIRC, it is decades ago when I read this, that 2 of the 3 kills around the ships were allocated to the pom-pom on the B-turret of Repulse, and that because its crew, as did the Captain Tennant, felt during the last torpedo attack that “This is it” ie felt that Jap VTs had got them cornered and didn’t move fire to other targets when a target plane dropped its torpedo but kept firing at incoming VT until it was torched, only after that took the next nearest VT under fire. So their tactic wasn’t anymore to try to save their ship but to make Japanese to pay max prise for sinking their ship. 

Juha


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## RCAFson (Aug 9, 2010)

> Lets see, the HMS Euryalus manages to demonstrate 10rpm while firing with zero change in elevation,zero change in training and zero change in range when fresh out of harbor and in calm seas in view of shore.
> What happened to the 12 rounds per minute?
> What happens when the turret is moving in train, the guns are changing elevation, the fuse settings keep changing and the deck is rolling and pitching? rate of fire speeds up



HA guns are actually hardest to load at low elevation, as per the example stated. The RN states 10-12 r/m in the gunnery pocket book, and 10 r/m is within that range. 




> the round did not weigh 80lbs, the projectile weighed 80lbs. + the 41lbs of charge and cartridge case.
> the 4.5 weighed 55lbs plus 38.5lbs of charge and cartridge case. the early mountings used a fixed round that combined both weights together. By the way the early twin mounts in the big ships did not have ammunition hoists that came into the mounts. the ammunition hoists/conveyors were outside the mounts and crew men took the rounds from the hoists/conveyors and placed them in two scuttles on the rear of the mount. distance the rounds had to moved from the hoist to the scuttles changed as the mount rotated.
> the 4" used only a fixed round that weighed 63.5lbs.



The 4.5in BD mount fired a 93lb fixed round then, and was able to do so at 12r/m for long periods of time, and it used the same fuse setter and loading tray as the 5.25. The RN/RCN 4" didn't even have a loading tray and the entire round had to be pushed up into the breech with one hand, yet they could still fuse and load it at better than 15 r/m. I think we will have to agree to disagree regarding the 5.25 ROF as I think the evidence is pretty strong that it could fire at 10 r/m in combat.





> Except you made a few mistakes and/or fudged a few things.
> 
> you left out the South Dakotas 20 5in guns or only counted them as 8 guns?
> Hornet CV 8the one at Santa Cruz had eight 5 in guns.
> ...



South Dakota had 16 x 5" and was the only new USN battleship with 16 5" guns. I actually added it up correctly as I made a subtotal for each class of ship and I used the correct numbers in the subtotal.


> Both US cruisers had had their 5"/25s (not really dual purpose but dedicated AA guns) doubled to 8 per ship after being built but pre war.
> 16 guns instead of 8.
> so US total for heavy cruisers is 24, same as the British.



I'll take your word for that as I can't find specifics on two of those ships.



> As for the 76 DP guns on the British destroyers, I think you are being more than a bit optimistic.
> The twin 4.7 had the elevation problem of 40 degrees, why don't you get out your pencil and paper and protractor or better yet some trig tables.
> of from the Wiki page on the 5.25" gun.
> " Hodges, Tribal Class Destroyers, p32: Diagram of High Level Bomber Attack: A 240mph target, at 12 thousand feet altitude could expect to be under for fire about 75 seconds, from the time it enters the effective range of the HACS until it flies to within the minimum range of a 5.25 gun elevated to 70 degrees. A Tribal class destroyer would be able to engage the same target for about 37 seconds."
> Please note that the minimum range for the 4.7 would be at a much longer distance than the 5.25". In fact (if I have done the math right) the 240mph target at 12,000ft would be safe from a 4.7in armed destroyer once it got within 4768yds of it.



If the IJN focused their attacks on USN destroyers at Coral Sea, Midway and Santa Cruz, I would agree that 40deg elevation was a serious handicap, but they didn't, did they? The RN chose 40deg elevation because it still allowed the destroyers to provide AA coverage to capital ships within the destroyer screen, which was typically about 5-6000 yards from the screening destroyers.* Your example actually proves that 40deg elevation DP guns can provide effective AA defense for capital ships, just as the RN worked out pre-war. 
*


> The J class (and follow ups) had inferior AA fire control to the Tribals for the 4.7s.
> As for the 4in gun that replace the bank of torpedo tubes, it wasn't connected to anything. It depended on the gun captain's squinty eye for range, speed , altitude and course. It also depended on his wetted finger held up for atmospheric conditions data (doesn't work to well on a moving destroyer). And depended on the aimer and trainers cartwheel sights for final aiming.



As per wikipedia, the J-k-n class had their AA FC upgraded to match the Tribal class. The 4in gun could still receive AA direction from then main FC via phones and could still provide a long range barrage, and close range defence by eye sights, but I agree that another quad pom-pom would be better.




> The 4.7s on the Os and Ps (those that had them) were hand worked and not power worked.
> The were fitted with 4 single 20m as completed and were later changed (in most) to 2 singles and 2 twins for 6 barrels.
> The Q and R classes did get the better "tribal" AA director set up but the guns were essentially unchanged from the H class if not earlier.



If you are firing at long range aircraft, even hand worked guns can keep up. Doubtless their are minor variations in the close range fit, but it doesn't make much difference.



> Of course if your really want to disagree with my assessment of the 4.7" guns as dual purpose you could always claim that the the 8" guns on the British cruisers were dual purpose because of their 70 degree elevation, of course they have that fixed loading angle down at 10 degrees that you complain about with the Japanese ships.
> The Japanese also provided AA shells even for battleship guns but that doesn't really make them true AA guns or dual purpose does it?



The RN actually provided a radar ranging system for non AA FC controlled guns called the Auto Barrage Unit:



> _The Auto Barrage Unit or ABU, was a specialized gunnery computer and radar ranging system that used Type 283 radar. It was developed to provide computer prediction and radar anti-aircraft fire control to main and secondary armament guns that did not have inherent anti-aircraft capability. The ABU was designed to allow the guns to be pre-loaded with time fused ammunition, and it then tracked incoming enemy aircraft, aimed the guns continuously to track the aircraft, and then fired the guns automatically when the predicted aircraft position reached the preset fuse range of the previously loaded shells.[32] The ABU was also used with guns that were nominally controlled by the HACS to provide a limited blind fire capability.[33]_


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## renrich (Aug 9, 2010)

Post # 117. Nik I stronly question the tonnage numbers. It shows the US sank in surface battles 33900 tons. The Kirishima was around that tonnage figure and sunk at Guadalcanal. The Furutaka was at least 7500 tons and the IJN DDs at Guadalcanal had substantial losses. I am doing this from memory but that 33900 figure looks fishy to me. Pun intended.


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## Juha (Aug 9, 2010)

Hello RCAFson
Quote:"The 5.25 forced two bombers to abort..."

Thanks for that info, IMHO that was an achievement, not that of damaging lightly x planes. IMHO the badly damaged plane, if it was one of those damaged in this occasion, was an achievement.

Quote:"I don't understand, you are arguing that KM AA wasn't hopeless, yet Tirpitz's 4.1in guns had a slower traverse than the RN 5.25in."

Simply because to me the real results are what counts, so 2 out of 12 and effectively prevent accurate torpedodropping was a good achievement.

Quote:"So agree that RN was ahead in AA capability in Oct 1942?"

No, unless you can show that RN AA did better than what USN AA achieved at Santa Cruz

BTW Repulse had 6 4" AA guns and 3x 8 pom-poms IIRC and might well has been able to use it 9-12 x 4" LA guns against VTs

Juha


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## RCAFson (Aug 9, 2010)

> Something I have never disagreed with. What I have said is that switching from one target to another is critical. A point you have not adressed
> 
> 
> Now I must ask who do I prefer to believe. An article written by an organisation that specialises in this topic, or yourself who has written the article off as being illogical without any evidence. Who would you prefer?



I did address it. But a 10 deg/sec traverse gun can swing 90 degs in the time it takes a 205 knots aircraft to fly about 1000 yds. This is hardly a serious handicap, and again 10degs/sec is better than most Axis AA guns.
*
The RN was an "an organisation that specialises in this topic" and they say 10-12 r/m and I believe them.*




> Because ships get damaged and power can fail in combat.



Fine, can a USN battleship 5" twin turret function without power at a 10-11 degree list? As I asked earlier can any turret function under those conditions?




> I didn't ask if higher is better, I asked WHY would they make the change. After all it would involve slowing production, taking design experts from other areas of development. You don;t do this in a war without a very good reason. The questions stands Why did the RN make the change.
> Of course the Japanese had DP guns no one is saying they didn't and the comment about close range targets didn't exist in 1940 I take to be a joke, you are kidding right?



It was becoming apparent by 1942 that the Luftwaffe would be introducing high speed guided missiles while very high speed fighter bombers were also appearing. These trends were not evident when the 5.25in gun was designed, nor was VT ammo, and a 20deg/sec 5.25 mount with VT ammo would be better able to engage very close range, very high speed targets.


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## Juha (Aug 9, 2010)

Hello RCAFson
on that 40deg, now the plan was during the Pedestal that appr 3 DDs were 2000ys out of the heavy ships, other DDs 4000-6000y out. But when ships manouvered wildy under air attacks the distanced changed and sometimes even the outer DDs were much nearer to heavy ships than 4000y. And the 85 deg elevation of US DDs allowed that USN's anti-aircraft formation was that DDs were around heavy ships 2000y out. AND if you look pictures of RN Pacific Fleet under air attack in 1945 you can see that for some reasons the DDs (Ts and Us) were much nearer than 6000y from carriers. Why, for some reason when 55 deg elevation allowed it, also RN DDs operated much closer to carriers than that 4000-6000y.

Juha


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## Nikademus (Aug 9, 2010)

RCAFson said:


> Thanks for the AA totals but how did you conclude that RN AA was less effective? .



I didn't. My fumble fingers however are known Anglophobs! 

I have corrected the post to what i really meant to say and have sentenced my fingers to holding a cup of Tea for an hour in public.


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## Nikademus (Aug 9, 2010)

renrich said:


> Post # 117. Nik I stronly question the tonnage numbers. It shows the US sank in surface battles 33900 tons. The Kirishima was around that tonnage figure and sunk at Guadalcanal. The Furutaka was at least 7500 tons and the IJN DDs at Guadalcanal had substantial losses. I am doing this from memory but that 33900 figure looks fishy to me. Pun intended.



The figures were for the Med Theater.


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## RCAFson (Aug 9, 2010)

Juha said:


> Hello RCAFson
> Quote:"The 5.25 forced two bombers to abort..."
> 
> Thanks for that info, IMHO that was an achievement, not that of damaging lightly x planes. IMHO the badly damaged plane, if it was one of those damaged in this occasion, was an achievement.
> ...



My point is that Navweaps says that 10/sec traverse is too slow yet Tirpitz was able to use her 4.1in AA effectively. Navweaps opinion on traverse rates is, therefore, wrong.

Most sources state 4 x 4" singles on Repulse. Repulse was fitted with two experimental 4" twin turrets but these were removed prewar and replaced with 4" singles, according to:
World War 2 Cruisers

The RN did better during PQ-18 and Pedestal and did so against heavily armoured Luftwaffe aircraft.


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## RCAFson (Aug 9, 2010)

Juha said:


> Hello RCAFson
> on that 40deg, now the plan was during the Pedestal that appr 3 DDs were 2000ys out of the heavy ships, other DDs 4000-6000y out. But when ships manouvered wildy under air attacks the distanced changed and sometimes even the outer DDs were much nearer to heavy ships than 4000y. And the 85 deg elevation of US DDs allowed that USN's anti-aircraft formation was that DDs were around heavy ships 2000y out. AND if you look pictures of RN Pacific Fleet under air attack in 1945 you can see that for some reasons the DDs (Ts and Us) were much nearer than 6000y from carriers. Why, for some reason when 55 deg elevation allowed it, also RN DDs operated much closer to carriers than that 4000-6000y.
> 
> Juha



Destroyers had to stay outside the self destruct range of 40mm ammo. A destroyer might position itself behind or in front of a carrier to provide a close range barrage.


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## Juha (Aug 9, 2010)

Hello RCAFson
if you read carefully WW2 Cruisers, they gave the right info, 6 4” HA guns for Repulse, and she had 2 HACS.

Quote:” My point is that Navweaps says that 10/sec traverse is too slow yet Tirpitz was able to use her 4.1in AA effectively. Navweaps opinion on traverse rates is, therefore, wrong.”

Based on what? I don’t know which type of guns shot down those 2 Albacores, 20mm, 37mm or 105mm (4.1”) or even 150mm, do you? And after all slow training didn’t made it impossible to shoot down a/c it just made it more difficult.

Quote:” The RN did better during PQ-18 and Pedestal and did so against heavily armoured Luftwaffe aircraft”

Have you info on the real LW losses during PQ-18 attack? I have and on no day they were not as bad as was IJNAF’s at Santa Cruz.The total number of a/c lost to all causes (incl. those shot down by FAA fighters) during the whole several days attack period (from 13 to 18 Sept 42) was not much more than that USN AA shot down in one day, LW losses during the attacks on PQ 18 were some 28-31 planes. And if we counted also those shot down by F4Fs at Santa Cruz, well.

And can you give me info what heavy armour there was in the nose of He 111. Now He 111 could take more damage than Kate, but not because it was armoured, the armour protected it from fire from behind, but being twin engine plane with good bullet proof fuel tanks. But it was also bigger plane with stricter torpedo dropping parameters. So maybe somewhat more difficult target to AA but not significantly, but for pilot there was only Plexiglas between him and the target. 

Juha


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## Glider (Aug 9, 2010)

RCAFson said:


> I did address it. But a 10 deg/sec traverse gun can swing 90 degs in the time it takes a 205 knots aircraft to fly about 1000 yds. This is hardly a serious handicap, and again 10degs/sec is better than most Axis AA guns.
> *
> The RN was an "an organisation that specialises in this topic" and they say 10-12 r/m and I believe them.*


When I was in the RN I was told that the 3in 120 rpm and it did in trials but 90rpm as the max in real life so I have a certain caution about things like this. Caution based on real life and personal experience. So when I am told that the 5.25 couldn't do the designed 12rpm because of practical problems in real life I believe them.
A clue was in the demonstration detailed when they managed 10rpm in an ideal situation. You never did explain why they didn't manage the 12rpm.


> It was becoming apparent by 1942 that the Luftwaffe would be introducing high speed guided missiles while very high speed fighter bombers were also appearing. These trends were not evident when the 5.25in gun was designed, nor was VT ammo, and a 20deg/sec 5.25 mount with VT ammo would be better able to engage very close range, very high speed targets.


So the British wanted to improve the training speed of their AA guns because of guided missiles in 1942, a new idea that I will grant you. You can of course support this statement


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## RCAFson (Aug 9, 2010)

Glider said:


> When I was in the RN I was told that the 3in 120 rpm and it did in trials but 90rpm as the max in real life so I have a certain caution about things like this. Caution based on real life and personal experience. So when I am told that the 5.25 couldn't do the designed 12rpm because of practical problems in real life I believe them.
> A clue was in the demonstration detailed when they managed 10rpm in an ideal situation. You never did explain why they didn't manage the 12rpm.
> So the British wanted to improve the training speed of their AA guns because of guided missiles in 1942, a new idea that I will grant you. You can of course support this statement



I fully agree that one should be skeptical, but in this case we have an RN gunner confirming the stated ROF. I don't undestand why you are fixated on 12 r/m when the reference states 10-12 r/m. 

As I explained, this was not an "ideal situation" as the loading tray is at it's most difficult loading angle when the gun was being loaded at low angles of elevation. You can see in this film clip at 3:39 how the 4" twin mount actually has to be elevated to be loaded at low angles:
NARVIK MATERIAL - British Pathe

So you are claiming that the aerial threat didn't evolve during WW2? That is also a "new idea" that I am sure you can support with abundant references?


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## RCAFson (Aug 9, 2010)

Juha said:


> Hello RCAFson
> if you read carefully WW2 Cruisers, they gave the right info, 6 4” HA guns for Repulse, and she had 2 HACS.
> 
> Quote:” My point is that Navweaps says that 10/sec traverse is too slow yet Tirpitz was able to use her 4.1in AA effectively. Navweaps opinion on traverse rates is, therefore, wrong.”
> ...



I am sorry but I read the info on WW2 Cruisers again and it states that Repulse had her two twin 4" experimental turrets replaced by 2 single 4" before the war began, leaving her with 4 4" HA guns.

Maybe you could provide your figures for PQ-18? The other thing to remember is that attacks on a convoy do not have a central focus, and so the AA coverage has to be spread wider and the enemy can make multiple attacks on multiple targets at the same time. Against a carrier task force, the carrier becomes the central focus of the attack and the defence can concentrate accordingly.

Look, it is painfully obvious that even 8/degs second of training is quite sufficient for most WW2 aerial targets. I have a feeling that if navweaps said the world is flat, that I would have to prove otherwise...

AA fire involves time fuzed shells bursting around the target, with close range weapon also enaging from in front, below and behind, and armour and self sealing tanks will help reduce losses, or are you now going to argue that armour and self sealing tanks were a waste of time?


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## Glider (Aug 9, 2010)

RCAFson said:


> I fully agree that one should be skeptical, but in this case we have an RN gunner confirming the stated ROF. I don't undestand why you are fixated on 12 r/m when the reference states 10-12 r/m.
> 
> As I explained, this was not an "ideal situation" as the loading tray is at it's most difficult loading angle when the gun was being loaded at low angles of elevation. You can see in this film clip at 3:39 how the 4" twin mount actually has to be elevated to be loaded at low angles:
> NARVIK MATERIAL - British Pathe
> ...



Because in the real world the 5.25 was seen as a dissappointment in the AA role. Why when you are being questioned about the 5.25 do you present a clip of the 4in totally different in every way as a type of support?
Of course the threat developed, mainly in the numbers used, not individual speed, but the idea that the RN developed their weapons because of guided missiles in 1942 is a joke that does you no credit and only make you look foolish. You cannot possibly support that statement.


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## Juha (Aug 9, 2010)

Hello RCAFson
maybe a third try, 2 LA 4” and 2 3” HA replaced by 4 4” HA, then 2 twin BD turrets put in but removed later (in fact because PoW went to an official visit to Canada and needed suitable suits and a pool and not put back when Repulse returned in UK) and replaced by 2 single 4” HA. You can see the HA guns in photos, first pair was on main deck just front of the boats, second pair abreast the second funnel high up and those which replaced the BD turrets abreast the main mast on one deck above the main deck.

I gave the figures, I don’t bother be more precise because most of planes are said “went missing near Spitsbergen, went missing after forced landing into sea etc”, on some mentioned “shot down by the AA of PQ-18”, on few “shot down by a fighter”, I also incl those which crashed on landing while returning from combat mission, if damage was 60% or more.

As I wrote bullet proof fuel tanks increased survivability but armour, which increased significantly survivability against attacks by .303 mgs armed Sea Hurricanes, there was a heated after action debate on this because amongst the cargo of the merchantmen of PQ-18 there were cannon armed Hurricanes, hasn’t so much effect because most of the AA became from frontal sector and from airburst most of the splinters go forward

Juha


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## RCAFson (Aug 9, 2010)

Glider said:


> Because in the real world the 5.25 was seen as a dissappointment in the AA role. Why when you are being questioned about the 5.25 do you present a clip of the 4in totally different in every way as a type of support?
> Of course the threat developed, mainly in the numbers used, not individual speed, but the idea that the RN developed their weapons because of guided missiles in 1942 is a joke that does you no credit and only make you look foolish. You cannot possibly support that statement.



I read through the despatches here:

Loss of Force Z:
http://www.ibiblio.org/hyperwar/UN/UK/LondonGazette/38214.pdf

Battle of Crete:
http://www.ibiblio.org/hyperwar/UN/UK/LondonGazette/38296.pdf

Mediterranean convoys:
http://www.ibiblio.org/hyperwar/UN/UK/LondonGazette/38377.pdf

and I can't find any criticism of the 5.25 gun. 

I showed you an example of how the height of the breech makes a HA gun more difficult to load at low elevations. The breech in the 5.25 is at maximum height at close range, and the loader will have to lift the 80lb round higher than when engaging HA targets.

The RN continued to develop new weapons and improve older ones to meet an evolving threat. The USN began guided missile development pre-war and work on the Bat GM in Jan 1941:
Bat (guided bomb) - Wikipedia, the free encyclopedia
Howeth: Chapter XL (1963)
and the RN would have apprised of these developments and the need to defend against them. The development of VT ammo gave guns the ability to defend against these weapons even at very close ranges, where target bearing would increase rapidly, and of course the UK had an active jet aircraft research program.

Warship 2007, p11. The RN was working on guided projectiles prewar (of course it was obvious even then that Queen Bee could be used as a weapon) and the UK was working on beam riding weapons during the war.

So the idea that guns would need to deal with high speed robot "kamikaze" weapons was hardly new. The Allied intelligence services kept close track of Nazi missile development, and the RAF even launched a massive raid on an island called Peenemünde...maybe you've heard of it?
Bombing of Peenemünde in World War II - Wikipedia, the free encyclopedia

However, we are certainly getting off topic here. I think I've built a pretty good case for the RN being ahead of the USN in AA in Oct 1942, but of course by Jan the USN was introducing the VT round and mass producing the 40mm gun, so by early 1943 the USN must have overtaken the RN.


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## RCAFson (Aug 9, 2010)

Juha said:


> Hello RCAFson
> maybe a third try, 2 LA 4” and 2 3” HA replaced by 4 4” HA, then 2 twin BD turrets put in but removed later (in fact because PoW went to an official visit to Canada and needed suitable suits and a pool and not put back when Repulse returned in UK) and replaced by 2 single 4” HA. You can see the HA guns in photos, first pair was on main deck just front of the boats, second pair abreast the second funnel high up and those which replaced the BD turrets abreast the main mast on one deck above the main deck.
> 
> I gave the figures, I don’t bother be more precise because most of planes are said “went missing near Spitsbergen, went missing after forced landing into sea etc”, on some mentioned “shot down by the AA of PQ-18”, on few “shot down by a fighter”, I also incl those which crashed on landing while returning from combat mission, if damage was 60% or more.
> ...



OK, I think you are correct about 6 4in HA guns on Repulse. I found a line drawing of her in 1940 and it does show 3 4in HA guns per side:
http://www.kbismarck.com/repulse40.gif

IIRC, the Hurricane pilots did not make many claims during the PQ-18 operation, so that leaves most of the kills to the AA guns.


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## Freebird (Aug 10, 2010)

Glider said:


> I think its worth mentioning that the HACS worked to some degree over Force Z despite the problems. If I remember correctly a high proportion of the high level bombers were damaged and had to abandon the original plan for them to attack twice.
> Could be wrong on this but its something that I recall



The account i have says that all of the Nell bombers were hit by HA AAA in the first attack, but still released bombs. However neither Repulse or PoW had any critical bomb damage.



RCAFson said:


> This discussion is about AA capability.



Strange, for some reason i thoght this thread was about Dive bombers.


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## parsifal (Aug 10, 2010)

My opinion is that we should try and reach some consensus and then move back on topic. 

I think that RN AA was effective, but I would never say it was the best. The RN had its share of problems, but it was still quite useful and effective. It had quite good success against divebombers.

Hopefully we can start to move back closer to the discussion topic


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## Juha (Aug 10, 2010)

Hello RCAFson

Quote:” IIRC, the Hurricane pilots did not make many claims during the PQ-18 operation, so that leaves most of the kills to the AA guns.”

Yes, only 3 Ju 88A-4s from 8. and 9./KG 26 definitely shot down by fighters on 14 Sept. Few more of the missing a/c might well have been succumbed to fighter attacks but definitely the AA was the major killer.

On HMS Repulse, just for the record, I mixed two things, Repulse transported the PoW to South Africa and South America in 1925. But the twin 4” BD turrets were removed because of the planned trip of King and Queen to Canada in 1939.

Juha


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## Nikademus (Aug 10, 2010)

parsifal said:


> My opinion is that we should try and reach some consensus and then move back on topic.
> 
> I think that RN AA was effective, but I would never say it was the best. The RN had its share of problems, but it was still quite useful and effective. It had quite good success against divebombers.
> 
> Hopefully we can start to move back closer to the discussion topic




I would second that. Comparing the losses for Santa Cruz and PQ-18 in particular is a slippery slope. Conditions were very different. All and all the RN escort (largely DD's) managed a good fight, dealing very heavy losses to the Luftwaffe crews against a swarming attack on a large convoy of 40 merchants.


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## Shortround6 (Aug 10, 2010)

RCAFson said:


> I think I've built a pretty good case for the RN being ahead of the USN in AA in Oct 1942, but of course by Jan the USN was introducing the VT round and mass producing the 40mm gun, so by early 1943 the USN must have overtaken the RN.




No, you haven't.
You have built a good case that the RN had more 40mm pom-pom barrels mounted than the US had 1.1in barrels mounted and you have shown that the RN may have had more even lighter AA mounted.
You have not shown that RN was actually ahead of of the US in larger DP guns, either in barrels mounted or capability of those barrels.
You have not shown that the RN was ahead in fire control, that is that their directors PERFORMED better than the US directors. 
Radar is a sensor, it can feed more accurate information to a director than an optical sight/device can but if the director and or system of getting aiming information to the guns is defective or performs poorly the radar alone may not be able to make up the difference. 
Many countries were working on advanced AA mountings for ships and advanced ideas for directors. The problem was turning the ideas into actual working hardware that would work and CONTINUE to work at sea. Another problem was that many of these "ideas" were tried one at a time instead of in combination or were tried too many at a time and so failed to keep working when needed. 
The Germans who you seem to claim were so far behind not only had tri-axial stabilized mountings for their twin 8.8 and 10.5 cm guns but had a tri axial stabilized mounting for their twin 37mm AA guns. They paid a penalty in that the big gun mounts weighed as much as a British low angle twin 12cm mount. THE 37mm was let down by the fact that the guns were not automatic but were miniature big guns. Each round had to be hand loaded. There were also maintenance and reliability issues with both mounts, but the "idea" was advanced. The 37mm mount was also heavy and hand powered. 
The Italians had a quad stabilized 90mm mounting but again it was stretching what was possible too far. And, again, sophistication has a price. Was 19 tons too much to pay for a single 3.5" AA gun no matter how sophisticated the mount? They were also working on RPC. Some Italian destroyers had both a pair of 40mm pom-pom guns and a pair of 13mm MG mounts, not either/or like too many British destroyers. 
The British were certainly aware that the Japanese destroyers had main guns with high elevation, they may not have known the rate of fire or loading angle problems. 

The cost associated with good AA defense was not the cost of the guns themselves, or even in some cases the mounts, but the cost of the increased size of the ship needed to carry the AA armament. For every ton of armament weight you need several tons of ship to support it and for every foot in hight above the water you need either ballast weight or a larger hull to maintain stability. Adding several tons of "improved" AA director on top of the bridge can call for extreme weight savings in other areas or a new hull in future classes. With destroyer tonnage limited by treaty Navy's had to accept limits on capabilities or limits on numbers. 

The RN's .5in MG mount was an overweight piece that provided little firepower for the space and weight it took up. Awkward to use, it might have been a viable weapon in 1930 or so but by 1939 it was of little use. The tonnage may have been better used by free swinging mounts like the US was using on it's .50cals or the Germans were using on their 20mm guns even if they weren't the equal of the later Oerlikon


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## Glider (Aug 10, 2010)

RCAFson said:


> However, we are certainly getting off topic here. I think I've built a pretty good case for the RN being ahead of the USN in AA in Oct 1942, but of course by Jan the USN was introducing the VT round and mass producing the 40mm gun, so by early 1943 the USN must have overtaken the RN.



Interestingly I do agree with this comment. We disagree on the 5.25 but this summary I do go with. However it is to simplistic. My own summary would split the HAA and LAA.

HAA
There is no doubt in my mind that the 5in L38 was the best all round destroyer gun of the war and far more effective than those fitted to British destroyers. That said the RN twin 4in, twin 4.5 were good guns so the difference wasn't that great when Cruisers and Capital ships were taking on aircraft and the 5.25 could be effective depending on conditions.
_note _- I don't include the 4.5 carried on destroyers in this section. They would have been ok against torpedo bombers but nothing at altitude.

However we are talking about September 1942 and without the VT fuze the potential for the 5in L38 was significantly reduced.

LAA
On this in 1942 I believe that the RN had an advantage with the exception of the few USN ships fitted with the 40mm which was just entering service. Almost every british destroyer had a quad 2pd and 6 - 8 20mm, some had more some less but this is a fair summary. Cruisers and heavier ships carried more. 

The problem that the USN had was that they were more or less limited to the 1.1 in one of the most dissapointing weapons used by the USN, the 0.5 mg which lacked firepower and the 20mm which was effective but on the small side. As mentioned earlier those few ships with the 40mm had a clear advantage.
The Bristol class destroyer in production up till 1942 had as their initial war changes the loss of a set of torpedos for 4 x 20mm and then the quad 1.1in removed for another 2 x 20mm. Even the first Fletcher class DD's which entered service in 1942 had a quad 1.1in and 6 x 20mm arguably less effective than the LAA carried on the RN destroyers.


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## renrich (Aug 10, 2010)

SR, very nice post, logical and informative. All the AA and radar that was added to ships in WW2 also required crew to man them and spaces to house the added crew and supplies to feed them. The ships got crowded and top heavy. CA25 of the USN stopped in Hawaii and exchanged two scout planes for two twin mount 40 mms but that does not sound like the trade was weight for weight.


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## RCAFson (Aug 10, 2010)

Shortround6 said:


> No, you haven't.
> You have built a good case that the RN had more 40mm pom-pom barrels mounted than the US had 1.1in barrels mounted and you have shown that the RN may have had more even lighter AA mounted.
> You have not shown that RN was actually ahead of of the US in larger DP guns, either in barrels mounted or capability of those barrels.
> You have not shown that the RN was ahead in fire control, that is that their directors PERFORMED better than the US directors.
> ...



I don't want to continue to drag this this thread OT, but...

RN AA proved that it was effective in the Med and in the Arctic. Even over Dunkirk, the RN claimed 35 kills using their prewar AA fit including the much maligned quad .5" and the RN did not seem to make greatly inflated AA claims, as in some other navies (Off Crete, they claimed 22 and probably got close to that number and during Pedestal they claimed 66 from fighters and guns and got 42). The RN's AA FC was vastly improved by Oct 1942 over what it was in 1940 or early 1941, both in quantity in terms of number of AAA and quality, in terms of FC. The RN still had a lead over the USN in OCT 1942 in numbers of DP guns carried and in AAA, when the calibre is considered, although overall AAA numbers had equalized. The RN had advanced tachymetric directors with radar controlling most pom-pom mountings on cruisers and larger, while the same ships also had AA FC radars with gyro tachymetric directors for their DP guns. USN DP guns had been largely ineffective prior to Santa Cruz and even at Santa Cruz it seems likely that the 20mm guns were the big killers, and the 40mm bofors was still a very scarce item as was the Mk51 gyro director for bofors.

The KM did not provide director control for any AAA mountings, and neither Bismarck's nor Tirpitz had a stellar record against aircraft, with Bismarck being unable to make a single kill. Neither the KM, Italian navy, nor the IJN ever developed AA FC radar or provided their close range weapons with gyro based tachymetric AA directors.

In the Pacific, Force Z matched the USN, in numbers ofAA kills for the USN's first 3 major carrier battles, which featured massed defence by the USN's best ships, while Force Z had to make do with 3 destroyers with no AA FC and an elderly battlecruiser that barely matched a modern RN light cruiser in AA capability, and even Prince of Wales was having major equipment problems. Given equal numbers of equivalent ships it seems likely that the RN could have exceeded the USN's AA kill rate at Santa Cruz because the tachymetric radar controled pom-pom was a more effective weapon than that carried on the USN ships, save for the quad bofors which were still rare. If the quad 1.1" was effective it didn't show it at Eastern Solomons where it was available in quantity on both Enterprise and USS North Carolina which were the focus of the attack. In that action the USN claimed 28 AA kills and got 5 (including an F4F). 

I agree fully with your 2nd to last paragraph and in light of the poor record of USN DP guns on destroyers, the RN decision to forgo a HA DP main armament in favour of 40 deg elevation but with the addition of a quad pom-pom, seems like the the correct decision, although it probably didn't seem so at the time, especially in light of the USN's wild over claiming in 1942.

Regarding the quad .5", I agree that it was ineffective in a relative sense, but simple logic tells me that a Ju-88 or He-111 that strayed too close to a quad .5" mount, would feel some major pain if the mounting even got on target for 1 second. It must also have deterred strafing attacks where the quad .5" would be presented with a low deflection shot, and could stay on the target more easily.


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## Shortround6 (Aug 10, 2010)

Glider said:


> Almost every british destroyer had a quad 2pd and 6 - 8 20mm, some had more some less but this is a fair summary.



There were 85 British destroyers built after 1925 that did not have quad pom-pom guns. 'A' to 'I' classes. 45 of them were sunk or out of action by the end of 1942. Including the Tribals going on to the 'N' class adds another 56 destroyers. Just under 40% had the quad 2pd and the percentage is only that high if you don't count any of the WW I veterans. of the 40 destroyers of the Tribal and 'J', 'K' and L classes 27 of them were sunk or permanently out of action by the end of 1942.
This is from all causes, gunfire, torpedo, mine and air attack. There is no doubt that they ALL were hard worked and did more than their share in gaining victory. There is also little doubt that more of their crews might have returned home if they had had better AA armament. 


Glider said:


> The problem that the USN had was that they were more or less limited to the 1.1 in one of the most dissapointing weapons used by the USN, the 0.5 mg which lacked firepower and the 20mm which was effective but on the small side....... Even the first Fletcher class DD's which entered service in 1942 had a quad 1.1in and 6 x 20mm arguably less effective than the LAA carried on the RN destroyers.



The 1.1 is an interesting story in the best being the enemy of good, complications that sound good but don't work out and good intentions. 
It was specifically designed to be an anti-dive bomber gun (how about that, we are somewhat back on track  and was the smallest caliber that could be made to use a 1lb high explosive projectile and so meet the requirements of the St. Petersburg treaty that banned exploding bullets. Work was started in 1930 when such things were still considered to be important. Rate of fire was slowly improved to the point where they got 140 rpm from one barrel so a quad mount was decided upon to "equal" the rate of fire of a single .50 cal MG. Granted each hit would be much more devastating. In order to deal with dive bombers (of which the US Navy was experimenting with in 1930) the mount was given 110 degrees of elevation to compensate for roll and such when the target is coming STRAIGHT down. Because normal traverse was of little use in such situations it was also arranged so that the barrels could pivot or swing 30 degrees to either side of the dead center position without the entire mount traversing. Naturally such refinements added size and weight to the mount. This being the best being the enemy... In practice the extra traverse was either locked out or eliminated but too late to save weight. The 10 degree elevation might not have been needed in practice either. The 1.1 was a fairly powerful round for it's caliber with more recoil than the mount could stand up to initially and it had to be beefed up. While it did have tracer unlike early British 2pdr ammunition it did not have a self destruct and so didn't make those little puff balls of smoke several thousand yds out to deter attacking aircraft.
In the end it would up being overweight for the firepower it offered, like many other early weapons/mounts in the 20mm to 40mm range.


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## Glider (Aug 10, 2010)

renrich said:


> SR, very nice post, logical and informative. All the AA and radar that was added to ships in WW2 also required crew to man them and spaces to house the added crew and supplies to feed them. The ships got crowded and top heavy. CA25 of the USN stopped in Hawaii and exchanged two scout planes for two twin mount 40 mms but that does not sound like the trade was weight for weight.



I thin its worth remembering that generally the USN ships were top heavy to begin with and any addition needed serious changes.

There has been some discusson about the RN quad 0.5 but by the period we are talking about these had been replace by 20mm guns and shouldn't really be taken into account.


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## Glider (Aug 10, 2010)

Shortround6 said:


> There were 85 British destroyers built after 1925 that did not have quad pom-pom guns. 'A' to 'I' classes. 45 of them were sunk or out of action by the end of 1942. Including the Tribals going on to the 'N' class adds another 56 destroyers. Just under 40% had the quad 2pd and the percentage is only that high if you don't count any of the WW I veterans. of the 40 destroyers of the Tribal and 'J', 'K' and L classes 27 of them were sunk or permanently out of action by the end of 1942.
> This is from all causes, gunfire, torpedo, mine and air attack. There is no doubt that they ALL were hard worked and did more than their share in gaining victory. There is also little doubt that more of their crews might have returned home if they had had better AA armament.


True but slightly off centre. Few of the A to I class and none of the VW WW1 vessels were with the Battleships and aircraft carriers by the end of 1942. Most but not all of those left were concentrated in the Atlantic and a number were converted for escort duty with guns and torpedo's removed, additional depth charges, huff duff fitted and so on. The Fleet destroyers generally were the newer destroyers fitted as mentioned in my previous posting. It should also be remembered that 15 of the O, P and Q classes were launched in 1941 and would have started to come on stream over this period. I don't have completion or commisioning dates for these vessels



> The 1.1 is an interesting story in the best being the enemy of good, complications that sound good but don't work out and good intentions.
> It was specifically designed to be an anti-dive bomber gun (how about that, we are somewhat back on track  and was the smallest caliber that could be made to use a 1lb high explosive projectile and so meet the requirements of the St. Petersburg treaty that banned exploding bullets. Work was started in 1930 when such things were still considered to be important. Rate of fire was slowly improved to the point where they got 140 rpm from one barrel so a quad mount was decided upon to "equal" the rate of fire of a single .50 cal MG. Granted each hit would be much more devastating. In order to deal with dive bombers (of which the US Navy was experimenting with in 1930) the mount was given 110 degrees of elevation to compensate for roll and such when the target is coming STRAIGHT down. Because normal traverse was of little use in such situations it was also arranged so that the barrels could pivot or swing 30 degrees to either side of the dead center position without the entire mount traversing. Naturally such refinements added size and weight to the mount. This being the best being the enemy... In practice the extra traverse was either locked out or eliminated but too late to save weight. The 10 degree elevation might not have been needed in practice either. The 1.1 was a fairly powerful round for it's caliber with more recoil than the mount could stand up to initially and it had to be beefed up. While it did have tracer unlike early British 2pdr ammunition it did not have a self destruct and so didn't make those little puff balls of smoke several thousand yds out to deter attacking aircraft.
> In the end it would up being overweight for the firepower it offered, like many other early weapons/mounts in the 20mm to 40mm range.


It had other problems as well including the large gun crew needed to operate it and reliability. Either way it was removed just as quickly as they could get rid of it.


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## RCAFson (Aug 10, 2010)

Shortround6 said:


> There were 85 British destroyers built after 1925 that did not have quad pom-pom guns. 'A' to 'I' classes. 45 of them were sunk or out of action by the end of 1942. Including the Tribals going on to the 'N' class adds another 56 destroyers. Just under 40% had the quad 2pd and the percentage is only that high if you don't count any of the WW I veterans. of the 40 destroyers of the Tribal and 'J', 'K' and L classes 27 of them were sunk or permanently out of action by the end of 1942.
> This is from all causes, gunfire, torpedo, mine and air attack. There is no doubt that they ALL were hard worked and did more than their share in gaining victory. There is also little doubt that more of their crews might have returned home if they had had better AA armament.



The RN also had 45 or so Hunt class destroyers in service by Dec 1941, which had quad pom-poms and about a dozen or so AA sloops.

OTOH, in Sept 1939 the USN had about 45 modern destroyers with DP guns but also about 100 old "four stackers":



> _As 1940 began, with World War II already under way in Europe, the US Navy had 170 flush-deckers in and out of commission. After fifty were transferred to the Royal Navy later that year, 120 hulls remained; these included 101 in commission, 18 of which were conversions._


 
Additionally about 16of the older RN V and W class destroyers were converted to AA escorts, under the WAIR program by mid 1940, and they were typically rearmed with HA FC, 2 x twin 4in HA and 2 x 1 pom-poms or 2 x quad .5". One of the larger destroyer leaders also received a quad pom-pom:
http://en.wikipedia.org/wiki/V_and_W_class_destroyer#WAIR


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## Shortround6 (Aug 10, 2010)

RCAFson;704452
Regarding the quad .5" said:


> Your simple logic is quite wrong. Unless of course the He-111 managed to overfly the target at almost point blank range.
> The gun layer had a geared elevation drive hand wheel and the gun trainer had a gear drive also which could be de-clutched to allow the mounting to be "pushed around" Since the mounting was well over one ton even the rotating part must have weighed a considerable amount. The "push bars" were also at waist or hip height which probably didn't help anyone trying to 'aim" with them. The hand wheels stayed at a fixed hight/position while the sights traveled in an arc. Aiming at high angles required a lot of neck stretching.
> 
> From "Destroyer Weapons of WW II"
> ...


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## Shortround6 (Aug 10, 2010)

Glider said:


> True but slightly off centre. Few of the A to I class and none of the VW WW1 vessels were with the Battleships and aircraft carriers by the end of 1942. Most but not all of those left were concentrated in the Atlantic and a number were converted for escort duty with guns and torpedo's removed, additional depth charges, huff duff fitted and so on. The Fleet destroyers generally were the newer destroyers fitted as mentioned in my previous posting. It should also be remembered that 15 of the O, P and Q classes were launched in 1941 and would have started to come on stream over this period. I don't have completion or commisioning dates for these vessels



Excuse me, I hadn't realized that we were picking and choosing which month of which year we were comparing. I thought we started talking about difference in AA capability at the beginning of the war. RCAFson then tried to do a comparison for the Battle of Santa Cruz. 

Claiming that the RN had good AA defense near the end of 1942 doesn't do much for all those ships off Norway, Dunkirk, Greece and Crete does it?


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## RCAFson (Aug 11, 2010)

Shortround6 said:


> From "Destroyer Weapons of WW II"
> " Its barrels were deliberately misaligned from each other to give a 'scatter' effect. and later mathematical calculations showed that when firing an approximate ten-second burst at 1000yds range, and assuming the total target was within the pattern of the spread for the duration of the burst, 40 rounds of the 500 fired might hit the target. This sounded hopeful, but took no account of the fact that keeping the target within the pattern depended on the both the Layer and Trainer, independently yet concurrently, exactly judging the speed of the aircraft as well as constantly tracking it by hand-follow on a rolling and pitching deck for ten seconds."
> 
> It rather depends on range as to wither 1, 2, 3, or all four barrels are actually pointed at one aircraft at the same time. While both US and British 1/2in MGs are pop guns compared to some larger AA weapons the British round had about 60% of the muzzle energy of the American round and the difference only got worse with range. The higher velocity of the US .50 also means a slightly shorter time of flight to a given range, I don't know if the difference is of more than academic interest at the ranges these guns would be effective.



1000 yards would be very long range for a 20mm, much less a .5" MG and at 100 yards, the same gun might expect 400 rounds to hit the target, and that would hurt! If all aircraft stayed at 1000 yds, the quad .5" could be considered a success on that point alone. However, such was not always the case:

http://www.royal-naval-reserve.co.uk/images/admiralty/rep3.JPG
http://www.royal-naval-reserve.co.uk/images/admiralty/rep4.JPG
http://www.royal-naval-reserve.co.uk/images/admiralty/rep5.JPG
TM Convoy Report 29 March 1940 (confirmed kill, aircrew identified)
as the above report shows, a .5" MG *and a Lewis gun* downed a JU88. 



Shortround6 said:


> As for the 5.25in dispute I would note a couple of things.
> 1. The "Gunnery Pocket book" seems to a hand book for recruits to give them the basics of their jobs. Not a Critique of British weaponry. Don't want to discourage the men too soon.
> 2. Having said that please look at the diagram of the 5.25 turret in the book. Please notice the separate shell hoists for for L.A. (anti-ship) shells and H.A. (anti aircraft) shells. Notice that the L.A. shell hoists are much nearer to the breech than the H.A. shell hoists and would need less man handling of the shells to load the guns. The L.A. shells also don't to pause at the fuse setter before being loaded. It might be possible to get 10-12 rounds per minute from the 5.25 in a surface action.
> 3. considering that the 4.7in AA guns in the Nelson and Rodney were found to have ammo that was too heavy for sustained fire at 74lb per complete round it is a little difficult to believ that the 80 lb shells for the 5.25 were no problem,. Maybe the WW II sailors were in better shape and better fed than the 1920s and 1930s sailors?



The HA hoist, according to Campbell, actually positions the AA shells directly into the fuze setter, unlike most RN DP guns where the shell has to be placed into the fuse setter manually, such as the *93lb fixed rounds* on the 4.5" twin BD mount. In Jan 1941 HMS *Illustrious reported that her 4.5" guns fired 3000 93lb rounds at an average 12 r/m*. and these were definitely fired at aircraft. The 5.25 loader than has about 5 seconds to transfer the fuzed shell into the loading tray, to maintain 10 r/m. In the mid 1930s the RN actually achieved 15 r/m with the 74lb 4.7" rounds while firing at aircraft:
http://www.admirals.org.uk/records/adm/adm186/adm186-339.pdf (page 142)


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## RCAFson (Aug 11, 2010)

Shortround6 said:


> Excuse me, I hadn't realized that we were picking and choosing which month of which year we were comparing. I thought we started talking about difference in AA capability at the beginning of the war. RCAFson then tried to do a comparison for the Battle of Santa Cruz.
> 
> Claiming that the RN had good AA defense near the end of 1942 doesn't do much for all those ships off Norway, Dunkirk, Greece and Crete does it?



My point is that RN AA was still in 1939, 1940, 1941 and up to and including Oct 1942, better than the USN and every other navy to that point in the war. The USN found out the hard way that 5" DP guns are no substitute for a good LAA outfit, and the paucity of USN AA kills prior to Santa Cruz bears this out. The RN took it on the chin early in the war, but the USN would have been even harder hit had it faced the same attacks.


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## Glider (Aug 11, 2010)

Shortround6 said:


> Excuse me, I hadn't realized that we were picking and choosing which month of which year we were comparing. I thought we started talking about difference in AA capability at the beginning of the war. RCAFson then tried to do a comparison for the Battle of Santa Cruz.
> 
> Claiming that the RN had good AA defense near the end of 1942 doesn't do much for all those ships off Norway, Dunkirk, Greece and Crete does it?



My mistake. Before I reply can I ask what you mean by start of the war i.e UK start or US start?


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## Juha (Aug 11, 2010)

Hello RCAFson
Quote:” My point is that RN AA was still in 1939, 1940, 1941 and up to and including Oct 1942, better than the USN”

Based on what? PQ-18 or Pedestal IMHO didn’t show any clear advance. If Axis lost 42 a/c out of 330 attacking Pedestal, remember that not only RN and FAA made claims but also RAF made at least 14 claims during Pedestal. Was that after all better than USN AA alone shooting down 25 (14 x D3A and 11 x B5N) and USN CAPs 29, ie altogether 54 out of smaller number of attackers. Conditions were different for sure but not all was easier to USN, especially during the Junyo’s main dive-bomber attack conditions were very difficult for AA, Vals popping out of clouds which had base at 300-450m, some even at 150m and warnings, up from Admiral coming in “Don’t shoot own planes, bogies coming in but there are also own planes around”. And in the end of the day IJN lost almost half of its planes participating the battle.

Have you some hard facts, especially against dive bombers to back up your claim? Nobody have argued that the 40deg max elevation of 4.7” guns on DDs was hindrance against Axis torpedo-bombers but that it was a handicap against 

June 42 AA of Yorktown and its screen shot down 2-3 dive-bombers out of 7-8 attacking.

12 Aug 42 RN and FAA shot down 1-2 (Smith in his Stuka book says one by AA and Shores in his Malta: The Spitfire Year says two by fighters but add that fighters claimed 3, of which one was confirmed by the witnesses on both Victorious and Indomitable and HMS Kenya and HMS Charybdis jointly claimed one) out of 12 Stukas from I./StG 3 which knocked out Indomitable with 2 hits and 3 near misses. Now Stukas succeeded to surprise British and first of them had already initiated their dives when British saw them. And the AA cruiser behind the carrier, Phoebe was just engaging Italian torpedobombers with its 5.25”. So at most 1 for AA. Of course Ju 87D-1 was better protected than Val.

26 Oct 42 Enterprise and her screen shot down 3 out of 8 Vals from Junyo attacking her. Vals suddenly popped out of low clouds but on the other hand those clouds forced them to attack at 45 deg dives, which made them easier targets to AA.

RN AA was clearly better than that of IJN, on KM more difficult to say, there was a clear political reason for Bismarck’s record but Tirpitz and its screen didn’t do so badly on 9 March 1942.And IMHO in Oct 42 USN AA might well be better than that of RN.

Juha


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## Juha (Aug 11, 2010)

Hello
checked the Official Histories; RN Official History, Roskill’s The War at Sea, Vol. II [first publ. 1956] p. 305 says that “it appear that they [FAA fighters] and the ships’ guns between them destroyed about thirty of all types during the entire operation [Pedestal].”
Interservice official history, Playfair et al The Mediterranean and Middle East Vol. III [first publ. 1960] p.321 says that the enemy lost 35, including those shot down over Malta. IMHO the Med history is probably most reliable, writers, high ranking Army, Naval and AF officers had access to Ultra messages, but lets say that FAA and ships’ AA got 30 a/c during the Pedestal, FAA claims were 39 IIRC.


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## Nikademus (Aug 11, 2010)

per Bergstrom, Luftwaffe losses during PQ-18 were:

KG-26 - 19 bombers (HE-111/Ju-88 ) 
Kustenfliegergruppen 406/506/906 - 5 x HE-115 

4 possible 109 losses (JG-5)


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## Juha (Aug 11, 2010)

Hello Nikademus
on bombers, I counted also 3 Ju 88A-4s from KG 30, one written off after undercarriage failure during landing, maybe mechanical failure or after effect of battle damage, one missing at Spitsberger and one missing at a square, exact place of which I have not bothered to check. On KG 26 losses there are also few cases in which I have given the benefit of doubt to RN. 
I can find only 3 Bf 109 losses between 13 and 18 Sept, none had anything to do with PQ-18 and one on 19 Sept, shot down in air combat over Murmansk, so most probably by Soviets.

Juha


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## parsifal (Aug 11, 2010)

Juha said:


> Hello RCAFson
> 
> RN AA was clearly better than that of IJN, on KM more difficult to say, there was a clear political reason for Bismarck’s record but Tirpitz and its screen didn’t do so badly on 9 March 1942.And IMHO in Oct 42 USN AA might well be better than that of RN.
> 
> Juha



hi Juha

Glad you raised this. Someone earlier claimed the Italians and the Germans lacked directors for their AA. Not true. According to Campbell both nations had fire control for their HAA. 



In the case of italian FRC, Campbell simply says"Aa FC progressed gradually from barrage to Director control, but the electromechanical computer was too slowfor accurate AA. Gyroscopic and similar directors for close range gunfire was lacking. 

Data transmission from the rangefinders to the gunlaying computers was not entriely satisfactory. Campbell does not say why.

In the case of the Germans had possessed fire control since 1931, beginning with the biaxial Type 1931 and was fitted to the Pocket battleships and the Light Cruisers. The Type 1933 was fitted to the heavy cruisers and the battlecruisers. The type 1937, the best of the prewar directors was fitted to the bismarcks and the Eugen These were all biaxial gyroscopically based directors, and gave good levels of accuracy for non radar directed fire. There were later, radar directed Fc systems for the capital ships, but as a generalization they were not used at sea to any great extent

Some Destroyers began to receive Type 1943 combined HA'LA directors from 1943, and were designed specifically to control the new 128 cm DP guns being developed by Germany at that time.

I have another book on the German Capital ships, which says that the Bismarck was unsuccessful in AA due to faulty settings in the Directors. The germans had not anticipated the very slow speed of the Swordfish, and this meant that most rounds exploded in front of the attacking Swordfish. This was rectified by 1942, along with the fact that the RN was beginning to use faster, more modern attack aircraft. The tirpitz did quite well in the attacks launched against her, both in 1942 and '44.


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## Juha (Aug 11, 2010)

Hello Parsifal
what more in Bismarcks case, its two rear AA directors were older types, without hemispherical armoured cover because German-Soviet Treaty gave to Soviet experts right to examine the rear AA directors of Bismarck, the two AA directors on the sides of Bismarck’s bridge structure were newer ones, out-of-limits to Soviets. And as we know the fatal torpedohit on her was made by a Swordfish which aproached from behind 

Juha


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## RCAFson (Aug 11, 2010)

Juha said:


> Hello Nikademus
> on bombers, I counted also 3 Ju 88A-4s from KG 30, one written off after undercarriage failure during landing, maybe mechanical failure or after effect of battle damage, one missing at Spitsberger and one missing at a square, exact place of which I have not bothered to check. On KG 26 losses there are also few cases in which I have given the benefit of doubt to RN.
> I can find only 3 Bf 109 losses between 13 and 18 Sept, none had anything to do with PQ-18 and one on 19 Sept, shot down in air combat over Murmansk, so most probably by Soviets.
> 
> Juha



Thanks to the power of Google, I found the following website:

Nordic Aviation During WW2

and from the loss registers on the above site, it seems likely that these aircraft were lost while attacking PQ-18 from 12-09-42 - 14-09-42
floatplane:5 x He-115 
Recon: 1x ju:88
Bombers: possible 1 to 4
KG26: 25-26 JU88/He111
KG:30 2 to 4 possible

The website cautions that the records on it are still incomplete, but 40 kills by PQ-18, mostly ( 35+) from AA seem likely.


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## RCAFson (Aug 11, 2010)

parsifal said:


> hi Juha
> 
> Glad you raised this. Someone earlier claimed the Italians and the Germans lacked directors for their AA. Not true. According to Campbell both nations had fire control for their HAA.
> 
> ...



I stated that no KM or Italian destroyer had AA FC for their main guns, which is true, AFAIK. The KM. IJN and Italians also did not introduce tachymetric gyro directors for their LAA. I doubt that any Type 1943 directors actually went to sea. Campbell also states that the KM HA directors were flawed and their stabilization gyros were very prone to damage, and took 20min to start up.


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## RCAFson (Aug 11, 2010)

Juha said:


> Hello
> checked the Official Histories; RN Official History, Roskill’s The War at Sea, Vol. II [first publ. 1956] p. 305 says that “it appear that they [FAA fighters] and the ships’ guns between them destroyed about thirty of all types during the entire operation [Pedestal].”
> Interservice official history, Playfair et al The Mediterranean and Middle East Vol. III [first publ. 1960] p.321 says that the enemy lost 35, including those shot down over Malta. IMHO the Med history is probably most reliable, writers, high ranking Army, Naval and AF officers had access to Ultra messages, but lets say that FAA and ships’ AA got 30 a/c during the Pedestal, FAA claims were 39 IIRC.



Operation Pedestal - Wikipedia, the free encyclopedia :
Royal Navy gunners and Fleet Air Arm fighters shot down 42 of the approximately 330 attacking Axis aircraft.[26]
(26) Naval Staff History, The Royal Navy and the Mediterranean Convoys, p89.


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## Juha (Aug 11, 2010)

Hello RCAFson
If you read the table more carefully you will notice that Ju 88 from Wettererkundungsstaffel 5 wasn't lost, only damaged unknown amount. And the only other recon Ju 88 lost during PQ-18 oper was lost in accident.

On Pedestal sources, staff study is from 1957, so older than official Med history

Juha


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## RCAFson (Aug 11, 2010)

Juha said:


> Hello RCAFson
> 
> Have you some hard facts, especially against dive bombers to back up your claim? Nobody have argued that the 40deg max elevation of 4.7” guns on DDs was hindrance against Axis torpedo-bombers but that it was a handicap against
> 
> ...



Everyone keeps saying how the 5"/38 is such a great gun, but where are the kills to prove it? The experience of the USN was that DP weapons could not protect the fleet, and that the real threat to aircraft was automatic AA, and the RN had heavier batteries of AAA controlled by better methods of FC, in Oct 1942 than the USN - this is what it all comes down to. Here's what Enterprise's gunnery report states, after Santa Cruz:



> _It is believed that the 5-inch guns of screening vessels might best be employed in shooting at enemy planes that have not yet pushed over into their dives. Their problem in this respect is identical to our own.* The fire of 5-inch at diving planes other than a barrage fired by the ship being attacked is ineffective*, but it should be possible to hit them before they start their dives. All supporting ships should direct their 5-inch fire accordingly.
> 
> The 5-inch guns should be equipped with a single man control, either a Mark 51 director or a joy stick similar to that of the 40mm for use against dive bombers. The 5-inch gun can hit, but it is most difficult to get the pointer and the trainer on the same plane. This is important and must be done if we are to stop dive bombers before they release their bombs._


Action Report: 26 October 1942

The USN would have been better off by staying with LA 5" guns and devoting the weight saved to more AAA and the gunnery report from Yorktown at Midway states exactly that:



> B. Gunnery
> 
> 1. The following listed alterations should be installed.
> 
> ...


http://www.ibiblio.org/hyperwar/USN/ships/logs/CV/cv5-Midway.html
So, HA DP guns are only effective at ranges where they really don't need to be "High Angle", as on screening destroyers, just like the RN thought pre-war! Of course, once VT ammo came into use this changed dramatically.


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## RCAFson (Aug 11, 2010)

Juha said:


> Hello RCAFson
> If you read the table more carefully you will notice that Ju 88 from Wettererkundungsstaffel 5 wasn't lost, only damaged unknown amount. And the only other recon Ju 88 lost during PQ-18 oper was lost in accident.
> 
> On Pedestal sources, staff study is from 1957, so older than official Med history
> ...



Unknown damage could equal 99%...there is a good chance that the aircraft could be classed as a kill

I believe that the staff study was classified and was based upon classified info, that could not be released in a public history:



> This book contains the Naval Staff History originally issued by the Admiralty in 1957 as a confidential book for use within the Royal Navy. It has since been declassified and is published here for the first time, along with an extended preface.


The Royal Navy and the Mediterranean Convoys: A Naval Staff History (Hardback) - Routledge


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## Juha (Aug 11, 2010)

Hello RCAFson
we all know, and have knew a while that you think that RN AA was best of the world in early part of the war, but show by some concrete figures when it did clearly better than USN AA.

Again the end of your message #218, do you read the chapter 9 of the action report of Enterprise, USN saw the dive-bombers when they were well in their dives, see my Indomitable case on 12 Aug. 42, RN AA succeeded to shoot down max one out of 12 Dive-bombers in similar circumstances. How that shows that RN automatic AA was better than that of USN?

Weather was rather cloudy during the Japanese attack, which made it difficult especially to heavy AA. 

You quoted Yorktowns combat report but the Enterprise action report, even if critical to the performance of 5" guns gives entirely different recommendations.

On those screenings, as I wrote earlier, USN liked to have its DDs in circular formation 2000y out of the escorted ships, and by the way, according to p. 282 in RN official history, when air attack threatened PQ-18, 8 of the screening DDs moved nearer to the merchantmen, nearer than 1000 y from nearest merchantman, others keep their position 3500-5000y out from the nearest merchantman, so much your 6000 minimum distance for RN DDs.

And your last message clearly shows, that you really see what you want. Maybe some basic study on LW loss reporting might help. notice that the %? was in dam column not in loss column.

And maybe you should find out a bit more on staff studies and why they were classified.


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## Glider (Aug 11, 2010)

There is no doubt that the RN were impressed with the 5in L38. HMS Delhi was fitted out with these in the USA durng a refit in 1941, and the RN tried to aquire 60 gun/director sets for installation in RN vessels. Unfortunately the US were working flat out to fit out their own fleet and none could be spared.


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## RCAFson (Aug 11, 2010)

Glider said:


> There is no doubt that the RN were impressed with the 5in L38. HMS Delhi was fitted out with these in the USA durng a refit in 1941, and the RN tried to aquire 60 gun/director sets for installation in RN vessels. Unfortunately the US were working flat out to fit out their own fleet and none could be spared.



They were very impressed that they got the equipment for free, but they might have had a different opinion if they actually had to pay for it. 



> HMS Carlisle, a converted AA cruiser armed with these guns, shot down 11 aircraft during the war, the highest score among British cruisers. The Auxiliary AA ship Alynbank, also armed with these guns, shot down six aircraft.


British 4"/45 (10.2 cm) QF HA Marks XVI, XVII, XVIII and XXI

How many planes did Delhi shoot down?

The other factor is that we have the USN making really inflated claims of AA kills with their 5in guns, and that must have swayed RN opinion.


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## RCAFson (Aug 11, 2010)

Juha said:


> Hello RCAFson
> we all know, and have knew a while that you think that RN AA was best of the world in early part of the war, but show by some concrete figures when it did clearly better than USN AA.
> 
> Again the end of your message #218, do you read the chapter 9 of the action report of Enterprise, USN saw the dive-bombers when they were well in their dives, see my Indomitable case on 12 Aug. 42, RN AA succeeded to shoot down max one out of 12 Dive-bombers in similar circumstances. How that shows that RN automatic AA was better than that of USN?
> ...



We have a USN gunnery officer on Yorktown recommending replacement of 5" guns with 40mm, this should tell you something...and we have Enterprise saying that 5" are only effective at long range.

The USN did not think the 1.1" was superior to a pom-pom and for you to argue that USN had better AA in Oct 1942, you would need to prove that the 1.1" was better than a pom-pom, and it simply wasn't. 



> _Anti-Aircraft Protection.
> 
> 1. The fire control radar in ENTERPRISE was ineffective. It is not known whether or not other vessels in the Task Force obtained acceptable results from their corresponding equipment, but the fact remains that no 5-inch fire from any vessel in the Task Force was commenced while the enemy aircraft were at the high altitudes at which these guns were the only ones having the necessary range. *The 5-inch fire was commenced only after that of ENTERPRISE small caliber weapons, and after the first attacking planes were in their dives*._


Action Report: 24 August 1942
This was at eastern Solomons and again the 5" was useless.


The distance of the destroyer screen is based upon whether or not the ships being screened have 40mm AA with SD ammo, if they don't then a closer range is possible, albeit with greater likelihood of damage from FF.

Imagine a TB flying low between two ships armed with bofors or pom-poms, if each engaged the TB, they could easily hit each other with dozens of 40mm shells, and that could do severe damage to an unarmoured ship, like a a destroyer.


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## Juha (Aug 11, 2010)

Hello RCAFson
I'm getting a bit bored, if you can give a concrete examples of RN superior achievements, please give them. I already know what you think, so repeating it is not very producive. And of concrete achievements I mean real ones, not wartime claims.

If you have had read more on the Pacific war, you might know that Buckmaster wasn't Yorktown's gunnery office.

And what the captain of Enterprice said was that 5" fire was most effective when directed against dive-bombers before they reached their push over point and for that one needed HA guns-

Quote:"Imagine a TB flying low between two ships armed with bofors or pom-poms, if each engaged the TB, they could easily hit each other with dozens of 40mm shells, and that could do severe damage to an unarmoured ship, like a a destroyer. "

If the outer screen was 6000y out the VT must flew between screening ships in order to reach the launching point for attack on the escorted vessels. And anyway, screen should have been really far out if one wanted it to be out of range of the heavy AA of excorted vessels. 4"-5" shell would have hurt even more, and there were friently fire cases during air attacks.

Juha


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## Glider (Aug 11, 2010)

RCAFson said:


> They were very impressed that they got the equipment for free, but they might have had a different opinion if they actually had to pay for it.


They did pay for it and guess what, they would have had to pay for the other 60. 



> British 4"/45 (10.2 cm) QF HA Marks XVI, XVII, XVIII and XXI
> 
> How many planes did Delhi shoot down?


No idea but I have always been of the opinion that the RN twin 4in was a very capable gun, something that you have just confirmed



> The other factor is that we have the USN making really inflated claims of AA kills with their 5in guns, and that must have swayed RN opinion.


You can of course support that statement.


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## RCAFson (Aug 11, 2010)

Glider said:


> They did pay for it and guess what, they would have had to pay for the other 60.
> 
> 
> No idea but I have always been of the opinion that the RN twin 4in was a very capable gun, something that you have just confirmed
> ...



Lend Lease was in effect at that time, so the gear was effectively free.


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## Juha (Aug 11, 2010)

Hello RCAFson
from the Eastern Salomon report you gave a link.

on those "useless 5" "

"The 5-inch bursts from this ship appeared to be under the bursts of other ships firing and generally well in line and ahead of the planes. Several planes were noticed attempting to pull away from bursts and others were seen to emerge from bursts on fire, while three planes were reported to have disintegrated as though directly hit. (The use of influence fuzes on 5-inch projectiles would make them devastating against a dive bombing attack). "

Juha


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## RCAFson (Aug 11, 2010)

Juha said:


> Hello RCAFson
> I'm getting a bit bored, if you can give a concrete examples of RN superior achievements, please give them. I already know what you think, so repeating it is not very producive. And of concrete achievements I mean real ones, not wartime claims.
> 
> If you have had read more on the Pacific war, you might know that Buckmaster wasn't Yorktown's gunnery office.
> ...



I provided solid data showing 35+ AA kills for PQ-18

The problem is that you think, that somehow, mysteriously, that the USN could achieve better results with inferior equipment...and that just doesn't make sense. You would have to prove that the 5" guns made a major contribution to the defence, and we know that they didn't. In fact here the South Dakota's Captain's opinion:


> South Dakota fired 890 rounds of 5 inch, 4000 rounds of 40mm, 3000 rounds of 1.1 inch and 52000 rounds of 20mm ammunition during the action. Captain Gatch made the following assessment of the relative effectiveness of each weapon type in bringing down enemy aircraft during the action: 5 inch; 5%, 40mm and 1.1 inch; 30% and 20mm; 65%.[3]
> (3) United States Navy, AntiAircraft Action Summary, July 1942 to Dec 1942 (Information Bulletin No. 22), p111


USS South Dakota (BB-57) - Wikipedia, the free encyclopedia

You don't need 85 degree elevation (on the screening destroyers) to engage the DBs before they dive. although in some cases higher than 40 degs would be better, but this wasn't always the case. In any event it doesn't matter because DP guns just weren't very effective.


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## RCAFson (Aug 11, 2010)

Juha said:


> Hello RCAFson
> from the Eastern Salomon report you gave a link.
> 
> on those "useless 5" "
> ...



Please, it was notoriously difficult to determine AA kills at long range, and if it wasn't the USN would not have been making such inflated claims:



> _Assigning credit to ships for shooting down enemy aircraft proved difficult. Enterprise claimed 15, North Carolina 7, Portland 1, Atlanta none (this despite the excellent 5-inch barrage she maintained over the carrier), Balch 2, Benham none, Monssen 1, Ellet none, and Grayson 1. Undoubtedly overlapping existed in these claims, because all ships, except the North Carolina, which became separated, made it clear that more often than not planes at which they fired also were under fire of other ships of the formation. On the other hand, no "probables" or "possibles" were included in these claims.
> _


HyperWar: The Battle of the Eastern Solomons [ONI Combat Narrative]

I count 27 kill claims. Note that Atlanta claimed none, despite her massive 5" battery.

Of course VT ammo would have made a huge difference.


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## Juha (Aug 11, 2010)

First of all, I had already given the figure 28-31 for LW PQ-18 losses	

And what you gave, I bothered only check the recon plane, because I know LW loss figures, and as I guessed, you simply didn’t understand the table. And even from your list, you have 30-31 plus some possibles, that doesn’t necessary mean 35+ for anyone looking it objectively, especially if you have counted those bombers marked as ?% as lost.

Quote:” Please, it was notoriously difficult to determine AA kills at long range…”

dear, dear, the dive-bombers were in their dives, so not so long-range targets. And if you think that I don’t know that many, probably most wartime claims were inflated, I can assure you that I have been aware on that since mid 60s

And of inferiority of US equipment is only your opinion, sorry. The USN AA achievements which Nikademus and I have given were not claims but real results checked against known Japanese losses.

And again I'm little boring on your cherry-picking and strawman tactics


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## RCAFson (Aug 11, 2010)

Juha said:


> Hello RCAFson
> ...see my Indomitable case on 12 Aug. 42, RN AA succeeded to shoot down max one out of 12 Dive-bombers in similar circumstances. How that shows that RN automatic AA was better than that of USN?



Yes, and as you explained the entire convoy was under attack and the aircraft were not spotted until they started their dives, so no AA support from other ships, whereas the USN carriers were the central focus of each attack and had about a dozen ships ready and waiting to open fire in support. 



> _49. The first attack commenced at 1835 and
> comprised at least 13 torpedo bombers; simultaneously
> an unknown number of high level
> aircraft attacked. An emergency turn was made
> ...


http://www.ibiblio.org/hyperwar/UN/UK/LondonGazette/38377.pdf

Note the lack of AA overclaiming.

The fact that the convoy was also a vital target, greatly diluted the focus of RN AA. In fact Malta may have been lost if the Stukas had sunk the Ohio instead of attacking an armoured carrier!


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## RCAFson (Aug 11, 2010)

Juha said:


> First of all, I had already given the figure 28-31 for LW PQ-18 losses
> 
> And what you gave, I bothered only check the recon plane, because I know LW loss figures, and as I guessed, you simply didn’t understand the table. And even from your list, you have 30-31 plus some possibles, that doesn’t necessary mean 35+ for anyone looking it objectively, especially if you have counted those bombers marked as ?% as lost.
> 
> ...



OK, so the RN claimed 40 and got say 32, while the USN is claiming 27 over Eastern Solomons and getting 4 or 5 with a FF kill, and BTW there was a number of FF kills over PQ-18 as well.

Are you claiming that the quad 1.1" was better than the pom-pom? Because that is what you would have to prove! Even the captain of the South Dakota didn't think the 5" was very effective.


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## Juha (Aug 11, 2010)

Hello RCAFson
Quote:” and as you explained the entire convoy was under attack and the aircraft were not spotted until they started their dives, so no AA support from other ships, whereas the USN carriers were the central focus of each attack and had about a dozen ships ready and waiting to open fire in support.”

As were in Enterprise cases according to the action reports and are you claiming that the HMS Kenya and HMS Charybdis joint claim was bogus one and RN AA got none of the Stukas or what? If you don’t know Charybdis was a Dido Class AA cruiser, as was Phoebe, which sailed behind Indomitable but was distracted by Italian torpedo planes, which it probably thought being a thread to Indo. After all it was a standard tactic to co-ordinate dive-bomber and torpedo-bomber attacks just to confuse AA.


If you reread your own message #228, you see that at least captain Gatch seemed to have high regard on 20mm and maybe even on 1.1”, at least 40mm and 1.1” together, and US ships tended to have more 20mm at that time than RN ships. So USN had more Bofors and 20mm, in that they were better, and would haven’t been surprised if 2 single .5” Brownings were more effective AA weaponry than a RN quad .5”. I have no firm opinion on quad 1.1” because its bad reputation might be partly caused by the fact that it was replaced by excellent Bofors and USN Bofors mounts were clearly more reliable than RN Hazemayers, of course also less sophisticated. 

What was effective depended on who made the valuation, read the action reports you gave links to.

Juha


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## RCAFson (Aug 11, 2010)

Juha said:


> Hello RCAFson
> Quote:” and as you explained the entire convoy was under attack and the aircraft were not spotted until they started their dives, so no AA support from other ships, whereas the USN carriers were the central focus of each attack and had about a dozen ships ready and waiting to open fire in support.”
> 
> As were in Enterprise cases according to the action reports and are you claiming that the HMS Kenya and HMS Charybdis joint claim was bogus one and RN AA got none of the Stukas or what? If you don’t know Charybdis was a Dido Class AA cruiser, as was Phoebe, which sailed behind Indomitable but was distracted by Italian torpedo planes, which it probably thought being a thread to Indo. After all it was a standard tactic to co-ordinate dive-bomber and torpedo-bomber attacks just to confuse AA.
> ...



I don't know where you get claims for Kenya and Charybdis from, perhaps you can state your source? 

It is a fact that over eastern Solomons there were no TB attacks while over Santa Cruz there was coordinated attacks but of course the carrier was the central focus of these attacks, whereas in Pedestal each merchant ship had the same strategic value of a carrier and had equal claim to AA protection.

So now you are claiming that 20mm guns are better than pom-poms?

This is very simple:

5in guns are infective, and the data proved this.
1.1in guns were ineffective prior to Santa Cruz and the data proves this, so it is unlikely that they were suddenly effective at Santa Cruz, and the USN discarded them ASAP.
20mm are somewhat effective in sufficient numbers and the data proves this.
40mm guns are new to Santa Cruz and prove to be very effective and Santa Cruz is the best showing for USN AA.

Against TBs pom-poms are 1/2 as effective as bofors but little different against DBs according to Campbell. The RN has 8 X more 40mm pom-pom than the USN has bofors in the same time frame as Santa Cruz, therefore you are arguing that the 1.1" and 20mm must be superior to pom-pom! This is nonsense and the neither the USN or RN believed that.


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## Juha (Aug 11, 2010)

Quote:” I don't know where you get claims for Kenya and Charybdis from, perhaps you can state your source?”

Already given, but again, Shores’ Malta: The Spitfire Year.

Quote:” in Pedestal each merchant ship had the same strategic value of a carrier and had equal claim to AA protection.,”

Even if in 39 RN didn’t value fighters very highly, in 42 it understood that they were critical for air defence, so your guess is wrong, so long as carriers were inside the general screen, they had one modern AA cruiser and one DD as their personal bodyguards, if they manoeuvred outside the general screen 2 nearest DDs joined them as extras. And the normal position of the carriers was just behind Nelsons and Kenya, so they were given best AA support available.

Quote:” 5in guns are infective, and the data proved this.”

Oh, what data, different captains had different opinions and I have not seen reliable info what AA shot down what. If you took Gatch opinion as a base, he seems to value also 1.1” rather highly but IMHO I would be rather careful with his opinion, which was probably partly clouded with inflated claims made by SD. On USN AA at Eastern Salomons, how effective it was depended somewhat on the source one is looking.

On 1,1” and 20mm, modern US cruisers had 4 quad 1.1” and up to 12 20mm already in Aug 42. IIRC in early 42 RN modern cruisers had as automatic AA usually 2 quad (some had 2 octuple) 2pdr mounts and had probably got some 20mm in lieu of quad .5”s. Difference wasn,t very dramatic and 4 mounts is better than 2 if there were multiple targets. US began Bofors installations during summer 42. And one must remember that in June 42 Yorktown and her escorts did nearly as well as Enterprise and her escort in Oct 42 against appr. 8 Vals. One cannot shoot down 25 out of 16-17, so there was no chance to got as many AA kills at Midway as at Santa Cruz in no circumstances.


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## Glider (Aug 12, 2010)

RCAFson said:


> Lend Lease was in effect at that time, so the gear was effectively free.



Lend lease wasn't free it was more a long term credit without payment up front.

Still waiting for you to support your statement.


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## Shortround6 (Aug 12, 2010)

RCAFson said:


> Everyone keeps saying how the 5"/38 is such a great gun, but where are the kills to prove it? The experience of the USN was that DP weapons could not protect the fleet, and that the real threat to aircraft was automatic AA,
> 
> 
> B. Gunnery
> ...



Why don't you get it straight?

The aircraft carrier guns were the MK 21 pedestal mounted model WITHOUT integral ammunition hoists. 
Rate of fire 12=15rpm (in good conditions) why they didn't have automatic fuse setters I don't know but this mount/fuse setter arrangement is quite different than was used on destroyers after hull number 380. The mark 25 and 30 ring mounts with the hoists also had automatic fuse setters in the hoists.The Cruiser Wichita managed to have 4 of each, I wonder what that ships gunnery officer would have to say about the 5"/38?

We all know the British twin 4" was a good gun mount. Want us to look up action reports from those cruisers were the gun mounts were up to 120 feet from the ammunition hoists to see what happened to the rate of fire once the ready locker ammunition ran out?

Seems like you are picking and choosing your data?


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## Nikademus (Aug 12, 2010)

Juha said:


> Hello Nikademus
> on bombers, I counted also 3 Ju 88A-4s from KG 30, one written off after undercarriage failure during landing, maybe mechanical failure or after effect of battle damage, one missing at Spitsberger and one missing at a square, exact place of which I have not bothered to check. On KG 26 losses there are also few cases in which I have given the benefit of doubt to RN.
> I can find only 3 Bf 109 losses between 13 and 18 Sept, none had anything to do with PQ-18 and one on 19 Sept, shot down in air combat over Murmansk, so most probably by Soviets.
> 
> Juha



Hi J,

I made an error regarding this. Total 2E bombers lost per Bergstrom were 19 bombers (KG-26) and 2 bombers from KG-30 along with the 5 x HE-115's. (total 26 planes). 2 of the 115 losses and 5 HE-111/Ju-88's were claimed by Sea Hurricanes while losing 3 SH to friendly AA. The 109 claims were Soviet and involved related operations during PQ-18. Only one verified [Scharf of 6.JG-5] Apologies for the confusion....should have made it clearer that the fighter claims losses were not directly over PQ-18

Germans made their most effective attack on Sept 13. The Ju-88's made an unsuccessful dive bombing attack followed by 24 x HE-111's with torpedoes and more Ju-88's of KG-26. The original plan was to attack the CVE Avenger, but they were unable to locate her so the 40 merchants of the convoy were attacked instead. In 8 minutes 7 x merchants were sunk. 

The Sept 14 attack this time found the Avenger but were disrupted by a combination of AA and CAP (This is where the Sea Hurricanes made the 5 claims and lost 3 of their own number to their own flak) 14 of the Luftwaffe bomber losses occured on this date. Another attack by KG-30 Ju-88's sank another AK.

Thick cloud cover paused combat till Sept 18 which led to two more AK's being sunk (total 10 x AK)
Luftwaffe losses this day 4 bombers of KG-26/30 and the 2 claimed HE-115's by SH's. 

Effective defense during the 14th and 18th largely thwarted Luftwaffe efforts, making them unable to repeat the success of the smothering attack of 13th.


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## Nikademus (Aug 12, 2010)

For continued giggles, here's what i had recorded for AA out of the Pedestal operation (including pre-attack period) via Shores;

8/9

1 x Sunderland 

8/11

1 x Ju-88

8/12

2 of 7 lost Ju-88's claimed by AA
1 x Sea Hurricane

Evening attack 
1 x Ju-88

Convoy scattered by attacks but only has lost 3 merchants. Night attacks will cause further loss and dispersion. (4)

8/13 attacks on convoy elements

1 x Ju-87 (ita)
2 x Spitfire
3 x S.79

Total estimated AA kill (including friendlies) = 12


AA fire was particularily effective on 8/11 during the morning and afternoon, thwarting the torpedo attack by KG-26 from being pressed home. Coupled with Fighter defense, expertly directed via radar assisted FDO Shores noted that no AK's were lost in the face of large string of attacks by both RA and Luftwaffe to be a good achievement. Unfortunately, the dusk attack by 42 planes (30 x Ju-88, 7 x He-111 escorted by 6 x Bf-110) scored sinking 3 AK's and damaging a Destroyer and two more AK's. This effective attack also had the unfortunate effect of scattering the convoy elements over many miles, setting up the favorable conditions for the night surface MTB and sub attacks that evening.


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## RCAFson (Aug 12, 2010)

The USN claimed *over 200 kills for 1942, including 60 by 5in*:

HyperWar: Antiaircraft Action Summary--World War II

for 250 rounds expended per kill, which is better than they could achieve later in the war with VT ammo!!!

Yet as we've seen, USN action reports and Captain's observations, dramatically call this into question.

For example:


> _Admiral Smith also expressed satisfaction with the personnel performance of the Astoria, as well as that of the two other ships of his command, the Portland and Chester. The Admiral, however, was disappointed with the antiaircraft gunfire. *The performance of the 5-inch batteries, he said, was "uniformly poor," with "much wild shooting.*" The 1.1's and 20-mm. guns, "although extremely wild, were more effective." _


USN Combat Narrative: The Battle of the Coral Sea (p31)



> _*The performance of the 5" A.A. batteries was uniformly poor. There was much wild shooting with no indication of control other than local. Bursts were in most cases short and ineffective. Other than noise effect on morale it may be assumed that this battery was useless for close range melee*.The automatic weapons, 1.1 and 20 m.m. although extremely wild were more effective. At least 85% of the fire observed from these weapons was low and trailing. Failure to lead sufficiently and following the tangent of the tracer trajectory were all too apparent. The only solution is believed to be more practice firing from all angles at high speed towed sleeves. Pointers for 20 m.m. guns should be able-bodied, intelligent, marines, trained in "Duck Shooting."_


HyperWar: Battle of Coral Sea--Task Unit 17.2.2 Action Report

The total AA kills for Coral Sea, Midway, Eastern Solomons and Santa Cruz equals about 40, yet the USN claimed 93 at ES and SC alone:



> _Admiral Kinkaid estimated that 170 to 180 enemy planes took part in the attacks on the Hornet and the Enterprise, and that approximately 133 came within striking range of the 2 carriers. He concluded that the Hornet had been assaulted by 49 planes, antiaircraft knocking out 23, and the Enterprise by 84, of which 33 were destroyed by antiaircraft fire. The Enterprise thus was attacked by almost twice as many planes as the Hornet and, together with her supporting ships, shot down 10 more. Her damage was much less severe, because, unlike the Hornet, she did not have the ill-fortune to receive torpedo hits in her vital engineering spaces at the very outset of the battle._




The total of 246 for the year, means that really huge claims were made elsewhere and yet the only possibility for any large numbers were during a couple large IJNAF raids on Guadalcanal shipping, yet it seems unlikely that naval AA could have bagged more than 25 or so, there. That brings us to something like 65-75 actual kills for the year, and probably only 5 - 10% could have been 5in kills, based upon various expert witnesses, so the USN probably overclaimed 5in kills by a factor 8 or 12 to 1! No wonder the 5in has a reputation as some kind of wundergun...unfortunately it was completely bogus, at least in 1942.


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## JoeB (Aug 12, 2010)

RCAFson said:


> That brings us to something like 65-75 actual kills for the year, and probably only 5 - 10% could have been 5in kills, based upon various expert witnesses, so the USN probably overclaime 5in kills by a factor 8 or 12 to 1! No wonder the 5in has a reputation as some kind of wundergun...unfortunately it was completely bogus, at least in 1942.


There is no way to tell what % of kills were due to 5". I'm not saying the % was higher, but you haven't quoted any solid source to back up that % (nor does one exist, so please don't spam any more with generic sources everyone else can also look up and try to twist it into such an analysis, no such analysis that we can rely on exists; if people on ships could overstate the enemy losses, they could mistate the loss causes for the real enemy losses just as easily). 

OTOH you quoted losses of Axis a/c to RN (and Allied merchant ship) AA, which other more reliable posters have indicated are overstated, but anyway the key point is the same: there's no reliable source as to which of those Axis losses in MTO or North were to heavy AA. Anecdotally at least, a lot seemed to be light AA 'revenge' hits on a/c which completed weapons runs then ditched on the way back or crashlanded at base.

So, did 5"/38's shoot down a mass of Japanese a/c in 1942? no. But I think this is a straw man argument for anyone who has read much about the topic: the issue is the inherent design capability of USN heavy AA v that of other navies, not some claim that it shot down huge numbers of a/c in 1942. Which goes back to my post many pages ago, though a lot of in the interim space is your spam (why not just give links to generic stuff on the web?, I think it's reasonable to take up large amounts of space in a thread with details only if it's something that's not on online in English). Nobody's heavy shipboard AA up to around 1942 shot down a lot of a/c, per any solid evidence. 

Joe


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## RCAFson (Aug 12, 2010)

JoeB said:


> Joe



I provided expert opinion on the matter, and that opinion does not support a 25% kill ratio in 1942 by 5in guns as stated by the USN in their AA summary. This is a forum for *discussion*, and lots of information exists on the web to further the discussion, but because it is available on the web it is not inferior to your private sources, and providing data based upon wartime intelligence gives us some insight into what information was available during the war, and therefore, insight into the data upon which opinions as to equipment effectiveness were based. 

I quoted losses based upon official sources for *combined AA and fighter kills* which have actually proven to be relatively accurate and for PQ-18, about 30 of 40 claims have been confirmed, based upon incomplete records. My whole argument, which you appear to be supporting is that automatic AA, was the most potent aircraft killer, and the RN had the best AAA up to and including Oct 1942.

The whole point of the 5in DP design was to shoot down aircraft and the USN made huge trade-offs, especially on destroyers, in terms of weight and cost to do that, and yet the gun was vastly overrated in terms of AA capability. Sorry if that bothers you, but its the truth. I think providing short snippets from lengthy online sources is useful, but that's just my opinion...


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## RCAFson (Aug 12, 2010)

Nikademus said:


> For continued giggles, here's what i had recorded for AA out of the Pedestal operation (including pre-attack period) via Shores;
> 
> 8/9
> 
> ...



I not sure what's so funny, but I ran through the official despatch and made note of the kill claims:

1-Ju88 - FAA

3 x JU-88 - AA

8 - FAA

1 - FAA

1- TB - AA (prob)

1- TB - AA (prob)

1- JU87 - AA (prob)

9 - FAA

1 - JU88 AA (destoyed by blast)

1- ju87 AA

4 - RAF
-------------
27 total including 5 x AA + 3 AA Probables

http://www.ibiblio.org/hyperwar/UN/UK/LondonGazette/38377.pdf

So the despatch seems to actually understate the number of AA kills and total kills, as stated by Shores.


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## Juha (Aug 12, 2010)

Hello RCAFson
How understated total kills, according to your link to TheLondon Gazette Supplement p 4505 the despatch Chapter 56, FAA fighters claimed 39 certain kills, from Shores we know that RAF claimed at least 14. So even without AA claims the total was clearly over known Axis losses. RN lived up its reputation and stubbornly escorted some of the merchantmen to Malta in spite of very heavy losses to subs, MTBs and heavy air attacks. But shows that that RN AA was clearly better than that of USN? Almost at same time on the other side of globe USN AA shot down at least 8 out of 23 attacking Bettys and spoiled aims of the rest so that they got only one hit on DD Jarvis plus one mortally dam Betty crashed on a transport. Betty was much more vulnerable than LW medium bombers but not necessarily very much more vulnerable than the Italian standard torpedobomber S.79. Both Tagaya (in his Osprey Rikko units book) and Lundstrom agree in the AA kill number. IMHO USN AA did very well, shooting down ⅓ of attacking force and spoiling the aim of almost all others.

Juha


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## RCAFson (Aug 12, 2010)

Juha said:


> Hello RCAFson
> How understated total kills, according to your link to TheLondon Gazette Supplement p 4505 the despatch Chapter 56, FAA fighters claimed 39 certain kills, from Shores we know that RAF claimed at least 14. So even without AA claims the total was clearly over known Axis losses. RN lived up its reputation and stubbornly escorted some of the merchantmen to Malta in spite of very heavy losses to subs, MTBs and heavy air attacks. But shows that that RN AA was clearly better than that of USN? Almost at same time on the other side of globe USN AA shot down at least 8 out of 23 attacking Bettys and spoiled aims of the rest so that they got only one hit on DD Jarvis plus one mortally dam Betty crashed on a transport. Betty was much more vulnerable than LW medium bombers but not necessarily very much more vulnerable than the Italian standard torpedobomber S.79. Both Tagaya (in his Osprey Rikko units book) and Lundstrom agree in the AA kill number. IMHO USN AA did very well, shooting down ⅓ of attacking force and spoiling the aim of almost all others.
> 
> Juha



Sorry, I should have stated that my numbers were from the Pedestal diary of events on pages 4506-4512.

According to your sources how many armoured 2E Luftwaffe TBs with self sealing fuel tanks were shot down by RN AA over PQ-18 on Sept 13 and 14 1942? I count 7 for the 13th and 15 for the 14th according to:
Nordic Aviation During WW2


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## Juha (Aug 12, 2010)

13 Aug 3 plus 2 went missing and one overtuned during landing and suffered 80% dam, plus 1 He 115 missing, easier target because slower. 
14 Aug 3 plus 7 missing plus 1 lost to unk reason at Nordkap, 1 90% dam in wheels up landing because of combat dam plus 1 He 115 because of AA and 2 He 115 lost to unk reasons and 1 He 115 missing. And then of course 3 to fighters and the bomber losses.

Those if I counted correctly.

BTW LW itself counted that it lost in Sept 42 23 torp bombers due enemy action and one without enemy action.

Juha


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## Nikademus (Aug 12, 2010)

RCAFson said:


> I not sure what's so funny, but I ran through the official despatch and made note of the kill claims:



Sigh.....the "giggles" comment refers to the continued comparison between convoy battles like Pedestal and PQ-18 and Santa Cruz. IMO, its rather silly to make in-depth comparisons given the conditional differences. Just trying to inject a little light heartedness.

The link you provided keeps crashing my Adobe viewer but i saw enough to see "London Gazette" which suggests a wartime acessment. The figures i posted are post-war estimates. All in all, i'd say AA did a good job in helping break up/thwart attacks based on Shore's research. Its not all about outright kill losses but as in wartime this seems to continue to cause tunnel vision.


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## RCAFson (Aug 13, 2010)

Nikademus said:


> Sigh.....the "giggles" comment refers to the continued comparison between convoy battles like Pedestal and PQ-18 and Santa Cruz. IMO, its rather silly to make in-depth comparisons given the conditional differences. Just trying to inject a little light heartedness.
> 
> The link you provided keeps crashing my Adobe viewer but i saw enough to see "London Gazette" which suggests a wartime acessment. The figures i posted are post-war estimates. All in all, i'd say AA did a good job in helping break up/thwart attacks based on Shore's research. Its not all about outright kill losses but as in wartime this seems to continue to cause tunnel vision.



Yes, I agree that it is hard to find truly tactically equivalent battles. In the final analysis it comes down to examining the hardware and trying to assess it's capabilities. 

The link was to the Hyperwar site and the despatch was concerning some of the major Med convoy battles. The last part of the section on Pedestal contained a diary of events which states observed rather than claimed kills and it was quite close to Shores's research. If the link is crashing your web pdf viewer you might try download the document and read it from your HDD. It and the other despatches make for fascinating reading, as they contain the official version of events as written by the senior officer in command, however in some cases they are written post war and seem to have been cross checked with available Axis records.


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## parsifal (Aug 13, 2010)

How long after the war were the various marks of the 4.7 in retained in service. How long after the war was the 5/38 retained in service. I think the last Gearing was not finally retired until 1980, or thereabouts. I think the 4.7 basically disappeared in 1945, because the 4.5 DP was a far better proposition.

The 5/38 was replaced because there was no automated version of the gun, AFAIK. The new turrets in the Charles F Adams class were 5/54, with autoloader as I recall, just as an example. 

One further question....what was the maximum elevation that the 4.7 could be loaded. The 5/38 could be loaded from quite high angles of elevation.....


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## RCAFson (Aug 13, 2010)

parsifal said:


> How long after the war were the various marks of the 4.7 in retained in service. How long after the war was the 5/38 retained in service. I think the last Gearing was not finally retired until 1980, or thereabouts. I think the 4.7 basically disappeared in 1945, because the 4.5 DP was a far better proposition.
> 
> The 5/38 was replaced because there was no automated version of the gun, AFAIK. The new turrets in the Charles F Adams class were 5/54, with autoloader as I recall, just as an example.
> 
> One further question....what was the maximum elevation that the 4.7 could be loaded. The 5/38 could be loaded from quite high angles of elevation.....



LoL, I've learned more about naval guns than I really wanted to know...but from what I've learned 4.7in gunned destroyers were phased out fairly rapidly in the RN, but survived somewhat longer in the RCN in the Tribal class. Several L-M class destroyers with the Mk XI 4.7in/50 served in the Turkish navy until about 1970. The Mk XI gun fired a 62lb round to better than 21000 yds.

There were a variety of different QF 4.7in guns. All QF versions used a loading tray and could be loaded at all angles. The 4.7in/40 Mk VIII gun was used on the Nelson class battleships and a few others and featured 90 degree elevation. The Mk IX and XII guns were used on the A through I, O, Q through W, Tribal (1937), J, K, N and Abdiel Classes. The last variant of this gun was given the Mk XXII mounting which gave it 55 degree elevation, but the weight penalty was substantial, going from 8.8 tons for the first 40deg elevation version to 11.6 tons for the 55 deg version per mount. The powered Mk XX twin 40 deg mount weighed 25.1 tons. For reference a USN 5in/38 open mount started at 13 tons, while the 5in twin DP enclosed mount weighed in at 43 tons on a destroyer while the LA twin 5in weighed 34 tons, and the weight saved allowed the destroyers that had the LA twin, to carry 2 x quad 1.1in mounts.

The 4.5in gun had much better ballistics than the 4.7/45 as it fired a heavier, modern shell. With VT ammo and better FC with faster computers, a HA gun made more sense, but also the newer twin 4.5 designs featured an enclosed mounting that was probably a nice feature for a peacetime navy.


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## Glider (Aug 13, 2010)

RCAFson said:


> LoL, I've learned more about naval guns than I really wanted to know...but from what I've learned 4.7in gunned destroyers were phased out fairly rapidly in the RN, but survived somewhat longer in the RCN in the Tribal class.


I think you will find that the RCN Tribals were armed with 8 x 4in which tells you something about the standard 4.7in.



> The 4.5in gun had much better ballistics than the 4.7/45 as it fired a heavier, modern shell. With VT ammo and better FC with faster computers, a HA gun made more sense, but also the newer twin 4.5 designs featured an enclosed mounting that was probably a nice feature for a peacetime navy.




Correct which is why the 4.7in left service almost immediately after the war. The 5in L38 survived in the USN and US Coastguard in serious numbers for decades after the war, which tends to prove the point.


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## Shortround6 (Aug 13, 2010)

parsifal said:


> How long after the war were the various marks of the 4.7 in retained in service. How long after the war was the 5/38 retained in service. I think the last Gearing was not finally retired until 1980, or thereabouts. I think the 4.7 basically disappeared in 1945, because the 4.5 DP was a far better proposition.
> 
> The 5/38 was replaced because there was no automated version of the gun, AFAIK. The new turrets in the Charles F Adams class were 5/54, with autoloader as I recall, just as an example.
> 
> One further question....what was the maximum elevation that the 4.7 could be loaded. The 5/38 could be loaded from quite high angles of elevation.....



I don't think it was a matter of how long the 4.7 was retained in service as much as how fast the or how many times the British tried to "improve" the 4.7 during the war. 
The 4.7 disappeared by 1948-49 because the RN had shifted to the 4.5 back in 1942-43, in the sense that all new constructed ships would have the 4.5. From the Savage/'S" class and after. At the End of the war with the newer ships armed with 4.5s and the older ships with armed with 4.7 being mostly worn out and needing repairs/refits it only made sense for the 4.7 armed ships to be the ones to go in the down sizing. 

Of, course in 1941 or so when the drawings started for the designs the British didn't have the war experience to tell them that higher elevation guns and higher rate of fire weren't worth the cost


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## RCAFson (Aug 13, 2010)

Glider said:


> I think you will find that the RCN Tribals were armed with 8 x 4in which tells you something about the standard 4.7in.



They were converted to destroyer escorts around 1950, and the 4.7in guns were replaced by twin 4in at that point. The twin 4in might have been a better all round mount, but it was also much lighter and this probably helped to counteract the overall weight and top-weight growth.


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## Glider (Aug 13, 2010)

RCAFson said:


> They were converted to destroyer escorts around 1950, and the 4.7in guns were replaced by twin 4in at that point. The twin 4in might have been a better all round mount, but it was also much lighter and this probably helped to counteract the overall weight and top-weight growth.



We can all this one a draw as the last 4 RCN vessels were built with 8 x 4in.


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