Dive bomber accuracy in perspective.

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Stukas accounted for one cruiser and four destroyers sunk off Crete. One cruiser was sunk by ME-109's in the fighter bomber role (HMS Fiji).
HMS Juno was sunk by bombs from a Cant Z.1007 with Imperial damaged beyond repair a week later.

Yes, ships sent by Admiral Cunnigham to carry out an evacuation of the Army in the full knowledge they were likely to be sunk.
When told he could decline, he tersely replied

'It takes the Navy three years to build a new ship … it will take 300 years to build a new tradition'.
 
Britain placed large orders for the Swiss 20mm Oerlikon in 1939 after negotiations to have Oerlikon improve the original 1934 weapon. Very few (c100) were delivered by the unexpected fall of France in June 1940. Britain also obtained a licence to produce the 20mm Oerlikon in 1939. But it was late 1941 before various difficulties were overcome and British manufactured Oerlikons began to appear in significant numbers.

The USN had also rejected the 1934 Oerlikon. It decided in late 1940 to produce the modified version. This decision was very much influenced by the RN war experience to that point. The first came off the production line in June 1941 and by the end of the year production totalled 379.

As for the 40mm Bofors, Britain placed its first orders in 1937. It also acquired a licence to manufacture them. But modifications had to be made for mass production and initial production of the air-cooled type went to the Army. The RN received a handful in late 1941 (PoW received one). The water-cooled version was fitted to the stabilised Hazemeyer mounting which entered RN service in late 1942 in destroyers and sloops.

US interest in the Bofors existed pre-war but is was early 1940 before a sample was obtained and June 1941 before a licence was obtained. Many changes were then required before it could enter production. The first water cooled twin Mk.2 mount was produced in Jan 1942 and the first quad in April. The first fitting of a twin on a destroyer was in July 1942.

Someone noted above that RN ships sacrificed a set of torpedo tubes to gain more AA. No one mentioned the USN position regarding its pre-war destroyers, only the big Fletchers.

Setting aside the old four stackers, pre-war USN destroyers were designed to fairly tight limits to get those 5x5"/38 DP guns, big directors and many torpedoes. That only allowed them to carry the 4x0.5" weapons as light AA (6 in the initial Bensons). Only the larger 1,850 ton "Leaders" of the Porter and Somers classes, which only had single purpose main armament, got the quad 1.1". Using the early war RN experience, by early 1941 they realised that to get a more effective light AA armament there would have to be sacrifices. So the weight reductions began. First to go was No.3 5"/38. Ships with 4 sets of TT saw them reduced to 3. Ships with 2 sets of TT saw them reduced to 1 in some cases. This allowed the fitting of Oerlikons and then twin Bofors. But it didn't happen overnight. Come the kamikaze crisis in late 1944 / early 1945 more light AA was required and more sacrifices had to be made. That included removal of all the TT in some classes, to gain more twin Bofors and a reduced number of twin 20mm mounts.

By way of example USS Eberle DD430

As built in 1940

1943 - gone are the searchlight platform and No.3 5"/38. Added 2 twin Bofors and 4 single 20mm. Plus radars of course

1945 - gone are the TT. AA armament is now 2 quad & 2 twin Bofors plus 2 twin 20mm. Lighter Mk.28 radar on the director. Even then she was considered weight critical.

Nice informative post. And this is why 1930s vintage dive bombers and torpedo bombers were becomming less ideal by the mid-war (1942 again kind of being the tipping point). Faster more heavily armed planes and new tactics had to be created, with the first appearances of stand off munitions by the last two years of the war.
 
Against ships with tachometric directors and true dual purpose guns, the Stuka was little more than an aerial target.
Fortunately for the Luftwaffe, the RN didn't have either on its Destroyers.

The performance of the Mk37 and Mk30 5" mount as fitted by the USN to some old RN Cruisers they refitted was so much better than anything the RN had in service, the RN placed an order for 142 ships sets to switch it to the RN's standard Destroyer armament, but Pearl Harbor got in the way and it was off the Lend Lease table.

But why no Tachymetric directors on RN Destroyers?
Lessons not learned.

The RAF didn't have dive bombers or torpedo bombers, it's approved method of attacking ships was using medium bombers dropping bombs from altitude. An against such targets, firing box barrages using a 2 axis director was seen as perfectly adequate, they obligingly flew in on a constant bearing and altitude. But dive bombers moved in 3 axes at once. TTP's could minimise the risk of dive bombers to ships, but it needed a cool nerve, sea room, and speed. Against fast moving ships with sea roam, the Stuka was fairly useless, most of its successes was against ships either in or around harbours or tied up alongside.
Even against slow targets at sea, they weren't all that good, see the effort to sink HMS Terror, a slow lumbering Monitor.

Best Destroyers any of the assorted assorted combatants entered the war with for fighting off air attacks? The USN's Fletcher Class proved to be magnificent ships, by 1942, they started acquiring l20mm and 40mm guns too making them formidable adversaries for aircraft.

I think you are heavily overstating the limitations of the Ju 87. They sunk quite a few ships in convoys in 1941-1942 which weren't in any dock, including quite small ones. They also managed to maul British aircraft carriers.

The later US destroyers do seem to have been better armed than most other nations, aside from their terrible torpedoes, US was a little ahead on naval warfare in many ways IMO, (certainly in terms of the carrier fleet, and radar on the battleships). But even US ships were still highly vulnerable to Japanese bombers in 1942 as we know, and were still taking losses in 1943. More guns and the proximity fuse really started to make a difference in the later war but by then the tide had already turned.
 
Looking at the 38 squadron records book there was night torpedo practice on 8 January 1942 and torpedo carrying aircraft were sent to operate on 21/22 January but the convoy was out of range, first torpedo operation might be 21/22 February.

First production of torpedo capable Wellington mark Ic and VIII was in March 1942 with 20 built that month, all up 137 torpedo Ic and 271 VIII.

According to Ross McNeill in Coastal Command losses the Beaufort units lost 36 on operations and 17 not on operations in 1940, then 73 on operations and 20 not on operations in 1941.

According to Lloyds losses of allied and neutral merchant ships to air attack came to 1,671,650 tons to end November 1941, from total losses of 8,421,694 tons. Of the total losses, 115,196 and 1,116,683 tons respectively were of neutral ships. Of course some of the neutral ships were carrying allied cargo.

Allied destroyer losses off France, Valentine on 12 May, air attack and beached. Whitley on 19 May, air attack and beached. L'Adroit on 21 May air attack. Jaguar, Chacal and Orage on 23 May, the first to S-boats, the second to air and artillery attack, the third to air attack. Wessex on 25 May, air attack. Wakeful, Grafton and Grenade on 29 May, S-boat, U-boat and air attack in port respectively. Bourrasque on 30 May, hit French mine while evading artillery fire. Sirocco on 31 May, S-boat. Foudrant, Keith, Basilisk and Havant on 1 June, all to air attack.
 
British pulled a set of torpedo tubes off their ships and mounted an old 3in or 4in gun without any director to at least fire something upward. A few major shell bursts helped the crew think they were at least fighting back.

The US had deliberately sacrificed anti-ship capability with the 5in/38 for AA capability. Of course the long range anti-ship capability that other Navies were obsessed with was largely an illusion. Destroyers (especially before radar) didn't have the ability to spot the fall of shot, good enough range finders or steady enough platforms (less rock and pitch) to effectively fire at long range.
The French and German big destroyers with their 5.5 and 5.9 in guns were really backed into a corner when it came to AA.

So yes, there was a slow trickle of light AA guns sprinkled lightly over the ships of many fleets for several years. But the AA situation of even early/mid 1942 was not the situation of 1940.

Japanese destroyers proved to be pretty damn lethal, mainly with their torpedoes and at night. One shudders to imagine what kind of havoc they would have wrought in the Med if the Germans had captured Suez and linked up with them.
 
There is an analysis of British WW2 destroyer losses here

Headlines




CauseNumber
Gunfire14.5
Ship Torpedo10
Submarine Torpedo35
Aircraft Torpedo5.5
Mine27
Bombs48
Accident12
Other1
Total
153

Notes -

1. One of the aircraft torpedo incidents, Janus in Jan 1944, is more usually attributed to an Hs293 dropped by a Do217. Her sister Jervis was hit and damaged by such a weapon in the same attack.
2. Only 1 other destroyer succumbed to a German air dropped torpedo with 3.5 to the Italians.
3. Of those bombed by aircraft:-
He 111 - 1.5
Ju 87 - 13.0
Ju 88 - 6.5
Hs 293 (probably Do 217) - 3 (plus Janus referred to above)
Unidentified German - 19.5 (includes Wessex sunk by Ju87, Codrington sunk by Me 109, Ithuriel by something bigger than a Ju87 since it involved 2x500kg bombs, taken from other sources)
Japanese - 3
Italian Cant 1007 - 1
Unidentified Italian - 0.5
 
The British also converted a squadron of B-26 Marauders to use (British) torpedoes, as I learned recently. They were the only B-26 unit in the Med to use them, apparently with some success.
Yes they did. It was me that filled that gap in your knowledge. 14 squadron which flew its first Marauder mission in Oct 1942 and scored its first torpedo success in Jan 1943. But now we are moving awat from the early part of the war.
 
It's all part of the story old boy, so long as you make note of what happened when ;)

How effective later war torpedo bombers were against the improving AAA was down to both aircraft performance and very much on the characteristics of the torpedo - how fast it could be released, and how low, and how long the torpedo would run (and how fast). More or less in descending order of importance.

I started another thread on that in here a while back, and the gist was basically that the early war torpedoes mostly had to be dropped from very low, and very slow. The Japanese, the Italians and the Russians of all people seemed to be the best, at least on paper IIRC. They started improving them a great deal in terms of design and construction methods, and doing things like adding little wooden carapace to them with fins to make them survive water landing at higher speed and hit the water the right way.

The restrictions of torpedo release early in the war in part explains the merits of the early torpedo bombing aircraft, like the Swordfish or the B5N, or even the miserable Devastator - the very low stall speed they had allowed them to drop torpedoes low and slow enough so they wouldn't break in half when they hit the water.

To get the most of a much faster plane like a Marauder, a Beaufighter or say, (at the end of the war) a B7N, you need a better torpedo that can hit the water at higher speeds and still work.
 
Lack of development in Germany meant the dive bomber had to be used against shipping as the earlier torpedoes used
were not very good and dated close to WWI. A more useful / modern torpedo wasn't developed until 1941 and wasn't ready
for use until 1942.

In the meantime the only good torpedo available was the Italian Fiume which due to the needs of the Italian Air Force was not
always there in numbers for the Luftwaffe to use.
 
The later US destroyers do seem to have been better armed than most other nations, aside from their terrible torpedoes, US was a little ahead on naval warfare in many ways IMO, (certainly in terms of the carrier fleet, and radar on the battleships). But even US ships were still highly vulnerable to Japanese bombers in 1942 as we know, and were still taking losses in 1943. More guns and the proximity fuse really started to make a difference in the later war but by then the tide had already turned.
Later US destroyers were built without the restrictions of the various Treaties, or wartime exigencies.

The 1930 London Treaty imposed a limit of 1,850 tons on a destroyer (Article XV) with a max of 5.1" guns. Article XVI then placed a limit on the overall tonnage, 150,000 tons for the US and Britain and 105,500tons for Japan. And not more than 16% of the tonnage limits could be used for ships over 1,500 tons. That expired on 31 Dec 1936. But for Britain that meant everything up to and including the Tribals were built to these limits. For the US it was all the 1,500 tonners up to the Benhams plus the leaders of the Porter / Somers classes. For both navies that there were then cost v numbers issues in the run up to war. So tonnages grew to the 1,920 tons of the RN L/M classes and 1,620 tons of the Benson/Livermore classes.

In 1940 the US jumped from the 1,620 ton Benson/Livermore to the 2,100 ton Fletcher, carrying the same basic armament i.e. 5x5"/38 plus 2x5 TT. It is no wonder the Fletcher was able to mount a significantly heavier light AA armament as the war went on without the sacrifices of the earlier classes. Out of that came the 2,200 ton Sumner and 2,400 ton Gearing classes. It is amazing what you can do with a few hundred tons of ship!

For the RN the need was for numbers when war broke out, especially in light of the destroyer losses of 1940 & 1941 (60 ships). So it was the 14 flotillas of Emergency/Intermediate destroyers (1,540-1,730 tons) that had to be ordered and that formed the bulk of the RN destroyer forces in the second half of WW2. It was 1942 before it could once again return to look at a fully fledged fleet destroyer. That became the Battle class of 2,315tons, with 2 twin 4.5" DP mounts, 4 twin 40mm Hazemeyer plus a 4" starshell gun and a few Oerlikons (the latter two items rapidly replaced by another 6 single 40mm/2pdr pom pom). Problem was then delays in delivery of new much improved directors, which meant only 1 ship reached the front line in the Pacific before the end of WW2.

For the Japanese, their destroyers topped out around 2,000 tons except for the Akisuki class. These 12 ships of 2,700 tons were planned as AA cruisers before being given a single set of TT. They completed between June 1942 and Aug 1945. But their main armament consisted not of the earlier 5" guns but 4 twin 3.9"/65 DP weapons better suited to the AA role than anti-ship. Japan too however was forced to revert to producing smaller destroyers just to get the numbers in wartime.

As for radars, the RN and USN were fairly evenly matched during WW2. Where they differed was in how the radars of each navy were optimised for the war that they fought.

As for carrier warfare the US only romped away from everyone else from mid-1943 as the vast carrier building programme began to bear fruit with the Essex and Independence classes reaching the Pacific in numbers. At the beginning of the year there was a single operational carrier in the Pacific, Saratoga. That was why there was a request for the services of a British carrier and why HMS Victorious spent a large part of the year there. By the end of the year they could field 6 fleet and 6 light fleet carriers. It was mid-1943 when Nimitz rewrote the Fleet Orders for carrer operations by multi carrier groups, something the USN had only done previously in a very limited way.

The proximity fuse was first used by the cruiser Helena in Jan 1943. But in WW2 it was only available for 3" guns and above.
 
Later US destroyers were built without the restrictions of the various Treaties, or wartime exigencies.

The 1930 London Treaty imposed a limit of 1,850 tons on a destroyer (Article XV) with a max of 5.1" guns. Article XVI then placed a limit on the overall tonnage, 150,000 tons for the US and Britain and 105,500tons for Japan. And not more than 16% of the tonnage limits could be used for ships over 1,500 tons. That expired on 31 Dec 1936. But for Britain that meant everything up to and including the Tribals were built to these limits. For the US it was all the 1,500 tonners up to the Benhams plus the leaders of the Porter / Somers classes. For both navies that there were then cost v numbers issues in the run up to war. So tonnages grew to the 1,920 tons of the RN L/M classes and 1,620 tons of the Benson/Livermore classes.

In 1940 the US jumped from the 1,620 ton Benson/Livermore to the 2,100 ton Fletcher, carrying the same basic armament i.e. 5x5"/38 plus 2x5 TT. It is no wonder the Fletcher was able to mount a significantly heavier light AA armament as the war went on without the sacrifices of the earlier classes. Out of that came the 2,200 ton Sumner and 2,400 ton Gearing classes. It is amazing what you can do with a few hundred tons of ship!

For the RN the need was for numbers when war broke out, especially in light of the destroyer losses of 1940 & 1941 (60 ships). So it was the 14 flotillas of Emergency/Intermediate destroyers (1,540-1,730 tons) that had to be ordered and that formed the bulk of the RN destroyer forces in the second half of WW2. It was 1942 before it could once again return to look at a fully fledged fleet destroyer. That became the Battle class of 2,315tons, with 2 twin 4.5" DP mounts, 4 twin 40mm Hazemeyer plus a 4" starshell gun and a few Oerlikons (the latter two items rapidly replaced by another 6 single 40mm/2pdr pom pom). Problem was then delays in delivery of new much improved directors, which meant only 1 ship reached the front line in the Pacific before the end of WW2.

For the Japanese, their destroyers topped out around 2,000 tons except for the Akisuki class. These 12 ships of 2,700 tons were planned as AA cruisers before being given a single set of TT. They completed between June 1942 and Aug 1945. But their main armament consisted not of the earlier 5" guns but 4 twin 3.9"/65 DP weapons better suited to the AA role than anti-ship. Japan too however was forced to revert to producing smaller destroyers just to get the numbers in wartime.

As for radars, the RN and USN were fairly evenly matched during WW2. Where they differed was in how the radars of each navy were optimised for the war that they fought.

As for carrier warfare the US only romped away from everyone else from mid-1943 as the vast carrier building programme began to bear fruit with the Essex and Independence classes reaching the Pacific in numbers. At the beginning of the year there was a single operational carrier in the Pacific, Saratoga. That was why there was a request for the services of a British carrier and why HMS Victorious spent a large part of the year there. By the end of the year they could field 6 fleet and 6 light fleet carriers. It was mid-1943 when Nimitz rewrote the Fleet Orders for carrer operations by multi carrier groups, something the USN had only done previously in a very limited way.

The proximity fuse was first used by the cruiser Helena in Jan 1943. But in WW2 it was only available for 3" guns and above.

I would say though in terms of carrier warfare as a whole package, including aircraft, damage control, fleet protection (AAA on the escorting warships) and so on, the US was way ahead of everyone except Japan. The RN had the armored decks on their carriers, but they just never developed their own really effective naval fighters, especially prior to 1943, and the British- made carrier strike aircraft (like Swordfish, Albacore and Skua in the early war, and Barracuda in the later), while effective in the early war were just not up to par (particularly in terms of range, but also in terms of vulnerability). The US supplied the British with Wildcats, Hellcats, Corsairs, Tarpons etc., but always too few and much too slowly, as they were so focused on their own epic struggle in the Pacific.

IIRC the first use of the VT (proximity) fuse in action by the US navy was on 5" guns on the Helena in Jan 1943. USS Enterprize and Saratoga (CVs) also had them at this time. USN estimated that in 1943 VT fuses were 25% of the ammunition expended but caused 50% of the casualties among the Japanese aircraft. The proximity fuse also made a big difference in Europe such as against flying bombs, IIRC. It may have been one of the most important technologies of the war.

 
To get the most of a much faster plane like a Marauder, a Beaufighter or say, (at the end of the war) a B7N, you need a better torpedo that can hit the water at higher speeds and still work.
I've got news for you. The standard British torpedo for the first half of the war was the Mk.XII. Developed from 1935 and introduced to service in 1937, it was used by Swordfish, Albacores, Beauforts, Beaufighters, Wellingtons and even the Marauder and continued in limited use until the end of WW2. They seemed to work perfectly well on virtually every aircraft that used them. Pre-WW2 Britain was developing gear like the Monoplane Air Tail and Drum Control Gear to ensure a tropedo would enter the water just as designed. It was only in 1943 that its successor, the Mk.XV came along, longer with a bigger warhead.
 
I've got news for you. The standard British torpedo for the first half of the war was the Mk.XII. Developed from 1935 and introduced to service in 1937, it was used by Swordfish, Albacores, Beauforts, Beaufighters, Wellingtons and even the Marauder and continued in limited use until the end of WW2. They seemed to work perfectly well on virtually every aircraft that used them. Pre-WW2 Britain was developing gear like the Monoplane Air Tail and Drum Control Gear to ensure a tropedo would enter the water just as designed. It was only in 1943 that its successor, the Mk.XV came along, longer with a bigger warhead.

We discussed this previously in this thread:


According to posts there, the Mark XI and Mark XII both required a maximum drop speed of 150 knots. That's quite slow. They improved this to 250 - 270 knots (very good) by adding a new tail from the Mark XV and making other improvements. This seems to have happened some time in late 1942 or 1943, if you know better by all means enlighten us.

I'm sure Beaufighters, Marauders and Beuaforts could drop a torpedo at 150 kts but they'd be much safer in their torpedo run dropping it at 250-270 knots (or whatever their maximum speed is at sea level).
 
I should point out that 150 kts while slow, is not as slow as some of the others. And it's probably faster than a Swordfish or Albacore can fly, especially with a torpedo attached.
 
But why no Tachymetric directors on RN Destroyers?
Lessons not learned.

The RAF didn't have dive bombers or torpedo bombers, it's approved method of attacking ships was using medium bombers dropping bombs from altitude. An against such targets, firing box barrages using a 2 axis director was seen as perfectly adequate, they obligingly flew in on a constant bearing and altitude. But dive bombers moved in 3 axes at once.
"In 1931 there was a major review of anti-aircraft defense by the Naval Anti-Aircraft Gunnery Committee. This Committee reaffirmed that the primary method of air attack against ships would be by high level bombers and concluded that destroyers 'are not likely to be the object of high level bombing or torpedo attack' and that dive bombing was not likely to be much of a threat. These conclusions were supported by the RAF, whose thinking in 1931 was that dive-bombing was difficult with any but purpose-built aircraft and concluded that this meant that such single-purpose aircraft were unlikely to be used in large numbers.1"

"1. This thinking was not as wrong-headed as it may appear with twenty-twenty hindsight. To put this in the proper perspective of the time; since 1924 the USN had been developing dive bombing as a means of supporting Marine landing operations. This was mainly performed by fighter planes carrying only small bombs, which was correctly seen by the RAF as not being much of a threat to a warship. However, in 1930, the USN tested dive bombers which were capable of carrying a 1,000 lb. (454 kg) bomb, large enough to sink a destroyer and badly damage larger ships. In May of 1931, the USN started purchasing quantities of the Martin BM-series of dive bombers which could carry a 1,000 lb. (454 kg) bomb for about 400 nautical miles. A total of 32 of these planes had been delivered for service use by June 1933. This was enough planes to equip a squadron, Bombing One (VB-1), which was assigned to USS Lexington (CV-2). Not long after this time the German Luftwaffe recognized the potential of dive bombers and started large-scale procurement of these planes. The Japanese followed, beginning development of what would become their highly effective Aichi D3A "Val" dive bomber in 1936. So, although the RAF was partially correct in its 1931 assessment of dive bombers, it badly misread their future employment."

History and Technology - The British High Angle Control System (HACS) - NavWeaps Anyone with any interest in this topic should read this article and the two others from NavWeaps that make up a set.

So, blaming the RAF isn't really accurate. The Royal Navy made essential decisions at just the wrong moment. By January 1939 the Royal Navy was very aware of the problem (see the footnotes in the article).

The of the set consists of:
HACS: A Debacle or Just-in-Time?
From Fellside to Flyplane
USN Anti-Aircraft Fire Control Comparison
 
But why no Tachymetric directors on RN Destroyers?
Lessons not learned.

The RAF didn't have dive bombers or torpedo bombers, it's approved method of attacking ships was using medium bombers dropping bombs from altitude.
This doesn't make sense. The Royal Navy operated torpedo bombers continuously from 1917 and it was well aware of threat they posed to warships. What the RAF might do or not do was irrelevant there.

The naval intelligence kept a close eye on developments in the Japanese and American navies. After all, the Japanese navy was considered the only likely peer competitor. When the USN began deploying anti-ship dive bombers in 1931, the Royal Navy noticed. The introduction of dive bombers by the Japanese more than reinforced the point.

In 1934, the Air Ministry issued specification O.27/34, which called for a carrier-based dive bomber. This hardly reflects the Royal Navy sticking its head in the sand about dive bombers.
 
It seems like there was some kind of bureaucratic disconnect between the RN, FAA, RAF, and the various aircraft manufacturers. Clearly FAA saw the need for dive bombing, Swordfish, Albacore and Skua had the capability to do it, and did in action, and the later Barracuda could do it as well at least in theory.

There was some kind of problem though, and I suspect it was on the level of specs or requirements more than the manufacturers, but they did not produce the aircraft that they really needed in terms of capabilities and performance. And that is indeed odd when you consider the RAF had the Spitfire, the Mosquito, and the Beaufighter.

I have read about it a bit but after a while the names of all the departments and military acronyms and various Lords and peers of the realm gets a bit confusing. Something about battleship commanders being put in charge of the air arm at the last minute or something?
 
The RAF didn't have dive bombers or torpedo bombers.

Really? Maybe you should check with the men who flew these:

Vengeance_bomber_of_12_Sqn_RAAF_in_flight_1943.jpg


RAF_A-36A_1.png


Vildebeest-1.jpg


042377.jpg


yal_Air_Force_Coastal_Command%2C_1939-1945._CH9765.jpg
 

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