Rn vs IJN

[Wild_Bill_Kelso]

The F4F Wildcat fought it to a draw in the very beginning and better than even after more IJN pilots were killed.

The numbers look a little different when you check the actual Japanese losses instead of claims. They did eventually more or less break even with the Japanese. We have posted the real numbers in earlier threads. In most cases incidentally, pilots of both F4F and A6M were killed when their aircraft was shot down.

 

[Alan Stevens]

2 knots isn't 'crippled', and light damage (at the cost of one battleship blown to bits and another heavily damaged) isn't a "kill"

I didn't say it was a "kill" just that it was damage critical enough that the mission to break out and disappear into the North Atlantic was canceled and they needed to dash for port and run the gauntlet of the RN on the way.

Dead man walking so to speak.

 

[Wild_Bill_Kelso]

I didn't say it was a "kill" just that it was damage critical enough that the mission to break out and disappear into the North Atlantic was canceled and they needed to dash for port and run the gauntlet of the RN on the way.

Dead man walking so to speak.

Yeah the other guy called it a 'mission kill'. I still don't think it was crippled by PoW. It was probably doomed as soon as it went into the Atlantic though.

 

[Alan Stevens]

The numbers look a little different when you check the actual Japanese losses instead of claims. They did eventually more or less break even with the Japanese. We have posted the real numbers in earlier threads. In most cases incidentally, pilots of both F4F and A6M were killed when their aircraft was shot down.

But the Japanese pilot training programs were so severe that they produced very small numbers of graduates. They could ill afford the loss of those pilots.

 

[Alan Stevens]

Yeah the other guy called it a 'mission kill'. I still don't think it was crippled by PoW. It was probably doomed as soon as it went into the Atlantic though.

I guess that "crippled" is not really the right word. "Doomed" may well be better.

Kinda like rowing a kayak thru a swamp full of crocodiles.

You may make it thru ok but that is highly unlikely.

 

[Wild_Bill_Kelso]

But the Japanese pilot training programs were so severe that they produced very small numbers of graduates. They could ill afford the loss of those pilots.

Over time, yes, it did start to become telling. The Thach weave helped them break even. Ultimately that did come to matter, but it took a while. And the armor and SS thanks didn't make quite as much difference as we are often led to believe. It did help, but not nearly as much as you might think.

 

[Glider]

A comment about torpedo's and that is the submarine torpedo's of the UK were better than the Japanese, early in the war but beaten into second place towards the end of the war.

At the start of the war the Japanese submarines used a type 95 which on paper looked superb, but was taken out of service because it was unreliable and dangerous. Being a smaller type 93 (21in not 24in) it had to be kept totally free of oil which would cause an oxygen explosion. In turn this led to corrosion and unreliability as there is a lot of humidity and oil in a submarine.
This in turn was supplemented by the type 92 which had an average to poor performance. Then the Japanese got their act together and produced the type 96 and type 95 model 2, which were modified type 95's which used less oxygen and could have a some oil and overcame the unreliability

Early war
UK Mk VIII - Warhead 750lb of TNT, range 5,000 yards at 40 knots
Japanese Type 92 Warhead 661Lb, Range 7650 yards at 28-30 knots

Later War
UK MkVIII** - Warhead 805lb, range 5,000 yards at 45 knots / 7,000 yards at 41 knots
Japanese Type 95 model 2 - Warhead 1,213 lb, range 8,200 yards at 47 knots / 6,000 yards at 51 knots

 

[RCAFson]

In the US Asiatic fleet (the 29 boats in the Philippines) two skippers were either relived or asked to be relieved in the first week or two. Six more had been relieved by the time the remaining boats made it to Australia. Critiques of the operations were many and while they knew about problems with the torpedoes (but didn't know how bad they were) a lot of the problems were lack of realistic training, lack of night training, lack of aggression in general, only 2 boats were on patrol on Dec 7th despite all the warnings.
Turns out the older MK 10 torpedoes used the S boats had a problem with depth keeping but didn't have any of the other problems. This contributed (?) to the S boats making, poor as it was, a significant contribution to the total score.

It seems certain that some of the sub commanders relieved were so treated due to the poor quality of their torpedoes, rather than a lack of aggressiveness.

A comment about torpedo's and that is the submarine torpedo's of the UK were better than the Japanese, early in the war but beaten into second place towards the end of the war.

At the start of the war the Japanese submarines used a type 95 which on paper looked superb, but was taken out of service because it was unreliable and dangerous. Being a smaller type 93 (21in not 24in) it had to be kept totally free of oil which would cause an oxygen explosion. In turn this led to corrosion and unreliability as there is a lot of humidity and oil in a submarine.
This in turn was supplemented by the type 92 which had an average to poor performance. Then the Japanese got their act together and produced the type 96 and type 95 model 2, which were modified type 95's which used less oxygen and could have a some oil and overcame the unreliability

Early war
UK Mk VIII - Warhead 750lb of TNT, range 5,000 yards at 40 knots
Japanese Type 92 Warhead 661Lb, Range 7650 yards at 28-30 knots

Later War
UK MkVIII** - Warhead 805lb, range 5,000 yards at 45 knots / 7,000 yards at 41 knots
Japanese Type 95 model 2 - Warhead 1,213 lb, range 8,200 yards at 47 knots / 6,000 yards at 51 knots

The Mk VIII was introduced in 1927, while Mk VIII** was introduced prewar. The later Mk VIII** had an 805lb Torpex warhead, which was roughly equal to 1200lb of TNT.

 

[SaparotRob]

They lied....................................big time.

I didn't want to add the "winky face".

 

[EwenS]

They lied....................................big time.

Well in terms of what they reported to other nations under the terms of the 1922 Washington Treaty, they lied. But the more important question is whether they set out to deliberately build a ship that exceeded the Treaty limits to thereby gain some advantage over the other signatories, or there was simply design "errors" or weight "mis-estimations".

As I've pointed out before no one had built a ship to a defined tonnage limit before 1922. The ship designers of all nations experienced difficulties in so doing. Add to that that in the 1920s one cruiser design was following hard on the heels of another before the first hit the water, so initial problems took time to be recognised.

Take the USA for example. The following information comes from Friedman's "US Cruisers An Illustrated Design History". The Salt Lake City class were designed at 10,000 tons (with a 200-250 ton margin). Much to the surprise of the designers they came out at 9,100 tons! By the time that became apparent the Northamptons had already been designed, again at 10,000 tons. They came out about 9,300-9,400 tons. Friedman states:-

"The first eight American treaty cruisers all came out underweight, far beyond their designers' expectations. One consequence was excessive metacentric height. The roll was, therefore, both short and deep……"

That led to reduced accuracy of their armament and to SLC breaking her topmast.

It seems to have been 1929 before this was realised and acted on (CA 24 Pensacola was laid down in Oct 1926). The first class after that realisation were the New Orleans class, with the Portlands being modified Northamptons to reduce costs the amount needing to be paid to the civilain yards for their construction. The Portlands came out at around 11,200 tons. The New Orleans class came out around 10,050 tons. Both of these seem to have been reported at 9,750 tons. Wichita was also designed at 10,000 tons but came out at 10,565 tons.

Even before the Treaty ships were built, the Japanese seem to have had problems determining the weight of the ships they were designing. In 1922 the Japanese were working on the Furutaka class and their close sisters the Aoba class (the last of their pre-Treaty cruisers). Designed for a normal displacement of 7,500 tons, they came out about 900 tons heavier. Lacroix & Wells had this to say in their "Japanese Cruisers of the Pacific War" book

"The source of the discrepancy remains obscure. It is certain that it was not deliberate since no treaty at the time of their design limited any displacements, and since the overweight had many adverse effects on performance…."

"The discrepancy could result only from an error in the calculation of effective weights. The calculation of the designed displacement, i.e. the volume of the submerged part of the hull, is easy. On the other hand, the calculation of the total weight of all items in the ship, i.e. the sum of all the components of the hull, machinery, armament, protection fittings, etc., is more delicate. Although the Japanese maintain that the weight calculations of the original design were thoroughly executed, some of them must have been erroneous. Moreover, since the overweight occurred on ships built at two different yards, it seems unlikely that the main fault lay in the construction methods."

By the time that this was apparent the next two classes, the Treaty ships of the Myoko & Takao classes, had been designed and were under construction.

The weight problem in the Myokos only seems to have become apparent in 1928 as the first ship, Nachi, approached completion – 985 tons above modified design and 1,488 tons over the original design. The authors note (with my emphasis):-

"…About a third of the increase was the direct result of the modifications introduced at the request of the Naval General Staff (torpedo armament, additional HA guns, living quarters). The cause of the additional increase remains obscure, just as with the Furutaka & Aoba classes and Yubari. It has been reported that the weight calculations were thoroughly reviewed during the design, and the causes of the changes in weight are simply not known, according to Japanese sources. From the weight distribution data available it seems ..... that the excess weight occurred in the hull, armament, equipment and fittings, and fuel. However, it is hard to believe, as was and is sometimes still stated in Western literature, that the full overweight condition of these ships was a deliberate transgression of the treaty's limits. The additional displacement reduced the freeboard, longitudinal strength, reserve buoyancy, maximum speed, and radius of action."

Design of the Takaos began in 1925, before the overweight problems of the earlier classes became apparent. Some weight saving measures were adopted but they still came out heavy. And the problems again lay in the same areas as the Myokos.

Even the British Admiralty Constructors had difficulties estimating the various weights that went into the County class. They seem to have been fortunate in that some were overestimated and some underestimated while they were able to play with things like ammunition loads. But margins were tight, being 200 tons or so.

So designing these ships wasn't an exact science. Some nations' designers did better than others. How much of that was down to prior experience is anyone's guess.

 

[marathag]

So designing these ships wasn't an exact science. Some nations' designers did better than others. How much of that was down to prior experience is anyone's guess.

But the IJN was always coming out heavy, as your source said, including too much armament and fuel.

Overgunning has disadvantages of course, like the German Destroyers, but more and larger caliber guns, faster with more range, sure looks good on paper.

Myoko ended up similar in displacement and length and beam to the later German Hippers, but faster and longer ranged on similar power for one more main turret, but these were more properly gunhouses, saving armor for a thicker constant thickness belt than the tapered on the Hippers.
It was obvious the design was off, the extra turret and belt meant it had to have gunhouses and an unarmored bridge.They had three more in that class to sort that out, but nope, they kept getting heavier.

 

[SaparotRob]

Wow. They managed to a lot in on only 10,000 tons.

 

[cherry blossom]

...snip...
Myoko ended up similar in displacement and length and beam to the later German Hippers,....snip

This is true but note "ended up". As built the beam was much narrower than Hipper and the design was unsatisfactory. Myoko was built with a beam of 56 ft. 11 inches compared to Hipper's 69 ft 11 inches. It was only over 1939-41 that the Myoko class was bulged to 68 ft.

 

[marathag]

Wow. They managed to a lot in on only 10,000 tons.

Well, full load displacement in 1945 of 16,007 after 16 years of modifications and updates.

Got better 8" guns over the original 7.9"

twin 5" secondary mounts in place of single 4.7" mounts

additional catapult, removal of hangar for the three floatplanes, going from Nakajima Biplanes to the monoplane Aichi 'Jake' Floatplane

(2) quadruple torpedo tube mounts for the Long Lance(reduced from previous (4) from the 1935 refit). Originally had (4) triple mounts

Went from two 7.7 AAA mounts to (8) triple 25mm mounts, (4) twin 25mm (8) single 25mm (2) twin 13mm

Three Radar sets.

Still she was slower than the initial 1929 trials of 36 knots after the bulges added for both torpedo protection and to improve the marginal stability, to 32 knots. Now she had a triple bottom, and better compartmentation with four shafts than the Hippers before the Bulging. During the war, took damage surpassing what Blücher took in 1940 without capsizing quickly
for comparison

 

[SaparotRob]

Well, full load displacement in 1945 of 16,007 after 16 years of modifications and updates.

Got better 8" guns over the original 7.9"

twin 5" secondary mounts in place of single 4.7" mounts

additional catapult, removal of hangar for the three floatplanes, going from Nakajima Biplanes to the monoplane Aichi 'Jake' Floatplane

(2) quadruple torpedo tube mounts for the Long Lance(reduced from previous (4) from the 1935 refit). Originally had (4) triple mounts

Went from two 7.7 AAA mounts to (8) triple 25mm mounts, (4) twin 25mm (8) single 25mm (2) twin 13mm

Three Radar sets.

Still she was slower than the initial 1929 trials of 36 knots after the bulges added for both torpedo protection and to improve the marginal stability, to 32 knots. Now she had a triple bottom, and better compartmentation with four shafts than the Hippers before the Bulging. During the war, took damage surpassing what Blücher took in 1940 without capsizing quickly
for comparison
View attachment 734534

I gotta' start adding "winky" emojis.

 

[marathag]

I gotta' start adding "winky" emojis.

Western nations said the Japanese had poor eyesight. Maybe they leaned into it

Showing list of estimated displacement for the IJN Treaty Cruisers

'Looks like 10,000 to me, how about you, Yoshi'
'Agreed. 10,000'

Both laugh

 

[SaparotRob]

'Looks like 10,000 to me, how about you, Yoshi'
'Agreed. 10,000'

Finally. An answer that makes sense.

 

[don4331]

WNT allowed 2 carriers of up to 33k tons from hulls schedules for disposal at request of USN, but US couldn't build Lexington/Saratoga on that displacement, so they added the 3k tons for torpedo and air defense for existing hulls. So, carriers were launched at 36k tons, but were found to be insufficiently strong and 2k steel was added to strength hull. And 1k tons of ballast had to be maintained on port side to correct list from island. Almost 20% over says USN wasn't innocent on displacement overage. Note: CV-2/3 were almost 48k tons at full load.

Blucher received 28cm hits that removed Bruno turret and one at funnel base, torpedo hits at approximately below Bruno turret and amidships and numerous 15cm hits. The most damaging being the 28cm hit at funnel, which riddled the fully fueled Ar-196 and all fire hoses in area. Gasoline flowed down into 10.5cm magazine and fires - uncontrolled due to damage to hoses, ship being shelled by Norwegian shore batteries and exploding army ammunition resulted in magazine explosion - the straw that broke the camel's back.

I don't see any indication that Myoto class survived equivalent punishment.

For the record: Nachi was 10,500 tons std as launched (if you remove the 250 tons of protection added late to shelter deck, they were as close as anyone to hitting the mark 1st try). Treaty allowed for 3k tons for torpedo and air defense improvement, Myoto class taking advantage of that over their 20 years service doesn't seem any worse than USN.

 

[Shortround6]

I gotta' start adding "winky" emojis.

; + ) =

 

[don4331]

Historically, Seafire was put on hold because there was imminent threat. But in this scenario, there is no reason that FAA orders Gladiators or Fulmars as Supermarine would have capacity to spare. And the Blackburn Firebrand isn't put on hold due to BoB, but would in theory be the FAA fighter/strike aircraft of choice.*

As Spitfire and Hurricane become also runs to Tornado/Typhoon/Tempest, RR would be concentrating on developing Vulture to take advantage of 100 octane fuel with Griffon tagging along. The 1,250 hp Merlin (limit of Merlin II on 100 octane) is consigned to same end of production as Kestrel (i.e. no 2spd, no 2 stage superchargers, etc).

So, FAA could have fighter equal to Corsair ramping up on carriers by beginning of '42.
How does the A6M2 compare to a 370+ mph fighter with 4 - 20mm cannons and 800 mile range?

*I realize there are some intermediate FAA specifications which probably see light of day without lessons from Norwegian campaign, etc. My point is a lot of UK aircraft development got put on hold by being at war - adequate aircraft available today is better than superior aircraft available at some future date. FAA certainly had requirements out there for better aircraft.