Midway with expanded Kido Butai?

[EwenS]

There seems to be some cherry picking of information about a Wasp v other carriers in the above comparisons.

Pre-war everyone’s carriers were limited by the constraints of the various Treaties. That meant:-
1922-1936 a total tonnage limit (135,000 for US & Britain, 81,000 for Japan). The US enshrined that in domestic law which they only increased by 40,000 tons in Second Vinson Act in 1938, when they didn’t need to for international purposes. That US increase allowed the building of Hornet, and an allowance towards Essex.

Add to that limits on individual carrier size (27,000 to 1936, 23,000 thereafter with exceptions for Lexingtons & Akagi & Kaga) but subject to the overall limit.

Wasp was designed to use up the the available Washington tonnage after taking account of what was available by converting Langley CV-1 to a seaplane carrier as permitted by the Treaties, prior to the expiration of the Treaty on 31 Dec 1936. She was being designed when Second London Treaty was being discussed and negotiated and laid down 1 April 1936, just days after that Treaty was agreed. By that time the Japanese had announced their departure from the Treaty system

So here are some numbers from my sources incl Friedman US Aircraft Carriers

Wasp
Standard displacement 14,700 tons
Full load displacement 19,116 tons
Flight deck 727x93 feet
Hangar deck 522x63 feet
Airgroup - 74

By early 1942 her air group consisted of 18xF4F-3, 30xSB2U-2 & 6 TBD-1, total 54. By swapping out the fixed wing F4F-3 for folding wing F4F-4 later in the year and moving to SBD-3 and TBF-1 she was able to increase the airgroup to c65.



Commencement Bay class
Standard displacement ? (Wiki says 10,900 tons)
Full load displacement 21,397 (design 24,275 tons)
Flight deck 501x80 feet
Hangar deck 216x69 feet
Airgroup - 33 (18xF6F, 15xTBM-1)

The Commencement Bay was based on a modified tanker hull, not that of a purpose designed carrier. It would therefore be less efficient space wise for a given tonnage. Unlike a purpose designed carrier the hangar ran for a much shorter length due to the need to accommodate other things. Much of the space under the flight deck aft was taken up with machinery & crew spaces

And for the Japanese ships from the Kagero book on the pair
Soryu (as completed 1937)
Standard displacement 15,900 tons
Full load displacement 18,800 tons
Flight deck 712x85
Hangar deck ?
Air-group - 71 (55 + 16 spares) - A5M4 Type 95 fighters (12+4), B5N1 Type 97 TB (9+3), D1A2 Type 96 dive bombers (27+9), 7 C3N Type 97 recce

Hiryu (as completed 1939)
Standard displacement 17,300 tons
Full load displacement 20,250 tons
Flight deck 712x89 feet
Hangar deck ?
Air-group - 73 (as Soryu + 2 additional C3N)

By 1941, with increasing aircraft size, the air groups comprised 21 A6M, 18 B7N & 18 D3A. Total 57.

It is important to note that Japanese carrier capacity, like that of Britain, was determined by hangar capacity. USN SOP involved deck parks even in pre-war days, thus increasing the numbers able to be carried by a ship of comparable size. And both Japanese ships were designed to be faster than Wasp requiring more powerful machinery. They had over double the installed shp giving an extra 4 knots or so in top speed.

As for the Essex class being a pre-war design, it depends on when you consider WW2 started, 1939 or 1941

The design process started in May 1939, after Hornet was ordered, when there was only 20,400 tons to play with. The design characteristics weren’t signed off until Feb 1940 by which time, unfettered by Treaty considerations from Sept 1939, the design had grown to 26,500 tons standard. It would continue to rise the final 27,100. The Two Ocean Navy Act of mid 1940 allowed the US to build multiple ships of that size. That size increase was intended to provide the capacity for a full 5 squadrons of 18 planes each, but of the much larger & thirstier aircraft being designed for them. Those were the F4U, SB2C and TBF.

The Japanese without Treaty restrictions, moved to a much larger vessel of 26,675 tons standard with the Shokakus laid down in Dec 1937 & May 1938.

 

[Reluctant Poster]

The much touted 'enclosed armoured hanger' actually resulted in all the RN's Fleet Carriers that suffered bomb damage or hanger fires needing to be written off due to structural damage. In each case, the hanger either fed the shock damage down into the hull doing such nice things as bending the keel, or acted as a blast furnace causing a minor hanger fire to turn into a raging conflagration that once again wrecked the hull - see HMS Indomitable and HMS Formidable both constructively wrecked after hanger fires.

The Malta Class abandoned not only the much over vaunted armoured flight deck, but used open hangers as per USN practice.

"More fighters would have been better protection than armour."
D K Brown

Bending the keel is complete nonsense. To heat steel in contact with the heat sink of the ocean to the plastic deformation temperature of steel is physically impossible. What is your source for this?

 

[EwenS]

None of the Illustrious/Implacable class were "written off" or "constructively wrecked".

Formidable was the only one to see no service after completing trooping trips in Feb 1947. But after being repaired in 1941 she served through to 1945 when she suffered two kamikase hits. She was laid up largely unmaintained and was found to be in such poor condition in 1949 that Victorious replaced her for modernisation. But despite all the comments about bent keels, no one has thus far produced any documentary evidence to confirm it. She was the first to be scrapped in 1953.

Illustrious, bombed off Malta in Jan 1941 and probably the worst damaged of all, survived the war despite further damage in 1945 from a kamikaze near miss. Refitted 1945/46 she became a trials and training carrier, continuing in the role until the end of 1954.

Indomitable, bombed in 1942, repaired and torpedoed in 1943, repaired again and kamikazied in 1945 (without the flight deck being penetrated). In reserve 1947-50 she was refitted and served as the Home Fleet flagship before being laid up again in 1953, as the next generation carriers began to enter service.

Post war manning problems meant that they RN preferred to keep the light carriers as operational carriers rather than the armoured carriers, except for Implacable and then Indomitable 1946-53.

As for the Malta class design, it was never signed off by the Admiralty. It began life as a double hangar armoured carrier design, like a bigger Audacious class before a redesign was ordered and the final unarmoured open hangar was produced.

And before being too critical of British carriers just remember both the IJN and the USN adopted the armoured flight deck. While the Midway class remained an open hangar design the hangar sides were protected by the armour of the 5"/54 pedestals. However in comparison with previous US carrier designs, there were far less openings in the hangar sides due to the need for much greater supporting structure for the armoured flight deck. But of course that design was never tested in the same way as the Illustrious class.

 

[Reluctant Poster]

The Soyru and the Hiyru were the same size as the Wasp and like the Wasp were compromised Treaty designs. If we are going to give the Wasp a free pass they get one too.

Here's an interesting size comparison of various WWII carriers. The Soyru was the same size as the much-maligned Ranger which was much the same size as the Wasp.

 

[Thumpalumpacus]

Here's an interesting size comparison of various WWII carriers. The Soyru was the same size as the much-maligned Ranger which was much the same size as the Wasp.

In case others are having the same problem viewing the image I am, I tracked it to this:

 

[Reluctant Poster]

Bending the keel is complete nonsense. To heat steel in contact with the heat sink of the ocean to the plastic deformation temperature of steel is physically impossible. What is your source for this?

This got me thinking about my experiences in the utility business. A big coal fired boiler has a furnace made up of waterwalls which are steel tubes with fins welded to them. The fins are butted together to make an airtight enclosure, the required air for combustion is fed by a number of large fans. The remarkable thing about water wall construction is that the walls are cooled by water running through the tubes at or near boiling point. In a typical 500 MW utility boiler the water pressure is ~2600 psi. Water at this pressure boils at 674 F and this is the cold side of the tubes! The tubes are made of ordinary carbon steel not some super alloy. I compared the composition of SA-210 which is a typical tube material with that of Ducol which is the steel used in British warship construction (and post war merchant ships) and found them to be very similar. Further research found that Ducol has actually been used in boiler pressure parts. Obviously, the steel used in the construction of the carriers can withstand very high temperature without deformation. The idea that a hanger fire could distort the hull is complete nonsense.

 

[Reluctant Poster]

A significant design advantage US carriers enjoyed was their open hanger decks. Explosion and fire was vented, rather than contained.

This myth has been debunked previously in this forum. Others have posted images of US carriers with flight decks bulged up. This does give me the opportunity of reposting the image of Enterprise "venting" most of her forward elevator 400 feet in the air.

 

[GrauGeist]

The Kamikaze struck CV-6 just short of the foreward elevator, the bomb continuing down several decks and detonating in the elevator pit.

If the hangar deck wasn't vented, the explosion would have been amplified, causing more damage than what did occur.

 

[WARSPITER]

This myth has been debunked previously in this forum. Others have posted images of US carriers with flight decks bulged up. This does give me the opportunity of reposting the image of Enterprise "venting" most of her forward elevator 400 feet in the air.
View attachment 706813

I'm glad you put the text in this as at first glance I thought it was a T-72.

 

[Reluctant Poster]

This got me thinking about my experiences in the utility business. A big coal fired boiler has a furnace made up of waterwalls which are steel tubes with fins welded to them. The fins are butted together to make an airtight enclosure, the required air for combustion is fed by a number of large fans. The remarkable thing about water wall construction is that the walls are cooled by water running through the tubes at or near boiling point. In a typical 500 MW utility boiler the water pressure is ~2600 psi. Water at this pressure boils at 674 F and this is the cold side of the tubes! The tubes are made of ordinary carbon steel not some super alloy. I compared the composition of SA-210 which is a typical tube material with that of Ducol which is the steel used in British warship construction (and post war merchant ships) and found them to be very similar. Further research found that Ducol has actually been used in boiler pressure parts. Obviously, the steel used in the construction of the carriers can withstand very high temperature without deformation. The idea that a hanger fire could distort the hull is complete nonsense.

View attachment 706704

I should also have stated the origin of the Formidable hanger fire myth. I have seen this on the internet different forms. Some state a Firefly accidentally discharged its 20mm cannon, others that a Corsaires 's 50cal started the fire. According to Stuart Slade in the anti armoured carrier screed he wrote on the Navweps website the fire occurred and "The heat deformed the hull and that was it." The implication is that it was scrapped shortly after this incident. If this were true the incident occurred post war.
The reality is quite different. There is a kernel of truth in that there was a hanger fire on the Formidable on May 14, 1944. The fire took an hour to put out because the fire curtains had been rendered inoperable by the Kamikaze attack on May 4. Note that the sprinkler system worked indicating it wasn't distorted by the fire. Repairs were undertaken at Sydney as part of a general refit which took a month which was was not unusual (US carriers struck by Kamikazes often went back to the west cost for repairs being out of action for three months, some were repaired at Ulithi taking a month). I compiled a list of kamikaze attacks on US carriers and the time taken to repair them. Note that the 3 months out of service included transit time. Repair likely took about a month.

 

[Reluctant Poster]

The Kamikaze struck CV-6 just short of the foreward elevator, the bomb continuing down several decks and detonating in the elevator pit.

If the hangar deck wasn't vented, the explosion would have been amplified, causing more damage than what did occur.

Here's the USN verdict on venting:

This from

I took the plan of the Yorktown (similar to Enterprise) hanger and superimposed the damage suffered by the Enterprise to illustrate the effect of the explosion. Note the flight deck was bulged (up to 5') directly above the side vents and downstream of the forward elevator. Blast damage occurred for much of the length of the hanger.

 

[GrauGeist]

Here's the USN verdict on venting:

View attachment 707281
This from
View attachment 707282

I took the plan of the Yorktown (similar to Enterprise) hanger and superimposed the damage suffered by the Enterprise to illustrate the effect of the explosion. Note the flight deck was bulged (up to 5') directly above the side vents and downstream of the forward elevator. Blast damage occurred for much of the length of the hanger.

View attachment 707283

Again: the kamikaze's bomb went down several decks and detonated in the elevator well.
This amplified the blast as it was in the well, the explosion had no where to go but up. This how the elevator was thrown clear of the ship.

Here is a link that covers the kamikaze impact, explosion and damage detail, complete with actual diagrams of the damage.

Operations of Kyushu - Battle Damage

Battle damage inflicted on USS Enterprise CV-6, 14 May 1945, off Kyushu, Japan.

www.cv6.org

 

[Reluctant Poster]

Again: the kamikaze's bomb went down several decks and detonated in the elevator well.
This amplified the blast as it was in the well, the explosion had no where to go but up. This how the elevator was thrown clear of the ship.

Here is a link that covers the kamikaze impact, explosion and damage detail, complete with actual diagrams of the damage.

Operations of Kyushu - Battle Damage

Battle damage inflicted on USS Enterprise CV-6, 14 May 1945, off Kyushu, Japan.

www.cv6.org

The website you reference is the one that piqued my interest in the effectiveness of venting (or lack thereof). In particular this statement caught my attention:

The website states that it is the damage report of 14 May 1945 but obviously it is not the full report, therefore I went to my collection of USN damage reports and found the one I referenced "USS Enterprise (CV-6) War History". This turned out to be the same report referred to on the website.

The following are excerpts from the original report:

Note that the flight deck was damaged all the way back to Frame 70

in the right-hand side of the photo you can see the elevator opening.

I have revised my markups of the Yorktown drawings to make it clear that the flight deck bulge was directly above the side openings. The pressure wave from a high order explosion moves in a sphere from the center of the explosion. Each portion of the wave continues to move in a straight line until it hits something. There is no mechanism for a segment of the wave to know that there is a path of less resistance to it to follow. There is a direct line from the explosion to the flight deck. That portion of the pressure wave followed it original trajectory and went right past the elevator and side vents and struck the flight deck with its full energy. It can't make a right angle turn to go out the side vents.

The conclusion of the report is quite unequivocal: