Armoured Aircraft Carriers in World War II

 Design intent

Your claim (I know several other authors make this distinction as well) that the entire reason the armoured box carriers came about is because the RN suddenly expected to fight land based aircraft and the USN didn’t have armoured flight decks because they planned carrier-on-carrier battles in the mid Pacific ignores so many facts that I had to do this write-up.

Firstly, the USN Pacific campaign: Your viewpoint does not reflect the reality of what I have researched about that conflict and more specifically the entire buildup to it in the 1930’s. Please check out Norman Friedman’s “Winning a Future War” (download PDF here) about the war gaming the USN did during the interwar period. They were completely aware that they could not defend the Philippines and that they would have to fight a campaign back through the Mandates (all the small islands mandated to the Japanese after WWI). The Japanese had a smaller fleet and central to their final fleet battle ideology was the reduction of the US fleet by submarine, torpedo boat and land-based aircraft as it fought its way through the mandates. The USN were having to plan how to fight through the mandates without losing their fleet numbers advantage before facing the main Japanese fleet. The Marines did substantial planning about how to retake occupied islands as part of the outcome of this game theory. The USN carrier design concept was firmly based in the realisation that they would face land-based aircraft and not just the middle of the pacific carrier vs carrier concept that is portrayed on your site.

The Mandates might not have as much land area as was available in the Mediterranean but if you compare actual numbers of airfields available in the Mandates compared to Sicily and a few strips in North Africa (or the thorn that just Malta presented to the Axis) and the fact that the islands were close enough to each other for substantial reinforcements to be flown in, all the way from Japan if required, by repeated island hoping the magnitude of the threat faced was in no way less than in the Med. (Tokyo residents would testify to how large an air raid could be flown from the small islands of Saipan and Tinian).

Next, the RNs sudden switch from Ark Royal to armoured boxes in 2 years: This is not as easily argued away by a sudden threat of land-based aircraft as you try to make out. I have several issues with it, firstly that the armoured box was a reaction to perceived land-based aircraft threats. The Illustrious class dedicate 2860 t (50% of the total weight of armour) to protecting the hangar sides and beltline above the water against ship fired projectiles (4.5” face hardened armour is used to defeat gun projectiles not aerial bombs). You do not use 3” homogenous armour on top of your hangar and 4.5” face hardened armour on the sides if your main threat assessment is bombs dropped by aircraft. This is a massive investment in protection against enemy ship artillery (and only small calibre ships at that – 6” gun light cruisers) and contributes heavily to the reduced aircraft and fuel carrying ability of that class that limited their usefulness.

Secondly, you use the actual history of WW2 events to justify decisions made in 1934/35/36 when claiming the armoured box carriers were designed because of the perceived threat faced in the Med and North Sea. Italy was perceived as an aggressor there but the French and British already had an agreement in place that the French navy would handle the Med and the RN would handle the Atlantic. That Germany would remove France from the board and take over and operate aircraft from Greece (Crete), Sicily and airstrips on the Libyan coast was not foreseen by anyone back in 1935 and was certainly not being planned for. The fact that Churchill placed such a high priority on fighting for the Med was also not part of pre-WW2 planning. Similarly in the Atlantic, there was absolutely no premonition that Germany would invade and be able to fly aircraft from Norway, Denmark, Netherlands, Belgium and France. The only foreseeable exposure to German aircraft in the North Sea back in 1935 would have been substantially more limited. Only the real events of WW2 created the extreme exposure to land-based aircraft that you use as justification for the decision to build the armoured box carriers – it works in hindsight but does not stand up to a review of what could have been perceived as threats in 1935.

Based on all my reading, the fundamental difference between the aircraft carrier strategies of the RN and USN was founded in the RN assessment that carrier-based aircraft would never be able to compete with land-based aircraft (probably based on the type of aircraft they were requesting and producing and heavily influenced by the FAA being part of the RAF which ignored and underinvested in it during the critical pre-war years) and hence would need protection in an aircraft hangar. The USN (and the Japanese) refused to accept that carrier-based aircraft had to be inferior and set out requirements that resulted in higher performance competitive aircraft (the F4F, F4U and F6F) that were able to match the land-based aircraft that they would have to face.

The USN decided to maximise the number of aircraft that could be carried and operated by their aircraft carriers and compromised on armour location (no armoured flight deck or armoured hangar box but armour on decks lower in the ships) and made sure that they specified high performance, competitive aircraft so that the aircraft carriers could perform missions in any environment. The RN decided that carrier aircraft would always be inferior to land based aircraft and accepted aircraft of lower capability in reduced numbers, instead designing armoured warships that could also accommodate and operate aircraft (the substantial investment in the side armour to protect against enemy cruisers gives some idea of how poorly they regarded their aircraft in being able to protect the aircraft carrier).

The following couple of paragraphs are based on some back-and-forth email communication with Armoured Carriers:

I have read through all the pages on your site describing the initial development of the armoured carriers, it is a very interesting collection. I certainly am not arguing that protection against aircraft bombs was misguided, and it is evident in all 3 nations development of carriers that horizontal armour to protect against aerial bombs was wanted, it was just a question of how to implement it and what sacrifices were acceptable. Horizontal armour was included above the vital space in Ark Royal and the Yorktown class and the Essex class with a 2.5” hangar deck and a 1.5” main deck are definitely armoured carriers - 4150t of it, 3000t of which was horizontal deck armour, 500t more than the armoured carriers had - maybe your website needs to be renamed "armoured box carriers" or "armoured flight deck carriers"?

I had noted the reduction to 1.5" hangar sides on the final 3 carriers (as per your email reply), but I find it interesting that the RN persisted with side armour instead of just extending the flight deck armour to the full width of the ship. The Audacious class also maintained the 1.5" hangar walls where none of the US carriers ever adopted the armoured box concept. Midway and the supercarriers only ever had horizontal armour (outside of belt armour).

Also worth discussing is that the RN built the Colosus class light carriers with no armour at all. These were already in the Pacific at the end of WW2 and would have taken part in the invasion of Japan. Considering the portrayal of how vital armoured carriers were to the BPF surviving kamikaze attacks I am curious as to your take on how the RN made this decision and what the outcome would have been. Also of interest is that the Colossus class covered the RNs full burden of operations in the Korean war from 1950-53 – no armoured box carrier was ever deployed during that war.

Bomb damage effect

In at least five different places on your website, you make mention of the much heavier 2200lb bombs that the armoured box carriers faced (by comparison with the 550lb bombs that were dropped on USN carriers) and you infer that they are substantially more damaging. I believe you are overestimating the blast effect of the PC 1000 bomb (full AP). First let's look at the bombs. The 2200lb PC 1000 had a 350lb warhead (16%) and needs to burst through a 1.5” shell wall. The Japanese 550lb SAP bomb had 133lbs of explosive (24%) but only needs to burst through a 0.7” shell wall. Lots more energy gets taken up bursting open the full AP bombs shell than the lighter SAP bombs shell.

Now let's look at the actual damage. The 2200lb bomb dropped on Illustrious exploded 2ft above the hangar deck. It blew a 5 x 7ft hole in the hangar deck which is a 1" high tensile steel deck. The first 550lb bomb that hit Franklin ricocheted off the hangar deck before exploding just above it. It blew a 6 x 12ft hole in 2.5" of special treatment steel (a structural steel with the equivalent properties of class B armour – armour protection of 15% thicker HTS). The 2.5" hangar deck is only 20% thinner than Illustrious 3" flight deck. I am not for a second denying that the heavier AP bomb can penetrate more armour but that is not the tone of any of the sections of your website where you make this comparison – again you make it very clear that you believe the 2200lb AP bomb is a much more destructive weapon than the smaller 550lb SAP bombs dropped on the USN carriers. The actual blast damage in these two instances (larger hole created in substantially thicker armour plate than the one created in a steel plate) does not support your insinuation at all, if anything the blast damage effect of the 2200lb AP bomb was lower than the 550lb SAP bomb.

The damage in Franklin was also not a one off, the Tiny Tims had the US 500lb SAP bomb as a warhead and the ones that detonated in contact with the hangar also made large holes in the 2.5" STS deck.

I am going to take the bomb damage conversation further because from other pages on your site it seems that you have a lack of appreciation for the damage a bomb blast can do when in contact with armour (even relatively thick armour like the 3” flight deck) and an especially low regard for the blast damage caused by the Japanese 250kg SAP bomb. An extract from the Formidable Kamikaze page “The actual hole ripped in the deck appears from damage control photographs to have been only a few inches wide. The commonly referred to “two-feet square” hole appears to refer to the total size of the spall that was shocked out of the interior side of the armoured plates.”

I am not sure if this is your opinion, or you are quoting a source here, but it is very strongly portraying a point of view of the light nature of damage caused by these bombs. Based on this and other descriptions regarding the other kamikaze attacks I think you believe that the 3” armour flight deck provides far more protection than it actually does. To illustrate actual bomb damage, HMS Barham was hit by a 250kg SAP type bomb (27 May 1941) which detonated on contact with the roof of Y turret. The roof plate of 5” non-cemented armour had a hole 18” in diameter torn in it – that is an indication of the type of mining effect a bomb warhead has when detonating in contact with much heavier armour than the carriers flight deck. On a slightly divergent matter, you also make a point of the explosion happening at the juncture of three armour plates – from an engineering perspective it is clear from the photos that the dishing around the hole is uniform, there are no visible tears between the plate sections, no petalled appearance i.e. the welds held structurally and the armoured plates failed - the fact that the plates met there has nothing to do with the penetration achieved.

The description of the hit on Indefatigable shows even less regard for these bombs, it pushes the narrative that the bomb did explode and slightly dented the flight deck and tore a 6ft x 6ft hole in the unarmoured side of the island. I believe the debate around whether there was a bomb and if it actually detonated (Brown doesn’t credit there being a bomb in Nelson to Vanguard by the way) is well founded based on the lack of damage.

I guess I just struggle to understand how you believe these bomb warheads which tore a 6 x 12ft hole in 2.5" of special treatment steel suddenly produce mild denting when applied to the 3” armoured box flight deck despite the fact that a similar German bomb could put an 18” hole in 5” of armour plate on a battleships gun turret.

Armour Penetration

Armour penetration by bombs is another area that I think has been underappreciated based on your descriptions minimising the 550lb bombs. USS Wasp was hit by a 550lb SAP bomb (not 500lb as per your reply in the comments section - the Japanese use the metric system like the Germans, so it was a 250kg bomb) in a real dive-bombing attack which not one single RN carrier experienced in the Pacific. I say it was a real dive-bombing attack because the bomb was dropped at a high enough speed and a steep enough angle to penetrate the flight deck plus any support structures that it encountered below, the gallery deck, the armoured hangar deck (2.5" of STS) and the second deck structure to then detonate above the third deck. This hit would probably have had the energy to penetrate the RN carriers 3” flight deck (remember the flight deck is a structural steel with class B armour equivalent properties – exactly the same properties as STS and only 20% thicker than the 2.5” hangar deck on Wasp without all the additional decks penetrated).

We then move on to the attack on HMS Illustrious and the mention that the PC 1000 barely penetrated her flight deck (from further emailing you pointed out that this was mentioned in Lillicraps summary of the Norfolk Naval Yard report – I would like to lay eyes on the original of that report). The summary states the PC 1000 barely penetrated the Illustious's flight deck because the structure around the penetration was not distorted – this is completely contradictory to ballistics as far as I am aware. The higher the energy of penetration the faster the armour directly affected by the projectile fails without having a chance to distort the metal around it {this is permanent plastic deformation vs failure}. When a projectile barely manages to penetrate an armour plate there is large distortion around the site of penetration because it happens more slowly with very little excess energy - just look at any images where a projectile has been fired at several plates in a row, the first penetration is very clean, the last one has a very large indentation. I don’t have penetration information for the PC 1000 but the US 1600lb AP bomb AN-Mk1 was tested as capable of penetrating a 3.0" armoured deck from a 330ft release in a 300kt (345 mph) 60-degree dive {reference emailed penetration chart}. Even the 1000lb AP bomb was tested as capable of penetrating a 3.0" armoured deck from a 1600ft release in a 300kt 60-degree dive. Ju-87s routinely dived at angles of at least 60 to 70 degrees and their never exceed speed was over 375 mph (even with speed brakes deployed the Ju-87 would struggle to be slower than 350 mph in a 70-degree dive – gravity would be providing the equivalent of 10 000 hp in this dive, that is a lot of air resistance for any type of dive brake to produce).

Maximum penetration would be achieved by a bomb if it reaches terminal velocity, but this was never an expectation in dive bombing (the US 1600lb AP bomb was rated to penetrate 8" of armour when dropped horizontally from 17000ft - this was still not terminal velocity because it was limited by case strength failure beyond 8”). As per the descriptions and your argument of the Ju-87s dropping lower than their optimum heights, this was typical of all dive bombers dropping against ships where the target is moving, and AA was prevalent. They wanted to pull out fairly close to sea level to minimise exposure and to increase accuracy. However, physics limits the minimum height which is why I do not believe this could have affected the penetration ability as much as is claimed. The acceleration experienced by the pilot/aircraft in a turn = velocity^2 divided by the radius of turn. The Stuka could not go any slower than about 350mph in a steep dive even with the dive brakes deployed. Pullout was limited to 6g (what a pilot could sustain without blacking out) which means a 1400ft radius so probably a drop height of at least 1700 - 2000ft to pull out at a safe distance above the sea.

Pilot. Lieut. W. L. Barnes of Blue Section (Illustrious attack) reports on his attack on a Ju-87 that it pulled out of its dive at about 1000ft which would put the bomb release height at about 2500ft which matches dive bombing reports and my calculations above. The eyewitness statements elsewhere about Ju-87s releasing at 500ft or lower must be written off as error on the observers’ part, it is not easy to estimate aircraft heights especially under those stressful circumstances. A simple physics check of a 500ft bomb release and pullup tells us the aircraft experienced 16g (wings would have failed at this g, never mind the pilot blacking out) doing this manoeuvre in a 350mph dive or for a realistic 6g pullup it was only diving at 210mph – neither of these could have happened in the real world.

The Ju-87 was reported to have dropped the PC1000 in a steep dive (evident from the detonation point in the hangar being virtually in line with the penetration hole in the flight deck above) hence the Ju-87 must have dropped from a minimum height of 1400ft (as it did not crash into the sea afterwards or find a way to disobey the laws of physics). The US 1600lb AP bomb will penetrate at least 3.4” of armour from those release conditions, I would expect better or similar performance from the heavier PC1000. In summary I think I have demonstrated that the PC1000 did more than “barely” penetrate Illustrious 3” flight deck.

German bombs and the armoured carriers

I am perplexed by the confusion described on your webpage around what bomb penetrated HMS Illustrious flight deck and what bombs the Germans had. I have found no issue getting information on the PC 1000 specifications and other German bombs - please see this link:

Or this link

It is a postwar US document that fully details all the German bombs and fuses. Then there is the image you have on the “Illustrious damage overview” page which is clearly a German source and supports exactly the same bomb types. I have even delved into the JU-87-D5 pilots manual and all of these sources agree on the aerial bombs the Germans had during WW2. I read the “X Fliegerskorps” typed action report where they mention a SD1000 but based on all the information we have this must have been a typing error – there is no historical information to suggest that this bomb existed. In terms of WW2 bombs the US, Germans and Japanese had similar bomb types, the British were a bit of an outlier. A general purpose (GP) bomb (German SC) would have an explosive charge ratio of 50 - 60 % of the bomb weight, a semi armour piercing (SAP) bomb (German SD) 27 - 36% and armour piercing (AP) bomb (German PC) 14 - 19%.

In terms of the Illustrious flight deck penetration, it would have to have been an AP or SAP type bomb to get through 3" armour. The PC1000 at 19.8" diameter matches the 21" hole description. Maybe the inconsistency between 19” and 21” you mention is just the difficulty of getting a tape measure into the hole to measure the actual diameter, it is also quite a jagged hole if you look at the image from below. Even if an SD1000 bomb did exist we can discount its use here based on the larger size of the SAP SD type bombs by comparison with the AP PC type bombs because of their higher explosives fill ratio (less dense than steel = more space required). The PC500 has a body diameter of 15" (or 15.6" depending on model) where the SD500 already has a body diameter of 17.5", the PC 1000 steps up to 19.8" so by correlation an SD1000 would have been too large to make the size hole recorded. There are no other German bombs that could have made this size hole that could be carried by a JU-87 (these would have been Ju-87-B or -R, the -D was not in production yet and a Ju-87-B could be loaded with a maximum of a 1000kg bomb which limited fuel and other loading to not exceed maximum take0off weight). The PC1000 is the only bomb that could have been used based on the hole size in the armour and the aircraft dropping it. Fairly clear, isn’t it?

In the attack on HMS Formidable the damage assessment report states that they believe 1000kg SAP type bombs were responsible. However, the hole in the 25lb flight deck was still evident and measurable and is stated to be about 21". This creates a dilemma - not only do the Germans not have a 1000kg SAP bomb, even if they did it would have too wide a body to create this hole (See discussion about a potential SD1000 above). This leaves us with the PC1000 or the SD500 (not sure that a 17.5” body diameter would have been able to create the 21” hole described but with not pictures of the hole in the fight deck it is difficult to judge) as the only correctly sized bombs that could have been dropped by a Ju-87 and penetrated the ship.

In communications you mentioned the SC1000 but the hole was approximately 21" while an SC 1000 is at least 25.5" in diameter and hence was absolutely not responsible for this hit. The SC500 has an 18” body diameter but in this case the bomb penetrated the 25lb Flight Deck, 14lb Upper Gallery Deck, 2.5in timber deck and 10lb plate on the Lower Gallery Deck, 14lb Hangar Deck and exploded between the Hangar and Upper Decks. That is 1.825" (73lb) of plate in total (including the wood equivalent) at a 55-degree angle which increases that to an equivalent of 2.22" of steel plate. As per the penetration charts I sent, the US 1000lb GP bomb would not be capable of penetrating this thickness of steel without the case breaking up causing a failure to detonate. The damage report also mentions splinter holes found up to 48ft away from the estimated point of detonation which supports their estimate of a semi armour piercing type or full armour piercing type. Either a PC1000 or an SD500 was responsible.

In the attack on HMS Indomitable the bomb penetrated the 1.5" high tensile steel flight deck and the 1/4" upper gallery deck leaving a 14" diameter hole. This matches the diameter of the SC250 or the SD250 type bombs. The initial assessment report states that the bombs were 500kg SAP type but the SD500 is too large at 17.5” diameter (SC500 is also larger, even the PC500 is too large).

Then there is the D.U.B.D letter that argues for an SC 250 due to the amount of damage done. The statement made regarding the GP bomb is "the Germany type have just about sufficient strength to give the penetration reported". That the GP bomb has “just about sufficient strength” to penetrate the number and thickness of steel decks mentioned is not at all convincing. “Just about” means that it is close but not there. The fact that the US 500lb bomb is limited to 1.25" of penetration goes a long to show how far away from “just about” the SC250 would have been to achieve the recorded penetration. Also, the point made in the last reply in the damage report on your website regarding bomb fragments travelling as much as 52ft from the point of detonation fully supports it being a SAP type bomb as per the initial assessment in the report – however only the SD250 matches the hole size (SAP bombs with thicker cases produce better fragments at higher energy because of the casing thickness).

As a comparison of the extent of damage a large GP bomb does to a warship, have a look at the image of the Jean Bart after a 1000lb GP bomb was dropped on her by an SBD at Casablanca - you would not have wanted to be floating at sea and have that kind of damage inflicted.

Displacement

It is commonly stated (your website included) that Indomitable and the Implacable class were built to the same 23,000 ton standard displacement limit of the Second London Naval treaty. This is absolutely not the case, and I am going to delve into the issue of displacements and naval treaties first and then demonstrate how far over that limit the ships really were.

Firstly, on the definitions of displacement. Full load displacement is very simply the displacement at the maximum design draft – this is usually physically painted on the hull as a change in colour and is visible in the photos of all these carriers. Standard displacement was very clearly defined in the Washington Naval Treaty of 1922 as follows:

“The standard displacement of a ship is the displacement of the ship complete, fully manned, engined, and equipped ready for sea, including all armament and ammunition, equipment, outfit, provisions and fresh water for crew, miscellaneous stores and implements of every description that are intended to be carried in war, but without fuel or reserve feed water on board.

The word "ton" in the present Treaty, except in the expression "metric tons", shall be understood to mean the ton of 2240 pounds (1016 kilos).”

This definition had no room for ambiguity because it was the basis for the arms limitation treaty. The reason they came up with standard displacement instead of just using full load displacement is because the US and UK ships were designed for longer ranges and hence had larger fuel and reserve boiler feed water capacities and the two nations did not want to be unfairly penalised compared to other powers by them being able to build heavier ships with less fuel capacity within the treaty limits. (In an aside you brought up the US excluding AA ammunition – this was mentioned by D.K Brown in Nelson to Vanguard where he mentions the US were having debates internally about light AAA that was invented after the Washington treaty and whether any new unforeseen equipment {like radar} should be exempt from standard displacement - this not actually used to reduce the standard displacement of any class of ship).

The Washington Naval Treaty, which was in effect from 1923 until 1936 (some items were further tightened by the London Naval Treaty of 1930 but did not impact carriers), restricted both the maximum cumulative tonnage for aircraft carriers (UK & US 135,000 tons) and the maximum standard displacement of an aircraft carrier at 27,000 tons. The Second London Naval Treaty, signed in March 1936, removed the cumulative fleet limits for any classes of ship but included a restriction on aircraft carriers to a maximum of 23,000 tons standard displacement. This was a British proposal based on RN design studies into what type/size of aircraft carrier they wanted to build (capability, cost, number of ships etc.). The Illustrious class were actually not limited by the 23,000 ton displacement limit, this reduced limit was proposed by the British and implemented based on the Illustrious design.

Now to the Implacable class. They have a full loaded displacement of 32,110 tons. They have a fuel capacity of 4,810 tons and avgas capacity of 305 tons (95,000 UK gal). Based on similar warships the reserve boiler feedwater is about 10% of the fuel capacity, so 480 tons. This gives a standard displacement of 26,500 tons (using the exact definition for standard displacement), the increase over the Illustrious class being explained by the ship being slightly taller (71ft vs 68ft), the addition of a 20 ft section in the middle of the hull and an extra engine and shaft. I am well aware that treaty limits were null and void by the time they were commissioned but the inference is made that their design was compromised by having to remain with the treaty limits and at 3,500 tons (15%) over the 23,000 ton limit this is clearly not the case.

HMS Indomitable had a full load displacement of 29,730 tons. Fuel capacity =4,520 tons (300 less than Illustrious), avgas = 250 tons, RBFW = 450 tons. This gives a standard displacement of 24,500 tons, also substantially over the treaty limit she was supposedly built to.

while lighter than the Implacable class was more then 1,000tons heavier in full displacement than the Illustrious class, this while carrying 300tons less fuel oil.

As the Essex class are often used as a point of comparison and it is inferred that their larger aircraft compliment is because of they were not being designed within treaty limits and hence could have a much larger displacement I will do that comparison now. By the end of WW2 the full load displacement of the Essex class had increased to 36,700 tons. They had a fuel capacity of 7,100 tons @ 96% of maximum capacity (hyperwar website has detailed fuel usage figures for most USN ship classes), reserve boiler feed water of 515 tons and avgas capacity of 720 tons. This gives a standard displacement of 28,365 tons. This is definitely bigger than the Implacable class (1,865 tons) but not by the substantial margin implied by a 23,000 ton standard displacement.

I would also point out that the above figures still include munitions, aircraft, fresh water, personnel and provisions for them, so does not represent the built weight of the ships. The Implacable class weights for these are; munitions = 750 tons, aircraft (& spares) = 330 tons, fresh water = 250 tons, personnel & provisions = 590 tons, total = 1,920 tons. The Essex class; munitions = 1,550 tons, aircraft (& spares) = 590 tons, fresh water = 570 tons, personnel & provisions = 1,100 tons, total = 3,810 tons. The hull weight with all armament and equipment, Implacable class = 24,580 tons, the Essex class = 24,555 tons. If you delve into the numbers more deeply it becomes evident that the Essex class are slightly lighter in an equipped hull comparison which is very relevant to building cost, building time and shipyard capacity which would all have been limiters on the maximum number of aircraft carriers that could be built during WW2.

Debunking Slade and Worths armoured carrier essays

I have another few points on your debunking page. I will not try to defend Slade or Worth in terms of errors of fact and the lack of time they put into their article by comparison with your website and response, but I do still agree with most of their points. I have a couple of issues with your replies to Worth below.

1) Regarding aerial kills at Okinawa "The rest is a matter of 'statistical deceit':- Let’s look at the raw kill statistics: Britain had about 19 kills per carrier in its Sakishima Gunto assignment. The USN fleet had 126 kills per carrier on the above figures (which may not be apples-with-apples time period). The authors keep reminding us how much bigger the US carrier air wings were... So, given that the British carriers had about one-third the comparable number of fighters, the 126 kill comparison figures comes down to about 40 per comparable grouping of fighters. Once the contribution of the un-mentioned US escort and light fleet carriers is deducted from this total (for apples-with-apples, fleet-carrier to fleet carrier comparisons) - this ratio will become even lower."

I am intrigued by this post because it is the one and only time on your website that you ever credit the USN carriers with having the number of operational aircraft that they did instead of trying to argue that a significant number were "spares". In fact, you swing around too far, stating RN carriers had 1/3rd the number of fighters. We know that the BPF started Iceberg with 151 fighters, 37.75 per carrier. By your argument the US carriers had 3x as many = 113.25 fighters per carrier - very generous of you. Realistically though we have records that show they carried 70 - 72 fighter aircraft per Essex carrier, Enterprise was lower as she was a smaller carrier and being operated as a night fighter carrier by this point.

From their individual records there were no more than 9 USN fleet carriers on station (probably closer to 8 average) during Apr, May & Jun for the month on average (due to battle damage - as you like to point out - and refits). The Naval Aviation Combat Statistics document I shared with you (I wish this level of record keeping was available from the British - the US did manage to keep good records and compile them after the war) records that off Japan and Okinawa from 21 March to 24 May (so the time period is apples-with-apples) the USN fleet carriers (only the fleet carriers, excludes CVL and CVE) destroyed 1255 enemy aircraft in aerial combat. During that same period (25 Mar to 25 May) the BPF destroyed 49 enemy aircraft in aerial combat (this is from the squadron histories on royalnavyresearcharchive.org.uk - I have no idea where Worth got the 126 number from unless he included aircraft destroyed on the ground – the squadron history source for this says 43 aircraft on the ground). The BPF destroyed 0.325 enemy aircraft per fighter, the USN fleet carriers destroyed 1.94 enemy aircraft per fighter (I have used the upper number of fighters 72 for 9 carriers = 648 even though the actual was less than this). That is a factor of 5.9 for the US fleet carriers. If we now allow for the BPF 50% time on station vs 5 of 7 days for the USN it is still a factor of 4.15 for the US carriers. Not the 2 to 1 you claim - 'statistical deceit' maybe.

I am well aware that the US operated in areas where they faced substantially more enemy aircraft, because they were supporting the invasion fleet, which definitely affects the validity of the above comparison but you have never given the US carriers any consideration for this massive difference in the number of enemy aircraft faced when comparing kamikaze outcomes between the RN and USN carriers - always trying to portray them as very similar experiences.

In case you want to try the argument that the BPF spent far more time attacking land targets, they dropped 1,000t of bombs with 216 total aircraft at 4.63t per aircraft while the US fleet carriers dropped 6,643t from 918 total aircraft (102 x 9 carriers) for 7.24t per aircraft - fairly impressive.

At the very end of this section of your reply, you included some information from Henry ‘Hank’ Adlam regarding the operations off Japan in July and August. I realise this is a quoted source but some of the numbers in the table are so wrong that I would question the validity of any of the information. According to the squadron records the BPF destroyed 111 enemy aircraft, not 347 (only 1 in aerial combat). The USN figures are also too high – 1229 vs 2408. The shipping sunk is ridiculously overstated, 356,760 tons for the British TF37 and 924,000 tons for the USN. According to JANAC the British only sank 138,346 tons of Japanese shipping during the entire war and submarines accounted for 61,436 tons of this – carrier aircraft only sank 1,817 tons for the entire war. He is at least consistently equally wrong about the USN, carrier aircraft sank 2,101,477 tons of Japanese shipping but only 308,774 tons during July and August.

2) "What would have become of the British carrier fleet if it had faced the same intensity of attack as the Americans? The prospects are sobering.

I suspect the prospects would not have been quite as sobering as that of a lone US Task Group put in the same position, given the vulnerability of their carriers to internal damage."

Just a quick note on this comment, we have covered the fact that the BPF carriers were not able to be on station for at least 50% of the time, in fact even more when you include their 8-day layover in Leyte. The entire time that they were not on station off Sakishima-Gunto this area had to be covered by TG52.1 Unit Three consisting of three Sangamon class CVEs and one Casablanca class CVE. While I am well aware that they did not have the striking power of the BPF (only 120 aircraft including FM-2s) they were on station in exactly the same area as the BPF for more time than the BPF and they never sustained kamikaze damage while on station there. We don't have to imagine what would have happened to a lone US Task Group put in the same position, there was a US Task Group (of CVEs not fleet carriers) in the same position and the outcome of that is historical record.