Build a better Sea Hurricane 1938

The main problem with getting single seat fighters aboard carriers in 1939 or so was convincing the RAF high command that Germany and/or Japan was actually the enemy.
In the sense that the RAF thought that their real enemy was the RN and the Army who were trying to keep the RAF from it's rightful place as the Defender of Realm for next millennium and every shilling that went somewhere else (the Navy, the Lifeboat service or even the Girl Guides) was a threat to the RAF's mission and existence.
Fighter Command was a costly distraction and if only they could have convinced Parliament that if only the RAF had more bombers they would not even need fighters because no other country would dare to get in war with England and be destroyed by British bomber fleets in a few weeks.
A bit of exaggeration but the RAF was NOT planning on how to most effectively use whatever aircraft they were purchasing. They KNEW that the most effective way to fight a war was with long range bombing and everything else was a distraction. So a minor goal was to keep purchases of non large bomber aircraft to a minimum.

The RN carriers were short of both pilots and aircraft in the late 30s and first years of the war. You need to increase the number of pilots to fly the planes and you need planes. And every squadron of Hurricanes on a carrier (or part squadron) is a squadron of planes that are not defending mainland Britain and shutting up the politicians who are trying to divert the needed bomber engines/props and airframe materials away from where they are truly needed, Bomber Production.
Unfortunately the whole bombers conquer everything theory was just that, a theory. Not only unproven, but not even given the sketchiest of tests.

Fighter Command and the men who lead it and men who did the fighting (including maintenance) pulled the rabbit out of the hat.

There was no technical reason that that a folding Wing Hurricane could not have been in production in 1939 or early 1940.
But without a change in numbers in both the Norwegian Campaign and in the Med in 1940 things would not have changed much.
The Fulmar did OK those battles, yes there some times it could not catch some of the faster enemy bombers. But there were times where it was still in the air and still had ammo to stop or break up later attacks. If some of the carriers had gotten 1/2 dozen Hurricanes in addition to the Fulmars things may have been a lot better. But replacing Fulmars with Hurricanes on a one for one basis may not give that large an increase in actual capability.

The Butt Report of Aug 1941 was the first wide spread crack in Bomber Command belief system, which they tried to rebut in their own report. The internal battles last well over another year.

Giving the RN more input in their own aircraft designs doesn't do much good without also giving them more resources (factories) to build them.

As I've pointed out before the standard of navigation training in the RAF interwar was generally poor and, with that service providing most of the pilots, was something the RN had no control over. See chapter 4 of this.

Navigation over the sea once out of sight of the fleet was even harder than over land, especially if the weather was bad (no roads or railway lines to follow!).

It was the RN who provided the Observers who were RN officers, trained in the science of navigation from their earliest days in the RN. Interwar they were part of the ship's crew, remaining on board when a squadron went ashore ready to join the next to arrive. That was something that changed when the RN got control of the FAA.

The TAGs were non-officers, part of the squadron earning extra for being fliers.

In the Skua squadrons, each flight of 3 aircraft generally had 2 aircraft with TAGs and the flight leader with an Observer in the back seat. In Fulmars, with no rear gun, the rear seater was usually an Observer. Observer training was extended to include operation of the radio equipment at some point.

Once the RN got control of the FAA again it could begin to change things. But in May 1939 it still had about 50 RAF pilots (and should have had another 50 had the RAF fulfilled its end of the bargain about supplying personnel). But by then the Fulmar had already been ordered. The pre-war plan intended that these should be returned to the RAF by about mid-1940 as RN recruitment and training of pilots expanded from 1938 and began to bear fruit from then.

The Type 72 Homing Beacon while introduced around 1936 was not a universal fitting immediiately. It was early 1942 before Hermes & Eagle received it for example. The US YE system was a couple of years behind and it was still being added to the equipment in US carriers in 1941.

Type 72 was also limited in range (c70 miles IIRC). And its use was against RN policy of operating in radio silence (the RN WW1 experience produced good results from direction finding). In the Med in 1941 use of radar was limited to daylight hours for the same reasons.

Shortround6 said:

Part of the RN problem was the limited deck capacity of the RN carriers.

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Would the RN have been better off with six more Ark Royals? We lose the armoured flight deck that presumably contributed to their survival from bomb and kamikaze strikes, but we gain a larger air group that may allow for single seat fighters like a folding Sea Hurricane.

Admiral Beez said:

Would the RN have been better off with six more Ark Royals? We lose the armoured flight deck that presumably contributed to their survival from bomb and kamikaze strikes, but we gain a larger air group that may allow for single seat fighters like a folding Sea Hurricane.

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It still doesn't change the interception problem in pre-radar days.

I doubt Ark would have survived the battering Illustrious took in Jan 1941.

EwenS said:

Type 72 was also limited in range (c70 miles IIRC). And its use was against RN policy of operating in radio silence (the RN WW1 experience produced good results from direction finding). In the Med in 1941 use of radar was limited to daylight hours for the same reasons.

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The system avoided direction finding by the use of a narrow beam rotating at a certain speed which the TAG could anticipate.

Shortround6 said:

..

The Butt Report of Aug 1941 was the first wide spread crack...

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Shortround6 said:

The Butt Report of Aug 1941 was the first wide spread crack in Bomber Command belief system, which they tried to rebut in their own report. The internal battles last well over another year.

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an excellent tongue in cheek summary but non the less pretty accurate. I had never seen the Butt Report but now have a copy which I will read over breakfast.

Admiral Beez said:

Would the RN have been better off with six more Ark Royals? We lose the armoured flight deck that presumably contributed to their survival from bomb and kamikaze strikes, but we gain a larger air group that may allow for single seat fighters like a folding Sea Hurricane.

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I always find this quote by Lt Cdr Steadman Treller USN interesting. He was the US "observer" on Formidable in April 1941 (i.e. before she was bombed off Crete in late May 1941).

"If carriers are to be used in an enclosed sea without the support of the shore based fighters. an armored deck is necessary. but it should be thicker than 3". If carriers are to be used for normal purposes, the additional aircraft capacity is more important than armor."

And of course the Illustrious / Implacable classes were designed primarily with operations in Home Waters and the Med in mind. "Normal purposes" of course is a description of how the USN intended to use its carriers in the broad expanse of the Pacific, where it was much less likely to encounter shore based aviation. It's worth a reminder of the timeline for all three main carrier navies which ALL ended up adopting armoured flight decks.

Britain.
The experience from the Abyssinian Crisis of 1935, led to the design of the Illustrious class in 1936 & their being laid down in 1937 with modified versions in 1938 & 1939. The latter sacrificed some of the hangar side armour for more speed and an extra half hangar with more aircraft. The standard displacement of these ships had to comply with the 23,000 ton limit set by the 1936 London Naval Treaty.

Following that came the Audacious class with 4" flight deck armour and the initial 1943 Malta design (broadly an enlarged Audacious). The Malta design became an unarmoured open-hangar design in 1944/45 based on US Pacific experience and pressure from the then Fifth Sea Lord responsible for Naval Aviation, but that was never approved by the Board of the Admiralty. By summer 1945, the former DNC Sir Stanley Goodall noted in his diary, that the incoming Fifth Sea Lord was muttering about the vulnerability of such ships in light of the kamikaze threat (this was around the time Illustrious arrived back in the UK from Australia). Had they not been cancelled a few months later there may well have been another volte face.

Japan
By the end of 1937, the Japanese had their latest carriers - the Shokakus - beginning construction and they had a shadow carrier programme planned to allow them to compete with the US industrial might in the event of war. But as they looked to the future they realised that they would somehow have to protect their unarmoured carriers from the predations of US carriers. So emerged a plan for a 1st line of protected carriers to operate in front of their 2nd line unprotected carriers. Late in 1937 emerged a new outline requirement for such an armoured 1st line carrier, with construction authorised in March 1939. Due to pressures on design capacity, detailed design couldn't begin until late 1939, and lack of shipbuilding capacity meant that she couldn't be laid down until July 1941 (3 months later than planned). And so was born the Taiho.

But the Japanese had been free of Treaty limits before they even began to think about Taiho, so could build a ship about 25% larger than Illustrious. She too got 3" of flight deck armour. It was only in emergency planning post Midway that the plans for new carriers placed the priority on building the unarmoured Unryus before starting a batch of 5 modified Taiho class with armoured flight decks.

USA
Friedman quotes Admiral Laning around 1931 in relation to the design of the 20,000 ton (standard) Yorktown class whose design was then beginning, discussing Naval War College studies.:-

"We formerly thought that by fighting in the air we could get control in the air like we can on the surface, but we find that no number of defensive airplanes can keep off all air attacks...."

And

"Admiral Rock of C & R agreed that flight deck protection would be useful, especially since bombs penetrating the flight deck would destroy the hangars.......The problem, as in later attempts to secure flight deck protection, was the weight required to defeat realistic attacks."

And that is before the significant advances in aircraft performance that occurred in the 1930s!

Friedman again, this time re the development of the Essex class around July 1939 and the possibility of armouring their flight decks:-

"There was also the flight deck to consider; here the proposed standard was the 500-pounder, and the chief advocate was Captain John S. McCain of the Ranger. He actually preferred a relatively small carrier, as long as it could be protected against bombing. Again and again he told the General Board that any U.S. carrier, if her flight and hangar decks were crowded with fuelled and bombed aircraft, was a potential inferno., and that friendly fighters could not guarantee the security of any flight deck. His views were rejected largely because of the physical cost of effective flight deck armor, a cost confirmed by the sheer size to which the succeeding Midway class was driven......Estimates of the cost of an armored flight deck ran as high as two thirds of the air group, a figure that seems plausible in view of the decline in British air groups attendant on the Royal Navy's adoption of armored flight decks after 1936."

This is of course before the USN got to study Illustrious & Formidable at Norfolk in 1941. Between Oct 1939 & Jan 1940 a 27,200 ton (standard) design CV-9G with 2.5" armour on the flight deck was considered (no indication of air group size). At the end of the day it was thinned to 1.5" and placed on the hangar deck to keep the large air group. The Essex was a kind of halfway house between pre-war Treaty limited Yorktowns and the completely unlimited post Treaty Midways, which at 45,000 tons could be given 3" armour over the flight deck between the two centreline lifts. The 1945 USN Fleet Carrier design (about 40,000 tons standard), that remained on paper, also featured 3" of armour on the flight deck. Only postwar did it become clear that modern weapons were seen as being able to penetrate virtually any reasonable deck thickness.


So everyone wanted armoured flight decks in the 1930s and accepted that something had to give to get it. And for the USA & Japan, that meant waiting until they were no longer bound by Treaties.

EwenS said:

So everyone wanted armoured flight decks in the 1930s and accepted that something had to give to get it. And for the USA & Japan, that meant waiting until they were no longer bound by Treaties.

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Good points. If we can have Britain exit the treaties earlier and swap out the Illustrious and Implacable classes with six 38,000 ton Audacious class we'll have the best all round AFD large CAG carrier. Though they are rather short ranged as completed, I assume with more displacement dedicated to protection, machinery and flight ops over fuel load. Now we can have the folding Sea Hurricane or other single seat fighters we want.

Admiral Beez said:

Good points. If we can have Britain exit the treaties earlier and swap out the Illustrious and Implacable classes with six 38,000 ton Audacious class we'll have the best all round AFD large CAG carrier. Though they are rather short ranged as completed, I assume with more displacement dedicated to protection, machinery and flight ops over fuel load. Now we can have the folding Sea Hurricane or other single seat fighters we want.

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But it was UK, who reduced the limit for carriers in LNT '36 from 36k tons (33k tons + 3k tons for "AAA and ASW protection) to 23k tons... (On the other hand, they were putting in caveats to allow Battleship tonnage to increase to 45k tons).

I still don't see where Audacious class changes FAA aircraft choice from Fulmar to Sea Hurricane.

don4331 said:

I still don't see where Audacious class changes FAA aircraft choice from Fulmar to Sea Hurricane.

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The Audacious class' greater aircraft capacity allows for specialized types, so eliminating the need to find a fighter role amongst the two-seaters.

Admiral Beez said:

The Audacious class' greater aircraft capacity allows for specialized types, so eliminating the need to find a fighter role amongst the two-seaters.

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Indomitable at 23000 tons would seem to be a more plausible choice than Audacious at 38000 tons, which was beyond the UK capacity to build during the prewar expansion of the RN,

don4331 said:

But it was UK, who reduced the limit for carriers in LNT '36 from 36k tons (33k tons + 3k tons for "AAA and ASW protection) to 23k tons... (On the other hand, they were putting in caveats to allow Battleship tonnage to increase to 45k tons).

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CARRIERS
See Article IX of the 1922 Washington Naval Treaty.

The limit set was 27,000 tons (first para in Article IX). There was a secondary provision (second para in Article IX) that allowed each nation to build just TWO carriers of up to 33,000 tons and "in order to effect economy" to use hulls of capital ships that would otherwise have been scrapped. But whatever they built had to be done within the overall carrier tonnage allocation (135,000 tons for Britain & the USA, 81,000 tons for Japan).

Britain went to Washington having decided back in mid-1920 that it needed a fleet of 5 modern carriers and the sweet spot size wise was 25,000 tons (125,000 tons of carriers in total). It was the USA that had been working on carrier designs of 35,000 - 36,000 tons at that time. The 33,000 ton exception was to suit them, and then they stretched the rules to use the 3,000 ton (Chapter 2, Part 3 Section 1(d)) reconstruction additions clause to get the Lexingtons. Settling on a 27,000 and not 25,000 ton limit was really neither here nor there for Britain, as the overall limit still allowed it the 5 ships (at the increased figure) it believed it needed. Britain also extracted the concession about allowing all the pre-Washington carriers to be replaced anytime, which affected it more than USA or Japan.

Come 1935, Britain went into the London Conference with Ark Royal under construction, nominally at 22,000 tons (in reality a bit over with hopes of weight savings during construction) while the US had two 20,000 ton Yorktowns under construction with planned air groups of the same size as the much larger Lexingtons. So both nations knew the size of individual ships, purpose designed as carriers, could afford to shrink a bit. Initially Britain argued for a 22,000 ton limit but settled on 23,000 tons. (In the end Ark was declared at 22,500 tons for Treaty purposes as not all the weight savings hoped for were achieved). BUT London 1936 removed the cap on overall tonnage so allowing an UNLIMITED number of these smaller vessels, which suited Britain with its worldwide commitments.

CAPITAL SHIPS
As far as the size of capital ships was concerned, the 1936 London Naval Treaty fixed it, as before, at 35,000 tons, but with 14" guns. The so called "Escalator" clause only covered a reversion to 16" guns should Japan not agree by 1 April 1937 that she would adhere to the new limit, although she was not a signatory. (Article IV)

Japan didn't give the required undertaking so gun size reverted to 16" (too late for Britain to modify the KGV design). By early/mid 1937 the belief was that she would build new capital ships in excess of 35,000 tons (probably around 45,000 tons was envisaged not the 60,000+ ton Yamato monsters they built). July 1937 saw the signatories to the 1936 Treaty agree a new displacement figure of 45,000 tons. That was driven by the USA. Britain had argued for 40,000 tons, based on cost, docking facilities etc, but that was unacceptable to the USA, so Britain reluctantly accepted the higher figure. When Britain did design its next battleships it did so around the 40,000 ton figure (Lion class) while the USA went to the 45,000 ton Iowas.

The thing about the Treaties is that Britain was no longer the world power running the show. To a large extent it was the USA. But close study reveals how adjustments were made along the way to accommodate the requirements of all nations, not just the big three. The only one left feeling it didn't get what it wanted was Japan, because neither the USA or Britain was prepared to grant it what it wanted, parity with them. Ultimately that led to them leaving the Treaty system.

As usual in peace time the various services see each other at times as the enemy and also presenting opportunities to take over some of their duties (budget), the 1920's had seen proposals to revert to the pre RAF arrangements. The German economy was a relatively fixed target, size and distance, or at least the parts deemed needed to be destroyed. Do the bomb accuracy and effectiveness calculations and come up with the bomber force. For the other air power strengths, fighter - how big is the area to defend and how big is the enemy bomber force, how much warning is usually available?, Maritime - how big is the enemy navy, what it is made up of and where will it operate (remembering Faroes, Iceland and Greenland were owned by someone else), Army - start with how big the army is going to be. What non German opponents are likely, given the problems in returning units from Egypt or further away.

Pre WWI the air force did not exist, artillery assumed to have low attrition rates, the army used horses and not a lot of ammunition (machine guns were nice but were obviously likely to use all their ammunition quickly and leave the unit defenceless), only the navy required a large industrial base. Pre WWII the 3 services were all demanding an industrial base to create a modern force.

Planned RAF force structure, from 1.5 bomber squadrons per fighter at home to 1.7. Scheme L had 73 bomber squadrons and 68 non bomber squadrons in Britain, with nearly a quarter of the RAF based overseas, a number that depended on probable non German opponents as well as internal empire security. Scheme L home strength was 1,352 medium and heavy bombers out of 2,373 front line aircraft, parity with the estimated Luftwaffe as of 1 April 1940 required another 13 heavy bomber and 7 fighter squadrons, making home strength 2,693 aircraft, Scheme L required double shifts and would still be 2 years behind the estimated Luftwaffe and was based on estimated production capacity, not financial limits.

Scheme M was 1,260 heavy bomber out of 2,549 aircraft at home, a response to the Munich crisis
(1) the concentration on building up the strength of the fighters forces of the Metropolitan Air Force need whose needs were to be given priority, with Whirlwinds, Tornados and Typhoons.
(2) a reinterpretation of the desired equality in striking power with Germany as the ability to "deliver at least as equal load of bombs at the required range". This lead to the concentration of bomber production on the large high-performance heavy bombers of the Stirling, Halifax and Manchester types.

"... suggested placing of immediate orders for 1,850 fighters, 1,750 heavy bombers and 2,400 other types and that those orders should be repeated later. Authority for the first orders was given in stages - the Cabinet agreed on 7 November 1938 to the placing of orders for 1,850 fighters, orders for the heavy bombers were sanctioned by the Treasury between January and March 1939 and no difficulty was placed in the way of providing the other types of aircraft."

Noticeable shift to the more efficient, in terms of effort per ton of bombs, from light to medium to heavy bombers, the shift in the mix of the reserve squadrons. Then comes the reality of equipping with what was actually being built. GR General Reconnaissance, GP General Purpose, FB Flying Boat


With the over estimation of Luftwaffe strength creating the belief Britain was short of aircraft, starting with the RAF at home and expanding outwards, compounded by the need to help countries in Europe rearm and stay friendly to Britain. The RAAF being required to lease Avro Ansons as they were wanted back, due to the shortages. Everyone was missing out. We know the answer now is along the lines of raiding Bomber Command to strengthen the other forces, cancelling things like Botha, Defiant and Whirlwind to free resources. While the next generation of British naval aircraft ran into the 1940's crisis, if you wanted a type in 1941 it needed to be in production or nearly so in May 1940, otherwise expect long delays similar to the ready to go 6 pounder anti tank gun, ready to go, easier to produce, made to wait while 2 pounder production made up the losses. Seafire II and Firefly first production June 1942 (but it took until January 1944 for monthly Firefly monthly production to hit double figures), Barracuda July 1942, Seafire III with folding wings April 1943, production hit double figures in October. Britain managed to build 507 naval type aircraft in 1939, 480 in 1940, 1,233 in 1941 but that fell to 1,083 in 1942 as the price to phase out the old and bring in the new, production had climbed to 123 in September 1941, down to 52 in July 1942. The figures include types like the Walrus, which the Germans rated so highly they bombed the factory making them 3 times.

When it comes to anti submarine operations how far from land, patrols of choke points versus convoy cover versus running down sighting reports. When Bismarck was found again the RAF sighting report was out by 25 miles, Bismarck's sighting report was out by 80 miles, all up there was a 75 mile difference between the two. Bismarck was located roughly in the centre of the area being searched by Swordfish from Ark Royal, 2 made contact, 1 reporting a cruiser, the other a battleship. If you want out of land convoy cover you really need to home in the aircraft, but the enemy can track the signals.

Butt report on 18 August 1941, part of the reaction was the 25 October 1941 directive to try fire raids. The heavy losses on the 7/8 November 1941 raid on Berlin resulted in a meeting with Churchill the next day, War Cabinet deliberated and on 13 November came the Winter Quarters order, limited operations only. On 10 December 1941 came the directive giving highest priority to destruction of German capital ships. In one sense Bomber Command was fortunate to have the German Fleet at Brest as a target. Bomb tonnage dropped in night raids August 1941 to February 1942, 4083.0, 2788.8, 2943.5, 1892.5, 1571.7, 2284.2, 951.0, tonnage dropped on Germany by night for the same period 3619.7, 1989.1, 2200.1, 1379.4, 790.0, 977.2, 705.3, percentage of effort 80.6%, 88.7%, 71.3%, 74.7%, 72.9%, 50.3%, 42.8%, 74.1%

The internal debate within an organisation never ends, a 1930's edict banning wooden combat aircraft equals no Mosquito. Things were always changing, first GEE operational trial on 11 August 1941 and first used in a main force attack on 8 March 1942, First operational trial of Oboe, French port target, 7 December 1941, first use over Europe 20 December 1942, first Pathfinder attack 18 August 1942. H2S was under development as well. The 14 February 1942 directive about area raids also included using GEE.

If the USAAF put a veto on unescorted long range bombers then most B-29 day raids on Japan would not have been done, the USAAF knew the Japanese had radar, with more warning than the Germans given radar on Okinawa etc. and the B-29 were cruising at about the same speed as the bombers in Europe. Clearly that internal debate continued.

The Fighter Command system had a solid base in the organisation created and used in WWI. Just as the allied armies combined arms tactics in 1918 taught the Germans much, so the German raids on Britain gave lessons to the defenders.

RCAFson said:

Indomitable at 23000 tons would seem to be a more plausible choice than Audacious at 38000 tons, which was beyond the UK capacity to build during the prewar expansion of the RN,

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In what way? The shipbuilding facilities in 1936 were the same as those in 1943. The big naval yards had built or been scheduled to build Admiral class battlecruisers (Hood)/ G3 class battlecruisers / liners like the Queen Mary & Queen Elizabeth. In 1942 there were 19 slips capable of building ships with a waterline length of 750+ feet. From 1943 the choices began to shrink with the Malta class, and the need to transfer the original Eagle from Swan Hunter to VA Tyne because the beam had been increased. The real problem after 1943 with the ship dimensions were the limited docking facilities around the Empire able to dock them for repairs & refits.

Whether the RN would have chosen to push the enveope that far in 1936 is the question. I think it highly unlikely. See below.

Admiral Beez said:

Good points. If we can have Britain exit the treaties earlier and swap out the Illustrious and Implacable classes with six 38,000 ton Audacious class we'll have the best all round AFD large CAG carrier. Though they are rather short ranged as completed, I assume with more displacement dedicated to protection, machinery and flight ops over fuel load. Now we can have the folding Sea Hurricane or other single seat fighters we want.

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Not sure where you got 38,000 tons from because it is in excess of their displacement as completed (36,800 tons standard as redesigned in 1946) and a long way from where they began in late 1941. Remember the British resisted the proposed 45,000 ton battleships limit proposed by the USA in 1937, and opted for 40,000 tons for the Lion class. They are not oing to then build a carrier of virtually the same size. It is worth following the RN thought process and where it led.

Illustrious class - 23,000 tons standard - 1936
Implacable class - 23,500 tons standard - from early 1938 - design modified in the light of war experience before launch.
Indomitable - 23,000 tons standard - modified from Illustrious class during 1938 to incorporate as many features as possible planned for the Implacable.

1940 Supplementary Programme
Included an armoured carrier that was initially to be a repeat Implacable for speed of build. Then came the requests.

More aircraft (64 were sought). New folded width size limits allowed 4 abreast stowage of fighters, but hull volume required a reduction in lower hangar length to provide the necessary accomodation for the greater crew required to support them. Problem was hull volume.
Indomitable sized forward lift (and in March 1941 a larger aft lift was requested)
Revised bomb stowage
Greater petrol stowage.
Wider flight deck (extra 10ft sought)
Increase in hangar height from 14ft to 14ft 6in.
More flight deck armour. To keep out 500lb SAP dropped by a dive bomber from 3,000ft instead of just a GP weapon. That required more beam at the waterline.

All this was thought possible around March 1941 on about 23,200 tons, but seems a bit unlikely given what follows. The order was postponed and the modifications continued to build up as a result of war expeience. Eventually she was ordered in March 1942 but modified still further by which time she bore only a passing resemblance to Implacable. Then later in 1942 it was decided to build her as an Audacious class. She became Ark Royal IV.


Audacious class is born
Then August / Sept 1941 more studies for a new carrier were prepared ranging from 25,000 to 27,000 tons standard displacement. These showed that you could have 2 full length hangars and 3in of flight deck armour OR 1 1/2 hangars and 4in of flight deck armour. But the Admirals wanted both!. From that came a Staff Requirement for the 1942 Fleet Carrier issued at the end of Nov 1941 (highlights only)-

Standard displacement - 27,000 tons
Beam - 104ft
Speed - 31.5 knots
Aircraft - space for 72 (44ftx13.5ftx13.5ft. Note length relaxation from pre-war). Operational facilities for 60
Petrol - 115,000 gals (still considered inadequate)
Hangars - 2 full length; 14ft 6in clear height
Lifts - 2 Indomitable sized serving both hangars.
Flight deck armour - 4in
Hangar sides - 1.5-2in

Detailed design was then undertaken and the new design signed off in Sept 1942 by which time 2 ships had been ordered. But the alterations kept on going. Here is a comparison of the 1942 and 1946 (redesign) figures.

Standard displacement - 31,600 / 36,800 tons
Beam - 108ft 8.5in / 112ft 8.5in (this was required to compensate for the increase in hangar height from 14.5ft to 17.5ft. This decision was made in late 1942 with the realisation that the RN would be dependent on US aircraft for the forseeable future and probably accounts for much of the increase in displacement.).
Speed - 32 / 31.5 knots
Aircraft - 69 (44ftx13.5ftx13.5ft) OR 57 (40ftx18ftx13.5ft) / 40 TBR + 40 FF OR 28 TBR + 50 FF
Armour - flight deck 4"; hangar sides 1.5"

Conclusion
Without the Treaty limit of 23,000 tons I really don't see the RN going to 38,000 tons. More likely you would have seen a carrier with:-

Displacement - c27,000 tons +/- 1,000 tons (In 1920 25,000 was seen as the ideal figure. And with engineering advancements that would deliver far more than in 1920. It also fits with what other nations were looking to by the end off the decade i.e. Shokakus & Essex)
Speed - 32 knots as sought from Implacable
Aircraft - 66 Albacore / Fulmar sized
Hangars - 2 full length
Lifts - 2 (after early 1938 to match Indomitable's forward lift)
Armour - flight deck 3in (matches Illustrious - thicker is a lesson from WW2)
Hangar side armour - reduced to 1.5-2in per Implacable (needed to buy the extra hangar.
Hangar height - that is the question. With two full hangar decks the ship is deeper and the flight deck armour higher. 14ft/14.5ft/16ft? depends on what stability margins would allow. I doubt tthat they would go to the US 17.5ft which was forced on them in WW2.
Visually - something like a cross between an Implacable & an armoured Ark Royal

EwenS said:

Conclusion
Without the Treaty limit of 23,000 tons I really don't see the RN going to 38,000 tons. More likely you would have seen a carrier with:-

Displacement - c27,000 tons +/- 1,000 tons (In 1920 25,000 was seen as the ideal figure. And with engineering advancements that would deliver far more than in 1920. It also fits with what other nations were looking to by the end off the decade i.e. Shokakus & Essex)
Speed - 32 knots as sought from Implacable
Aircraft - 66 Albacore / Fulmar sized
Hangars - 2 full length
Lifts - 2 (after early 1938 to match Indomitable's forward lift)
Armour - flight deck 3in (matches Illustrious - thicker is a lesson from WW2)
Hangar side armour - reduced to 1.5-2in per Implacable (needed to buy the extra hangar.
Hangar height - that is the question. With two full hangar decks the ship is deeper and the flight deck armour higher. 14ft/14.5ft/16ft? depends on what stability margins would allow. I doubt tthat they would go to the US 17.5ft which was forced on them in WW2.
Visually - something like a cross between an Implacable & an armoured Ark Royal

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I'm going to call it RN-'35max as the 27k ton limit was still in place and UK could have started a CV then and forced the LNT '36 had it been desired:

Given the conditions of the time wouldn't the CV be more the "1b" version of '41 carrier study? By '41, with Radar (and war conditions), the risk of bumping into light forces at night is greatly reduced.

On 27k tons ± 3k tons
Armour: (all values matching Illustrious as there isn't radar and the 'threat' in the North and Mediterranean Seas is that Destroyers/Light Cruisers can travel further during hours of darkness than the flights can have scouted before night falls)
This proposal is to match exceed the "Outrageous" class hanger capacity, which a hanger and a half should do. (36 + 18) > 48. Close enough to the 50-60 of Ark Royal.
The armour is still going to restrict hanger height to 13' for both, again original value for Illustrious and a requirement of the Albacore design.
It will need 3 lifts to be efficiently to provide primary and alternate to both hangers (2nd lift between lower and upper hangers doesn't necessarily have to penetrate flight deck). Aft lift may be enlarged should it be desired.
To make the desired 32kn speed, it will need 4 shafts.

And it still doesn't answer "How do you keep every Sea Hurricane coming off the assembly line from being turned over to RAF/VVS through fall of '41".

EwenS said:

In what way? The shipbuilding facilities in 1936 were the same as those in 1943. The big naval yards had built or been scheduled to build Admiral class battlecruisers (Hood)/ G3 class battlecruisers / liners like the Queen Mary & Queen Elizabeth. In 1942 there were 19 slips capable of building ships with a waterline length of 750+ feet. From 1943 the choices began to shrink with the Malta class, and the need to transfer the original Eagle from Swan Hunter to VA Tyne because the beam had been increased. The real problem after 1943 with the ship dimensions were the limited docking facilities around the Empire able to dock them for repairs & refits.

Whether the RN would have chosen to push the enveope that far in 1936 is the question. I think it highly unlikely. See below.

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Because the RN was already building to capacity in the immediate prewar period and there simply wasn't the needed steel, armour and labour needed to build 38000 (or slightly smaller) ton carriers in any timely fashion. OTOH, if the design for Indomitable had been put forward in lieu of that for Illustrious, then it shouldn't have presented any difficulties over and above the historical situation.

don4331 said:

I'm going to call it RN-'35max as the 27k ton limit was still in place and UK could have started a CV then and forced the LNT '36 had it been desired:

Given the conditions of the time wouldn't the CV be more the "1b" version of '41 carrier study? By '41, with Radar (and war conditions), the risk of bumping into light forces at night is greatly reduced.

On 27k tons ± 3k tons
Armour: (all values matching Illustrious as there isn't radar and the 'threat' in the North and Mediterranean Seas is that Destroyers/Light Cruisers can travel further during hours of darkness than the flights can have scouted before night falls)

3" Flight deck
2½" Hanger deck (Everyone seems to forget this 2nd armoured deck on Illustrious).
4½" Hanger side armour (This might get relaxed for more hanger height)
4½" Belt​

This proposal is to match exceed the "Outrageous" class hanger capacity, which a hanger and a half should do. (36 + 18) > 48. Close enough to the 50-60 of Ark Royal.
The armour is still going to restrict hanger height to 13' for both, again original value for Illustrious and a requirement of the Albacore design.
It will need 3 lifts to be efficiently to provide primary and alternate to both hangers (2nd lift between lower and upper hangers doesn't necessarily have to penetrate flight deck). Aft lift may be enlarged should it be desired.
To make the desired 32kn speed, it will need 4 shafts.

And it still doesn't answer "How do you keep every Sea Hurricane coming off the assembly line from being turned over to RAF/VVS through fall of '41".

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To clarify the armour layout on Illustrious see the Armoured Carriers page that draws on Ross Watton' s Anatomy of the Ship HMS Victorious.

Flight deck between the lifts 3"
FD around the lifts 1.5"
Remainder unarmoured

Hangar deck level:-
Outside the hangar walls 3" amidships, fore and aft 1"
The hangar floor within the hangar walls 1"
The objective was to produce an armoured box protected from above and the sides.

The 1,000kg bomb that punched a neat hole in her 3" flight deck armour in Jan 1941 exploded just above the hangar floor and the blast and splinters penetrated the hangar floor. Hit iidentified as No.6. From the Armoured Carriers site.

"The warhead went on to burst inside the hangar space just 2ft above the 1in strengthened steel hangar deck. It ripped open a 4ft wide hole in the 1in strengthened steel Hangar Deck on the centreline between 128 and 132 stations. "
Scan down the page about half way on the attached link to get the armour layouts.

don4331 said:

The armour is still going to restrict hanger height to 13' for both, again original value for Illustrious and a requirement of the Albacore design.

Click to expand...

Missed this last night. Clear hangar height under the beams:-

Illustrious class - 16ft
Indomitable - lower hangar 16ft, upper hangar 14ft
Implacable - 14ft upper & lower hangars.

1942 the Admiralty decided to move to the US standard 17.5ft to accommodate forthcoming US aircraft types that it was going to have to rely on. So Colossus class light fleet carriers got 17.5ft and the Audacious design was modified in late 1942 to increase it from 14.5ft to 17.5ft.

As it was, the Hurricane and its naval variant has to be the best fighter with a fabric covered fuselage. This category includes the likes of the Rogožarski IK-3, Koolhoven F.K.58 and Fiat CR.42.