1936 (cont)
At the London Naval conference, the Admiralty had set out its minimum requirements for the talks; a displacement limit of 25,000t per carrier (although if really pressed they would go to 24,000t, any lower didn't give the capacity and protection they thought acceptable), and either a high total displacement or (as in the Washington treaty), no limit on numbers on smaller carriers -10,000t as a bare minimum, 12,000t if at all possible.
Discussions with the USN showed that the Americans wanted to press for 20,000t as the carrier maximum, as this was the size they thought suitable for their new carriers. It was pointed out by DNC that the USN only had to design the ships for one area of use and one opponent, and that they were prepared to accept carriers relatively unprotected to get the number of planes they wanted on a 20,000t ship. The extra 4,000 - 5,000t of the British carriers was mainly protective, as these ships would have to operate in the North Sea and the Med, and also that the poor weather in the Atlantic made it desirable to house the normal complement of aircraft under cover in the hangers rather than on deck; if Ark Royal was to use a deck park, DNC was confident she could operate 100 planes, notably more than the US carriers.
It came as a surprise to the Admiralty when they were given the final agreement for the new naval treaty, in that they got everything they wanted and more. It was rumoured that some members of the FAA staff took a day to sober up after reading the proposal... There would no longer be any limitations on the total displacement of aircraft carriers, and the maximum for a carrier would be 24,500t (while this was slightly more than the Formidable, it was expected to be no huge issue getting a few hundred tons off her weight.
As a result of the ending of overall displacement limits, the RN and the FAA undertook a complete reappraisal of their options. It would now be possible to fill their needs without being bound by treaty, although there would still be the treasuries financial constraints.
After considerable deliberations, the future needs committee came up with the following requirements.
First, fleet carriers would be needed to work with and cover the most likely deployments. These were Home Fleet (covering Germany), the Med (covering the Italians), and in the Far East (covering Japan)
The German threat was seen mainly as heavy ships attacking convoys. They had 3 pocket battleships and some heavy cruisers, which could be engaged by RN cruisers and heavy ships, and 2 (with 2 more building) fast battleships, which could only be stopped by the RN battleline. The expected counter to these ships was twofold; first, hunting groups to be deployed early in the war to hunt existing raiders (it was assumed that the longer range units would have been sent out in advance of a declaration of war), and a strong Home Fleet to bottle up the ships in German ports. While the navy was confident they could destroy the German battleships if they could catch them, they needed some way of both finding them and slowing them down. It was considered that a force of 3 carriers with the Home fleet would be needed (as one might be undergoing repairs or refit , and the Germans could come out at any time).
While these would ideally be fleet carriers, it would be practical to have one be a light carrier, as in this situation they were unlikely to be encountering the Luftwaffe. The number of carriers needed by the hunting groups was, again ideally, around 6, to have one with each group. This was felt unlikely to be achieved (in the short term), so this was set at 3, which would be deployed in the areas most difficult for land-based air support.
In the Med, it was considered that the western end was reasonably secure due to probable French support from land-based air, although a carrier would be based at Gibraltar as part of a hunting group. The eastern Med had more area to cover, and would be working in range of the Italian airforce, so a fleet carrier was considered essential.
The Far East was a more difficult area to evaluate. It was felt that the land-based air threat would normally be minimal due to the ranges involved, and for operations close to land our own air cover would be to hand. The problem was evaluating how many carriers of the IJN would be needed to be neutralised. In the end the ideal cover was thought to be 2 fleet carriers and 2 light carriers, the light carriers allowing air support for lighter striking forces than the main fleet.
This made a total of 5 fleet carriers and 5 light carriers, plus another fleet and light carrier to allow for refits. This of course made no allowance for reserves, losses and the need to reinforce a high threat situation - it was thought that in the event of war in the Far East, 5 fleet carriers would be needed, plus 3 at home, which implied 10 fleet carriers alone (allowing for those temporarily out of service). After considerable discussion as to the operational uses of a protected fleet carrier against a lighter, smaller carrier, he total needed was set at 8 fleet carriers and 8 light carriers.
There was also the issue of convoy protection. The RN had been steadily working out how to run and protect convoys. Air cover was seen as useful for 3 main purposes; locating a surface raider so the convoy could evade, or protection could be reinforced, covering the convoy against air attack and driving off search aircraft looking for the convoy, and conducting A/S sweeps in front of and around the convoy.
The direct air threat was seen as minimal in the Atlantic, as current planes simply didn't have the range to get there from Germany (although in a WW1 type situation, and with the constant improvement of aircraft, this might change, at least in the eastern Atlantic), and coastal convoys would be covered by the RAF where necessary. The Med was more complex, but unlike the Atlantic convoys would be minimal and directly escorted, so the fleet units would probably be sufficient. In the Far East it was felt the air threat was minimal due to the distances involved.
Surface raiders were seen as a threat in all oceans except the Med, but because of that support would only be practical for high value convoys
The submarine threat was again likely anywhere (although most likely in the Atlantic and the Med), but this wasn't currently seen as the main threat (they were more worried by the surface raider threat), although it was acknowledged that air cover would seriously reduce the threat of submarine attack.
The problem was availability; the existing analysis already required far more carriers than were available (and more than the treasury was likely to fund), and the demand could be quite high. What was needed was a very cheap ship that could carry the minimum number of planes needed. The current CVL's were costing about £1.8M (as opposed to about £4 for a fleet carrier), and they would like if possible to get the price down to around £1M. DNC were asked to provide some layouts and costings for a ship with the following capabilities; it would be in the 10-12kt size (it was felt anything smaller wouldn't be suitable for use in the Atlantic), no armour, minimal self defence, carrying a squadron of 12 TBR + 4 fighters, with space for an addition 4TBR and 2 fighters to cover damage. Maintenance support would be minimal (damaged planes would be offloaded and replacements put on). Speed would be ideally 24kt (which would actually allow them to support the older battleships), and also be useful when being used as a plane transport, but 20-21 kt was seen as adequate, especially if this reduced the cost. Manpower requirements should be kept to a minimum.
The Admiralty (and Chatfield in particular), was still very worried about what they saw as the lack of armour on the CVL class. They had agreed, reluctantly, that HMS Colussus would build to a light, only partially armoured design, because the carrier was seen in part to be used for training. However they worried about its lack of protection. The large fleet carriers were seen as being adequately protected, if somewhat light on side armour, and a number of studies were done on the possibility of a small protected carrier (carrying the 25 planes of the Colussus class). These showed that the penalties of armour were very expensive, both in terms of weight and aircraft. A carrier with deck armour and a TDS built for a similar purpose would come in at around 17,500t, and be slower and carry less aircraft, although it would have heavy AA guns. More worrying was the cost; Ark Royal was costed at £3.8M, and Colussus at £1.8M, giving them a similar cost per plane carried, but the small armoured carrier would cost £2.8M. This was not seen as efficient compared to the Ark Royal class. The obvious answer was to build more fleet carriers (even if it was necessary to lower operating costs by reducing the number of aircraft carried. A study was authorised to see what was possible for a budget of £1M (an interesting divergence as usually the Admiralty asked what was possible for a certain tonnage).
While technically it wasn't allowed to exceed the old treaty until January 1937, the Admiralty pointed out that by designating them as replacements for the older carriers it would be allowed (just) to lay down two more of the Colussus class. In fact the Navy had no intention of letting go of the Glorious and Courageous at least, but they needed to get busy if they were to have any hope of meeting their needs in carriers. Accordingly it was agree to lay down two more ships in the Autumn, a supplementary budget having been approved. The Navy's arguments had been directly aided by the start of the Spanish Civil War, and the need to conduct neutrality patrols, a task for which the CVL were ideally suited, and that the Courageous and Glorious were already committed to them.
HMS Vengeance would be laid down in October 1936, to commission in December 1938
HMS Venerable would be laid down in December 1936 to commission in January 1939
The ordering of the new carriers could of course not be concealed (especially when the Anglo-German treaty required the RN to inform the Germans of their planes), and it was no real surprise (given, in any case, how deeply Admiralty intelligence was into the Germans building programs) when they learnt that Germany was laying down their first carrier in October 1936 (although they were interested to note it had been advanced a few months from its initial timescale). The design of the carrier they found interesting (although poor by their standards); it didn't seem to be armoured to anything like the extent of the RN fleet carriers (although it was nearly as big), and carried a heavy surface armament. It was estimated to be able to carry around 45-50 planes, assuming these would be similar size to current FAA planes, and the estimate was that this would probably be split evenly between fighter, dive bomber and torpedo bombers. The FAA started to consider which planes they would be; it was not clear whether the Germans would develop new planes purely for carrier use, or modify existing ones.
In view of this development an analysis of the other major naval powers was undertaken. The French, while aware of the improvements of British naval airpower, considered that at present their scope of commitments were covered by land based planes. They were considering a modern replacement for their aged aircraft carrier, but at present they had other projects with a higher priority for funding.
The USA had its own needs and a plan for meeting them. They had 2 large and very useful conversions, the Lexington and Saratoga, plus their first modern carrier the Ranger in operation. They had two more improved modern ships, Yorktown and Enterprise, well under construction, and another one, Wasp, would be laid down in April. That would give them 6 modern and powerful ships , each of which carried 80+ planes, which would give them a carrier strength greater than that currently under construction for the Royal Navy.
The Japanese were, as usual, keeping very quiet about exactly what they were up to, especially since they had announced their withdrawal from the naval treaties. It was known that they were extensively rebuilding Akagi, Kaga having already finished her reconstruction, in addition to the modern if small Ryujo. The larger Soryu, similar in size to the new American carriers, was expected to complete next year, and a sister ship the Hiryu was to lay down sometime this year. That would give them a similar strength to the Royal Navy.
The plans of the German navy had already been analysed; and some conclusions about the liely use of their first carriers discussed. While it would be possible to use one or two carriers to accompany a large scale raid by two or more fast capital ships into the Atlantic was possible, it was seen unlikely as any discovery would mean interception by superior RN forces, and the carriers would be isolated and would run out of planes. A much more likely scenario was the use of a carrier force to cover the escape into the North Atlantic of one or more raiders; this would allow the carriers to retreat once the aim had been accomplished, thus preserving the valuable ships. A third possibility was to cover operations in the southern part of the North Sea out of effective range of land based air.
Finally the Italian navy did not seem to have an aim of developing a carrier arm, probably due to the relatively easy availability of land based planes to support their operations in the Med. It was noted, however, that there seemed to be plans to improve the anti-ship capability of the RA.
The Admiralty used the points of the Japanese and American construction to press hard for an expanded construction program of their own; in particular they wanted 2 more Formidable class ships to order in early 1937 to give them rough parity in modern carriers. The treasury was sympathetic, but was being difficult in actually making the funding available.
