From the Mosquito thread I am trying to come up with a believable scenario that would give the UK a class of affordable big deck carriers instead of the Implacables and possibly Indomitable. I understand the logic of the Armoured Fleet Carriers, the assumption they would be hit and that there was no way the number and type of fighter aircraft available to the RN would be able to defend the carriers (or fleet for that matter) from the sort of intense land based air attack they expected to encounter and that these ships were designed as, treaty compliant, strike carriers able to weather air attack. The issue as I understand it was the experts calculated that fighters could never be scrambled fast enough to defend the ships given the expected warning times, therefore the ships would have to rely on their, guns, manoeuvrability and armour.
The issue is the first four were laid down in 1937 and the final pair in 1939 before being suspended in 1940 and how to either get the Implacables completed (maybe laid down in 37 or 38 with the first four) much earlier to a modified Indomitable design with higher hangers (two at 16' instead of one 14' and one 16' or both 14'), completed as Indomitables, or cancelled. The idea is the Implacables not compete for resources with escorts (as well as the final pair of KGVs) and a larger, non 2nd London Treaty compliment, design could be ordered in 1940 instead, perhaps also instead of the 1942 Light Fleet Carriers. The RN would then have the same four carriers completed before the end of 1941 with the possibility of an additional two in service by mid 1942. More importantly, a new design, capable of operating larger numbers of larger aircraft could then have been available by mid 1944.
Design pressures on the British carriers were the 22,000 ton treaty limit, the folded height of their biplane strike (torpedo) bombers, Swordfish at just under 14', the folded height of their amphibian aircraft, Walrus at just under 16' and the length, folded width and weight of either. The non folding wings of the Sea Hurricanes and initial Seafires saw the Implacables modified during build with wider forward aircraft lifts, while the deletion of the requirement to hanger Walrus or Otter amphibians was one of the justifications for the 14' hanger height accepted on the Implacables, though stupidly the Albacore was 14'2" and the Barracuda 15'2" so one wonders what strike aircraft the admiralty expected them to operate.
I'm going to throw in a new design pressure, the carriers of the Home and Mediterranean Fleets were expected to operate within range of higher performance land based bombers, therefore it follows that their strike aircraft would be operating within range of land based heavy fighters and as such would need to be of significantly higher performance themselves to have any hope of surviving to do their job. This would make the Fairy Battle / Hawker Henley the absolute minimum starting point for a torpedo, let alone dive bomber, but more likely the Bristol Blenheim or Beaufort. So my new design pressure is the new carriers and possibly part or even the entire Illustrious class, it having been determined that scrambling interceptors will be ineffective, therefore not worth carrying and that existing and planned TSR (Swordfish/Albacore), dive bomber/fighter and turret fighters designs will be so outmatched that it is doubtful they could push home a strike, that the decision is made to design the carriers from the start to operate large, powerfully armed, long ranged, high performance twin engined fighter and torpedo bombers, i.e. the Beaufighter.
Designed to operate a Blenheim sized, folding wing, heavy fighter and torpedo bomber would required 45'x30' 20-25000lb elevators, arrestor gear and barriers designed to stop 15-20000lb aircraft and catapults for 20-25000lb aircraft. Above all hanger height would need to be greater as twin engines would likely force the use of vertically folding wings, this alone could force the adoption of a 17' or greater hanger height. This would actually be true to the RNs doctrine at the time of regarding the carriers as a strike platform with Beaufighters and perhaps Blenheims or Beauforts instead of Skuas, Fulmars and Swordfish.