The reason for the Centaur-class was the ever-growing size and weight of carrier aircraft. Once you start planning for airwings of Spearfish and Wyverns for a 1946-47 campaign against Japan the Colossus-class were too small. And those Specs didn't materialise until about 1943 so that is why the 1943 Light Fleet happened when it did.
They also had higher-power machinery so they had the speed to keep up with the true fleet carriers and were intended to receive more powerful AA batteries with 4.5in guns etc. plus the addition of some armour.
The 1942 Light Fleet was always intended as a cheap and cheerful way to get more carrier decks for the least drain on shipbuilding resources and quick build times.
Personally I feel that the Admiralty was overzealous in its ordering of the Majestics and perhaps the last 6 of the 1942 order should have been cancelled. The gap between them and the 1943 Light Fleet of 12 months would have been seen as a potential problem but it would have been known the last 6 ships would not complete until 1946-47 anyway. Whether you could bump up the lay down dates for the Centaur-class by 6 months would probably depend on slipway availability and the pressures of work on the DNC's staff to complete the design in time.
Most of the wartime carrier programme came too late to be of much use - build times were just too long. The only fleet carrier completed during the timespan of the war was HMS Indefatigable (laid down 3 November 1939).
Only 6 Colossus were completed before the war ended despite laying down in 1942-43 (HMS Ocean just pips in at 8 August 1945).
In the dark days of 41-43 it might have looked like the Eagles and Colossi had a potential war-ending role (even the USN's own Essex and CVL programmes were still ramping up) but in reality it proved not to be. Maltas and Centaurs were never going to be anything but post-war replacements in reality. In fact you could argue the same for the cruiser programme of Bellerophons, Neptunes and N2s; they were all actually quite pointless for wartime needs as they could never be completed for anything but a post-war RN.
So there is perhaps a case that in early 1944 a long hard look should have been given to the 1944 and 1945 Programmes and a more realistic view taken of the size of those programmes given how much of them ended up as scrap or quickly sold off as surplus. The same could equally be said of the USN build programme post 1944.
Implacable class
The delays in their completion were largely before they were launched. Indefatigable suffered a period of suspension in 1940. Fairfields had an insufficiently large workforce to allow Implacable to be progressed for about 10 months in 1940/41. In both yards repairs were prioritised over new build in 1940/41 and destroyers were prioritised over the carriers in 1941/42. John Brown were told to prioritise the build of the monitor Roberts (ordered March 1940, laid down April, launched Feb 1941) over that of Indefatigable in 1940/41 which was building on the next slip between the launch of DoY and laying down of Vanguard. And then we had the design changes that were made to the ships in the light of war experience which, when you study the design, included many changes to the forward hull to accomadate the wider lift.
Im really not sure how much of that, if any could really have been avoided given the pressures on the shipbuilding industry as a whole in wartime Britain.
1942 Colossus / Majestic class
The 1942 Colossus/Majestic classes need to be viewed in the context of the time of the development of the design. That was late 1941/early 1942 especially following all the disasters that had befallen the RN off Norway in 1940, in the Med off Crete in May 1941 and the Force Z debacle in Dec. The need was for carriers to defend the fleet and to get them quickly so building smaller was essential. Hence the use of a machinery design that was already available. Also their size meant they would occupy slipways that could otherwise accomodate cruisers. So we see 5 planned light cruisers not ordered / cancelled in Aug-Nov 1942 just as the Colossus/Majestic class are ordered (see below).
The initial plans for the 1942 Programme in mid-Feb 1942 included 3 Colossus class ships. A month or so later a fourth ship was planned, to be built at Vickers Tyne in place of the battleship Lion but to be ordered later in the year.
Between Dec 1941 and April 1942 the Admiralty Plans Div were reassessing the numbers of carriers that the fleet was likely to need. And as it did so the carrier numbers kept increasing. By the end of April 1942 they wanted another 6 light fleets. (So we are now at a requirement for 10). Demands rose again and by Aug 1942 it was decided to order 9 extra ships (so taking the plan to orders for 13).
And that batch of extra orders results in the cancellation of 5 cruisers that had been in the initial Programme. That generates the capacity to construct the machinery for 10 light fleets.
By this time the carrier requirement at
Jan 1944 was seen as 16 fleet of which only 4 would be available (plus the old Argus, Furious & Eagle which were all worn out) with the two Implacables about to complete / building. And 1 fleet carrier = 2 light fleets. Against that background it was decided to order another 3 light fleets. So we get to the eventual total of 16 light fleets.
So at that point, late 1942, the Admiralty have the prospect of 6 fleet (Illustrious/Implacables) plus the 1940 improved Implacable (Irresistible reordered as the Audacious class Ark Royal) plus 2 Audacious (1942 Programme Audacious and Eagle) and 16 1942 Programme light fleets (equivalent to 8 fleet carriers). A grand total of 17 fleet carrier equivalents vs the perceived requirement for 16. At that point all the light fleets are expected to be in service by the end of 1945 with the first pair of Audacious class by March 1946. So the RN would finally have met its target not by early 1944 but by March 1946. That is still in time for the then estimated end of the Pacific war.
Order dates
14/3/42 - 3 ships Colossus, Edgar (later Perseus) and Glory
7/8/42 - 10 ships
16/10/42 - 2 ships Magnificent & Powerful at Harland & Wolff Belfast
7/12/42 - 1 ship Terrible at Devonport
These are then laid down between 1 June 1942 and Nov 1943 (8 in 1942 and 8 in 1943). Only 3 of these are after the order for the Hermes class were issued in July 1943 (see below).
There were delays in building these Colossus light fleet carriers due to changing priotities after they were laid down. So VA Tyne, Harland & Wolff, Hawthorn Leslie, Stephens, Fairfield & VA Barrow all received orders for LST(3) between Dec 1943 and Feb 1944 while they all still had light carriers in the yards and sometimes even on the slips. These had a high priority as they were needed for the 1945 far east campaigns and it was clear that the US was not willing to supply RN needs. That was not forseen until late 1943. The various yards also faced competing priorities for destroyers and submarines.
In terms of the actual completion dates, it is true that only 5 completed as carriers plus 1 as an aircraft maintenance ship before the end of the war, but even in March 1945 the Admiralty was expecting another 5 carriers and the remaining 1 aircraft maintenance ship by the end of the year with the remaining 4 carriers by June 1946. Having looked at the build times of the earlier ships and comments about the state of completion of the later ships in Aug 1945 then it is conceivable that, with one exception, completion dates would have slipped only another couple of months from that estimate. But even that one ship, Hercules at VA Tyne, should have been able to be completed by the end of 1946. The big issue is the postwar slowdown in the yards. The 5 wartime completed carriers took an average of 29 months from lay down to completion (26-33 months). The next 3 (Theseus, Warrior & Triumph) averaged 39 months (37-39 months). 7 of the 10 average months extra was after the hulls were launched and some 6 months of that for each ship was after March 1945, the last time I have data. For example, the RCN were planning to have both Warrior and Magnificent completed by the end of the year so that they could be in the Pacific in the first half of 1946. When you see photos of Magnificent lying at Harland and Wolff Belfast in 1946/47 she doesn't seem that far away from completion when laid up. 7 of the 8 squadrons for the air groups for the next 4 completions had formed between 1 Feb and 1 Aug 1945. The RN policy had been for this to happen only a few months (usually 3-6 months) before the parent carrier was due to be ready.
The two aircraft maintenance ships make an interesting comparison. The decision to convert them was not taken until around Dec 1943 while both were still on the slips. Pioneer completed first despite having been laid down 6 months later. Her build time was 26 months. Perseus took 41 months. Most of the extra time was after she was launched. There are reports that VA Tyne had a particular shortage of electrians in 1944, something that affected other yards from time to time in wartime Britain.
In terms of their reaching the combat zone, their work up in the Med in 1945 was extended, much to the frustration of their aircrews, by the lack of a sufficiently large Fleet Train with the British Pacific Fleet to support them in Pacific operations. Ultimately plans would have seen the first 3 (maybe 4) undertake operations in the South China Sea starting late Aug 1945. That deficiency probably added 3-4 months to their work up time.
1943 Light Fleet Carrier (Hermes Class)
The limits for the new generation of aircraft weren't produced until the end of 1942 at which point it became clear that a new light carrier design would be required to accomodate them. If ordered mid-1943 it was hoped they could be laid down between Dec 1943 and Sept 1944 for completion in 1946. The Admiralty Staff Requirement for them was dated 2 April 1943 and the first sketch design 29 May 1943. The initial design was for an 18,000 ton ship, based around a half set of Audacious machinery able to carry 18 TBR and 6 FF or 24 FF. The next generation of aircraft included the 1943 Fairey Spearfish. Then the modifications began. A design was not finally approved until Feb 1944 but I don't know exactly what form it took relative to the May 1943 sketch. So the 8 orders placed in July/Aug 1943 were no more than placeholders in the yards. That design was further modified in 1947 before work recommenced on the ships after their postwar suspension.
And the same competing priorities were still there in 1943/44 as in 1942. At VA Barrow the choice was a 1943 light fleet or more submarines for example.
The 1943 light carriers proved controversial from the start. Almost immediately there emerged an argument between the politicians, in the form of the First Lord, and the sailors, in the form of the Sea Lords. Were they ships for this war or peacetime? The compromise was to build 4 and postpone the others meantime.
By Jan 1944 4 were scheduled to proceed and it was hoped to start another ship in each of Q1 & Q2 of 1945 with the last pair (Monmouth and Polyphemus at Fairfield and Devonport) postponed until they did not interfere with other production. Even in March 1944 just as the first, Albion at Swan Hunter, was being laid down her completion date was predicted to be Aug 1946 with the rest following in 1947. And of course completion dates continued to slip to the right. So by then they really do become post war / peacetime ships.
And then you have capacity problems in the yards again. Monmouth at Fairfield had been one of the ships initially chosen to proceed back in 1943. But in the end, in early 1945, she was replaced by Bulwark at H&W which was laid down about a year after the other 3 that eventually were built. But she was laid down (in May 1945) on the same slip as Powerful was launched from (in Feb) with an LST occupying part of the slip until Sept. Could that have been forseen in mid-1943 allowing Bulwark to be laid down in Nov 1943 instead of Powerful? The 1943 light fleet carrier design was not sufficiently advanced at that point to allow that to happen.
Centaur, also at Harland & Wolff, was laid down (30/5/44) 10 days after the launch of Warrior (laid down 19/12/42) from the same slip. So again impossible to bring forward.
Conclusion
Proceeding with the 16 (reduced to 14) 1942 light fleet carriers was a sound decision at the time it was made based on good research. But no one could predict the shifting priorities and shortages in the yards and elsewhere in wartime that would delay service entry.
Could the design process behind the 1943 carrier been compressed? 10 monhs from Staff Requirement to approved design. The 1942 light fleet carrier took about 12 months from revised proposals being sent to the DNC for a hybrid carrier in Jan 1941 to the finalisation of a pure light fleet carrier in Feb 1942. Maybe a few months but I doubt it would be enough to allow them to enter service even in the first half of 1946.
