Don't worry, we all do things like that occasionally.
The USN would, in this rather implausible scenario, be potentially heavily outnumbered by the RN, IJN, MN and KM at the war's outbreak. I say potentially because there would almost certainly be a period of tension leading up to the conflict. Which nations started its rearmament program first would have an advantage.
But I doubt the US can outbuild these four nations combined efforts even with the distraction of an Eastern Front for Germany and maybe Japan.
Now there are some people who will immediately poo-poo this as completely impossible, and come up with some sort of statement about how Britain can never possibly afford it, but if the Royal Navy is able to maintain its
Pre-War Construction rate, which should be noted was perfectly feasible on a
Peacetime Budget, it may still be larger than the USN in 1944!.
In the 1936/37 Construction Program the Royal Navy Laid Down NINE Capital Ships, and there is actually spare capacity left over, if only because several Shipyards still had a considerable number of civilian contracts to complete, for example John Brown was occupied with RMS Queen Elizabeth. There are in fact at least Twelve Slipways capable of Capital Ship Construction in the UK:
John Brown, Clydebank (2), Harland and Wolff, Belfast (2), Vickers-Armstrong, Tyneside (2), Vickers-Armstrong, Barrow (2), Swan Hunter, Tyneside, Cammell Laird, Birkenhead, Fairfield, Govan (2).
The Capacity to repeat the number of hulls laid down in the 38/39, 40/41 and 42/43 Construction Programs does exist. It didn't happen OTL due to the outbreak of WW2 in 1939, however, ITTL the Royal Navy gains an extra Two Years of preparation time where there are not the same historical delays due to losses and disruption and no one is bombing anyone. There is simply more time and resources, two years of not even having to convoy your shipping will do wonders for the economy and industry (10-20% of capacity is lost simply by this). The world's two busiest Trade Routes, and the significance of this cannot be overstated, the English Channel and the Suez Canal, will remain open so more capacity can be directed to Naval Shipbuilding.
As an example of this, after the Belfast Blitz Harland and Wolff had to shut down altogether for six months, ITTL that simply isn't going to happen. There is frequent speculation that
HMS Prince of Wales was lost so dramatically due to it being bombed when fitting out, again which ITTL isn't going to happen.
In the absence of being bombed Supermarine will not have to relocate its R&D department from Woolston,
years of work were lost. Little things like Harold Payn being able to remain as Chief Designer at Supermarine, he was considered a security risk as his wife was German, mean that Joe Smith, no that really was Supermarine's Chief Draughtsman, can remain focused on the Spitfire. Which means that with greater production capacity and a design team with more time and fewer distractions can produce a Seafire in 1940. Built using the construction which is not lost when the Luftwaffe now hasn't bombed Woolston. Which means that Fairey can possibly get the Barracuda which first flew in 1940, with more time and resources in service by 1941, and while its not especially impressive by 1945 standards, it is competitive compared to the Dauntless and Devastator. Its a long list, the Butterflies can only grow. (The OTL 1942/43 Construction Program contained 28 purpose built Carriers.)
In This Time Line completing the 36/37 Program will more than likely be functionally on schedule. The 38/39 Program will be the 4
Lions that were ordered and possibly 5 Carriers instead of 2, and the 40/41 Program perhaps 1 Battleship,
Vanguard, and 8 Fleet Carriers. There is a practical limit to the number of Battleships that can be built due to the shortage of Gun-Pits. Exactly what sort of Aircraft Carriers will be built is a matter of speculation. The POD is too late to substantially change the
Illustrious Class, although it might be possible to re-work them into something comparable to the
Implacables. Given the time available and increased resources the DNC and the Third Sea Lord might well rethink their priorities and move to constructing a series of Improved
Ark Royals, something like a very British
Shokaku?
The construction of the Light Fleet Carriers will almost certainly begin earlier, and as the builder of the First Escort Carrier Britain knows how, ITTL
Jervis Bay and
Rawalpindi might well end up as such. The RN did consider more conversions of such small Liners, Britain requisitioned over 60 AMCs in 1939.
By 1944 13 Fast Battleships and 18 Fleet Carriers are possible. (With perhaps as many Light, and as many Escort as can be converted, just the 17 AMC's now not lost to the Kreigsmarine by 1941 are available)