[Olefin]

2) At what point during WW2 did the US Navy overtake the Japanese Navy in the Pacific?

The US Navy was always larger than the Japanese Navy but was it was split between the Atlantic and Pacific oceans. The Japanese Navy was all in the Pacific. Would early 1943 be right?

Actually the US Navy in some ways was deficient to the IJN at the start of the war - the IJN actually had more carriers in commission - 6 fleet carriers and 4 light fleet carriers versus the US with 7 fleet carriers and 1 escort carrier - and they actually added several light and escort carriers early in the war and they basically were at parity with the USN in numbers of cruisers (but Japanese light cruisers were inferior to US ones in terms of guns and size)

Keep in mind that Japan and the Allies were actually very even at the start of the war as far as in terms of deployed ships in the Pacific but that Japan's initial victories gave them superiority in the Pacific which lasted until basically the end of the Guadalcanal battles - 1943 was where the US managed to rebuild their fleet, especially in carriers, to be able to take back the advantage in the Pacific by late 1943

The early battles gave them a big advantage sinking or disabling 9 battleships, one battlecruiser and basically destroying just about everything the Allies had in the Western Pacific. If they hadnt lost all four carriers at Midway it might have been mid 1943 before they lost naval superiority over the Allies.

As for the British Navy and when the US surpassed it - once the US really got going on building ships in 1943, along with the losses they had taken earlier in cruisers and destroyers, they were eclipsed by the USN. It was one reason that they conceded the Indian Ocean for so long to the Japanese - i.e. they literally didnt have the ships to risk there - not until after the Italians and Germans were out of the game.

Looking at Hitler's navy I dont think plan Z would have been the war winner - they certainly could have hurt the British more with the new ships - the real way they could have won was if Hitler had actually built a lot more submarines earlier and had been able to give the Kriegsmarine and effective naval arm. One of Goering's big mistakes - and he made a bunch - was not supporting the naval effort. Given more fighters to defend the subs and especially more patrol bombers and long range naval seaplanes even the force they had could have done a lot more damage to the RN. Add in the submarine numbers they had by early 1943 at the war start and the RN would have most likely lost.