As for an extra one or two carriers compared to OTL, getting pilots of them is again relatively easy, the IJNAF had i think about 4000 pilots in 1941, mostly for their shore based units. Have enough of them retrained to fill one or two extra carriers, sure, this might butterfly a handful of landbased fighter and bomber/attack units, but nothing impossible or improbable.
To clarify this part further as i was in a hurry few hours ago, probably this is a more convoluted way, since we know 3 basic facts, one, the japanese were rejecting a lot of potentially good candidates in their prewar training only keeping the very best, two, during the war however they found enough pilots to man their 50,000 plus combat aircraft they produced (just that they didn't had time and later in the war fuel to train them well), and three the requirements in fuel to train one extra airgroup are minuscule compared to total consumption in prewar years, obviously the simplest way is to just train the one extra carrier air group from scratch starting 1937 when our POD occurs, all else being equal.
About the extra BB and CV, the potential bottleneck would be machinery, there is not a lot of data about that part around, but again, there is a relatively simple way to get around that, just fit the two Hiryus with 104,000HP destroyer machinery like they did later in the war, and power the Shokaku and the 3 BBs with 160,000HP machinery (replacing the OTL 150,000HP Yamato machinery). Having couple of destroyers delayed won't be that big of a deal compared to the overall benefits of this ATL program being implemented.
PS: Oh and regarding getting these extra BB and CV, IF the above chart is accurate in this respect, to get the Hiryu CV yes you can replace Nisshin (and perhaps replace Junyo with the other Hiryu, a tight fit but they could probably just about have it ready for Pearl Harbour, if not shortly thereafter) while to get the extra 40-45,000 ton Yamato, since the slipway requirements for such a ship would not be as demanding as for the OTL Yamato, perhaps just some relatively straighforward deepening work for the docks where the OTL Shokaku or Zuikaku were built would be enough to get it laid down in 1938 there. Can also take the Mizuho out of this ATL building program to ease things up.
To clarify this part further as i was in a hurry few hours ago, probably this is a more convoluted way, since we know 3 basic facts, one, the japanese were rejecting a lot of potentially good candidates in their prewar training only keeping the very best, two, during the war however they found enough pilots to man their 50,000 plus combat aircraft they produced (just that they didn't had time and later in the war fuel to train them well), and three the requirements in fuel to train one extra airgroup are minuscule compared to total consumption in prewar years, obviously the simplest way is to just train the one extra carrier air group from scratch starting 1937 when our POD occurs, all else being equal.
About the extra BB and CV, the potential bottleneck would be machinery, there is not a lot of data about that part around, but again, there is a relatively simple way to get around that, just fit the two Hiryus with 104,000HP destroyer machinery like they did later in the war, and power the Shokaku and the 3 BBs with 160,000HP machinery (replacing the OTL 150,000HP Yamato machinery). Having couple of destroyers delayed won't be that big of a deal compared to the overall benefits of this ATL program being implemented.
PS: Oh and regarding getting these extra BB and CV, IF the above chart is accurate in this respect, to get the Hiryu CV yes you can replace Nisshin (and perhaps replace Junyo with the other Hiryu, a tight fit but they could probably just about have it ready for Pearl Harbour, if not shortly thereafter) while to get the extra 40-45,000 ton Yamato, since the slipway requirements for such a ship would not be as demanding as for the OTL Yamato, perhaps just some relatively straighforward deepening work for the docks where the OTL Shokaku or Zuikaku were built would be enough to get it laid down in 1938 there. Can also take the Mizuho out of this ATL building program to ease things up.
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