ORIGINAL: Feinder
I'm obviously not understanding the Japanese production system here, so bear with me (in my one Japan game, I just left everything alone).
But if Japan has such an over-abundance of aircraft production, is it actually short on ship production?
Yes, starting on GT one, if you do nothing (no cancellations, no accelerations), you are spending more naval shipbuilding points than you are earning. What happens is that Yamato will start to slip (she will not advance every day due to insufficient points). If you halt one of the point hogs (Yamato, Musashi, or Shinano), not only do you fix the problem, you now have enough points available to do some accelerations. The whole IJ shipbuilding program is give here, take there.
You can also expand some shipyards, or convert merchant shipyards to naval. This has the usual problems of costing supply and taking time. But if you expand and convert a number of smaller yards instead of one or two large ones, the added capacity can come on line pretty quickly (probably too quickly for realism).
Considering from a previous comment, it sounded like you could get the Unryus too early for them even have replacement planes (that seems silly, and sounds -way- too early). But if you can get CVs so early there aren't replacement AC for them, it seems that why would you want to STOP any of the ships?
-F-
See above. There aren't enough points to do everything. Accelerating ships, especially ships that are within 10*durability in days of arrival, is expensive. You can't have everything. Subs in particular are extremely expensive to build even without accelerating.
He probably wants to get his posting number higher and earn a sixth star.
A good solution to this problem is to click the green dot [;)]
Maybe someone a bit more sapient than myself could tell me whether the ability to accelerate shipbuilding as portrayed in WitP has any foundation in reality?
I think that acceleration per se is not necessarily unrealistic, but it is way to easy to expand shipyards. Too fast and too cheap.