Why giant Japanese battleships were limited by machinery and turrets

Could Japan have built Iowa-sized or larger monster battleships in useful numbers?

Hull construction was possible in limited yards, but engine and turret capacity would sharply constrain the programme.

An American interpretation of a Japanese monster battleship raises more than a question of hull size. Japan had limited facilities for building very large hulls, but the more decisive limits were engines and heavy turrets. Enlarging a design does not automatically create additional plants, machining capacity, gun production, or skilled labour for those systems. The same bottlenecks help explain the number and form of the capital ships Japan did build. Spectacular drawings still depend on an industrial chain capable of turning them into operational ships.