Sending later designs back to prewar industries

Which later designs could help earlier navies without requiring impossible industrial changes?

Useful transfers depend on what the earlier industry can build: carriers, submarines, anti-aircraft guns and radar offer different national possibilities.

Malta and Midway carrier designs are suggested for Britain and the United States. A British submarine design also enters the discussion, but its identity is indistinct. An advanced German submarine could overwhelm an industry unready to build it. Japan is offered an automatic 3-inch anti-aircraft gun, while radar is suggested as a more buildable Italian benefit. Busy French yards constrain major additions, making a torpedo-boat design a more feasible option. The value of a later design depends on earlier manufacturing capacity.