backer,
do you think you could make your uboats spawn from an airbase, like the airplanes?
In the game, air support for the germans is enabled and working. You radio a message, and if you are within range from a base, aircrafts are spawned. If you could make with code injection or dll that an airbase spawns Ai uboats, then we just would need to add the airbases with uboats in the middle of the atlantic for the historical periods we want.