+1 but would never happen in aces high, it would have to be redone to allow Subs to have a chance to attack the carrier, you can't use PT Spawns because while PT boats do 50 knots even the XXI boat wouldn't get there in time if not take a good hour or two to do so.
With the horde mentality of the gameplay, Subs just would be a wasted resource for now. We have no convoys, no merchant ships - only a fast carrier group.