battery recharge question:historic

[Task Force]

Originally Posted by brett25

I noticed in SH3 that I am able to recharge the battery without moving the sub, as long as the engines are running and im in recharge mode. Does anyone know if this is historically correct? Did the uboats have a gear that disabled the propeller shaft allowing the engine to stiull spin the shaft to recharge the batteries withput having to be in motion?

I belive when U boats are rechargeing they use one engine to spin one prop and the other to recharge. so, i believe if the were stopped, they would have 1 engine rechagreing and running and the other stopped.