How does a submarine stop?

Normally the hydrodynamic friction (movement through the water) is enough to slow down a boat as long as the screw is stopped. If we need to stop in a hurry we would ring up "all back emergency" on the engine order telegraph. That works quite well. I forgot to say that there are other reverse positions on the engine order telegraph: "all back 1/3," "all back 2/3" and "all back full" if my memory serves.