Actually a fast noisy submarine at least in wartime is very quickly a DEAD submarine. You want 1 of the very quiet slow "hole in the ocean" types; currently the Germans have the edge with their all electric boats pared with the "silent" launch torpedoes that get about 2 miles away from the launching sub at slow speed then race in to detonate below it`s target at 50+ knots. The greatest danger to themselves is getting hit by other subs that cannot detect them even a very close ranges...