**Sighs**. Tell me, do you enjoy been a rude dick? Also you
@dBSPL
The problem with narrow shallow waters v deep ocean isn't that the submarine can dive to near the bottom they can't.
But:
Conversely operating in deep ocean waters has its own challenges which are different. A submarine operating in shallow water at a certain noise level and depth may well be undetectable. The same noise level and depth in deep ocean water might as well shout "here I am".
A submarine designed to operate in narrow waters can afford to an extent to ignore its own noise. But one operating in deeper, oceanic waters need to be very careful. For instance anything above 6-7 knots creates
cavitation noises. In narrow waters thats not so much of an issue, it gets lost in the background and bounces off the seabed. In deep, oceanic water it can be heard for hundreds of miles.