Depth to bottom?

[vodkajello]

In my continuing journey of learning the game I've done some pretty silly things. Some of them I've mentioned in other threads. (Systematic elimination of all non friendly targets, mostly neutrals...)

In my second patrol I dove too deep and hit the ocean floor. Not at high speed of angle of descent, so no biggy. I got a repair crew together and took care of it.

Is there somewhere that tells you how much distance you have to the bottom? Some kind of depth reading you can take? I'd like to avoid doing something like that in an emergency. I can just see myself ordering a crash dive to escape some planes and hiting the bottom at a 30 degree incline. ouch.