[REQ] Max possible depth indicator

[ygirouard]

Not sure if this would be possible, but it would be nice to know what is the max possible depth you could go to instead of just knowing the depth under keel at any given time. Having to calculate current depth + depth under keel to know how deep you can dive without crashing at the bottom is not always practical, especially in emergency situations.

I believe the navigators had maps which showed known depth to begin with (right?), but all we have in the game as far as I know (correct me if I'm wrong) are shaded areas that more or less indicate shallow waters versus deeper ones, but doesn't show any numbers on the depth there.

Maybe a new command could be added so the navigator could just print the max possible depth in the message box (not the limit of the sub, but the actual known depth at your location)?