Ever since subsims have existed, we players have gotten used to obtaining vital info from 2d screens or icons. It has become second nature to check the little dials or numbers around the screen to see the condition of our sub.
Recently, playing with TDW's UI mod, I set the options so all icons disappear when not in use. It was a bit unnerving at first, but then I realized I could probably read much of the same info from the 3d dials around the boat. Sure enough:
1. Helmsman station - engine telegraph, ship heading, rudder angle:
2. planesman station - Depth meter, dive plane angle, engine RPM:
3. navigator station: clock with current game time:
You can also find repeater dials in the conning tower, sonar room and bridge. After a while it becomes second nature and much more immersive to obtain the info from the 3d world rather than from 2d icons.