That was a really nice one, i liked the feeling of having to slowly piece out how the submarine worked and how to get it back to the surface on your own. Through i havent really been able to get it out of the small alcove it appears to be stuck in at the start.
I was not able to reproduce it, but you are probally facing a wall (if you accelerate facing a wall you will hit it and make a hole on the sub). You can turn on the Main and GPS Circuit breakers and see on the map if you are close to the wall and use the direction controllers (left and right) to turn the sub