I'm not sure if this was a bug in the game but after attacking a convoy somewhere off Iceland I was depth charged and seriously damaged.
Both my electric engines were destroyed, one diesel engine damaged beyond repair, my compressor was kaputt and both my rudders where destroyed. To make matters worse I had serious flooding in various compartments. I was sinking like a brick. Depth under keep was about 299 meters and I ended up landing on the ocean floor. By then the flooding was under control.I figured I would wait until the enemy convoy was gone and then surface. I rigged the boat for silent running and waited.
Once the enemy was gone I tried surfacing. No effect. Blowing the ballast? Also no effect. Both electric engines were kaputt which meant no underwater propulsion for me. I guess with my compressor destroyed I was to be stuck on the ocean floor until I ran out of air. What a horrible way to die.
But yeah, stuck at 299 meters and still in one piece...