[SeaviewSkipper]

Yes, but it IS an issue that should be dealt with. Has it? It happened to me a couple of patrols ago. I was in a very shallow area and took some serious depth charge damage. My after torpedo room fully flooded and the engine room partially flooded. I crashed into the bottom stern-first. I didn't realize it at the time, but that caused my rudder to break-off. Somehow I survived and laid on the bottom until my crew repaired the bulkheads and pumps and expelled the water. I surfaced at night after many hours under, still not realizing I had no rudder. When I couldn't change course I knew there was serious trouble. I used the free camera to zoom into my stern and saw that the rudder was gone. End of patrol and end of sub.

I don't think damage as severe as a missing rudder should necessarily be repairable, because you'd have to send divers over the side and try to jury-rig something. I doubt it could be done successfully.
But I DO think you should have some options, like radioing for help from another sub or perhaps abandoning ship and going ashore somewhere. I sent a status report back to base and they acted as if nothing was wrong. Obviously the game programmers didn't include an option for the "lost rudder scenario".