Thanks for the info. I kinda expected three commisioned officers as watch officers.
Didn't know about the two NCO's sharing a watch.
Also obersteuermann sounds like an officer to me and in the Gibraltar scene in the movie the kaleun takes only the obersteuermann with him to the bridge.
But I guess this would make sense in real life as he would probably be older and more experienced then the two watch officers. Well, it's all clear to me now.
Maybe I should watch the movie again.