Well, I did it. It sorta works. My first captain got transfered to training after 10 missions and a new captain arrived.
U-18 was U-19 for the first mission and all the sailors decided to play a trick on the new captain and tell him fake names but other than and an experience problem everything was okay (you can't update your crew until after the first mission).
My first mission was awful but I'll chaulk it up to a captain and crew getting to know each other.
Second mission (after the changes) was a lot better.