hi darthlucky do you use the Commander mod also did you do the Academy training before started your Campaign to get 1500 renown for extra uboat upgrades if so make a new career with same kapitans name pick a same uboat and start date
also pick the same flotilla you used in the Mediterranean and all should be fine and full steam ahead sir
its just like getting a tow back to base you may be able to pick a new uboat also when you make a new career but keep your kapitans name the same