Wrong movie:
After being cleared for all blame for a manoeuvre that cost him his submarine and the lives of 50 men, Commander Bolton (Allied) is given the command of a secret training mission based from Scotland. With a small group of men, he trains to operate several 3-man submarines that will be used to infiltrate German waters and ambush key boats within the German navy. However, men within the group blame him for the deaths and also are under a great deal of pressure with the tight training schedule.