At the part where the crew are on their way to meet the disabled U boat, and they are eating dinner, the black cook comes in and Captain Dahlgren calls him by his real name. The actor's name is T.C. Carson and the Captain says "I wish you were too Carson." His character's name is Eddie Green, so he should have said "I wish you were too Green," It's pretty small but I noticed it. If you watch you will notice the other actors at the table snickering at the mistake, but they continue shooting anyway.