Sea Sore.

Monte is a hapless bumbler in love with a police sergeant's daughter, who says no to their marrying until Monte shows he can get a responsible job with a uniform. He gets one as a ship's orderly on a Dayliner, but tells his prospective father-in-law he's the Captain. They all show up on the ship, and Monte must keep the real Captain locked up, away from his fiancée and father.