Indiana Jones and the Raiders of the Lost Ark
Director: Steven Spielberg
This is the VHS release (see more).
The year is 1936, and the American and German governments are both seeking the Ark of the Covenant (Hitler believes it holds a mystical power which will render his armies indomitable). Dr. Indiana Jones, archeologist, is employed by the US to locate this treasure. After numerous narrow escapes and confrontations with the Nazis in a pursuit that spans several countries, Jones finally secures the Ark.
A U-boat plays a minor role in this film. A boarding party from the U-boat captures the Ark from a pirate ship. Jones swims to the U-boat, climbs on deck, and rides along to the Nazis' secret base in Greece.
NotesAs noted in the Internet Movie Database, the U-boat travels, surfaced, on a lengthy journey to a secret base with no lookouts posted. This unorthodox behavior allows Indiana to hitch a ride unnoticed. Some of the U-boat scenes were shot using the mock-up from Das Boot which was filming nearby.