Below (2002)

In the dark silence of the sea during World War II, the submarine U. S. S. Tiger Shark prowls on what should be a routine rescue mission.

But, for the shell-shocked crew, trapped together in the sub's narrow corridors and constricted spaces, this is about to become a journey into the sensory delusions, mental deceptions and runaway fear that lurk just below the surface of the ocean and deep inside the human psyche.