Darren Aronofsky (who wrote and directed Requiem for a Dream) could probably make the Sahara feel claustrophobic, and this psychological thriller about a haunted submarine, which he scripted with Lucas Sussman, benefits from his sure sense of characters imploding under pressure. Bruce Greenwood (President Kennedy in Thirteen Days) plays a naval lieutenant commanding a U.S. sub in August 1943; after he and his crew rescue three survivors from a British hospital ship that's been sunk, a German U-boat forces him to submerge, and in the depths of the Atlantic unexplained phenomena begin to drive everyone batty. Director David Twohy (Pitch Black), who also contributed to the screenplay, handles the combat suspense sequences masterfully, as the Germans probe the waters with sonar, drop a depth charge that rolls tortuously across the deck of the sub, and rake the masts with giant hooks. Like its cramped setting, the movie has more characters and conflicts than it can accommodate (including a British nurse, played by Olivia Williams, who finds herself trapped undersea with about two dozen horny sailors), but until the ghost story takes over this is a tense and absorbing war picture. 105 min.