thumb|upright=1.3|The cramped, equipment-filled set of a submarine film ([[Das Boot, 1981)]]
The submarine film is a subgenre of war film in which most of the plot revolves around a submarine below the ocean's surface. Films of this subgenre typically focus on a small but determined crew of submariners battling against enemy submarines or submarine-hunter ships, or against other problems ranging from disputes amongst the crew, threats of mutiny, life-threatening mechanical breakdowns, or the daily difficulties of living on a submarine.
The genre plays on the psychological tension of the submarine's crew and their unseen enemy, signified by a soundscape that may feature explosions, the ping of sonar, the creaking of the submarine's hull under extreme pressure, the alarm ordering the submarine to dive, and the threatening sound signatures of a destroyer's propeller or of an approaching torpedo.
Some 150 films have been made in the submarine genre between 1910 and 2010, variously depicting submarines in relatively realistic stories about World War I, World War II or the Cold War, or purely fictional and fantastic scenarios.
Characteristics
Submarine films have their own particular semantics and syntax, creating a film genre concerned specifically with submarine warfare. A distinctive element in this genre is the soundtrack, which attempts to bring home the emotional and dramatic nature of conflict under the sea. For example, in the 1981 Das Boot, the sound design works together with the hours-long film format to depict lengthy pursuit with depth charges, and as the critic Linda Maria Koldau writes,