The film's technical achievements are central to its narrative impact:
The film is frequently cited as a masterpiece of sound design, using surround sound to simulate the claustrophobic and terrifying environment of a submarine under depth-charge attack.
The American crew's objective is clear: board the disabled U-boat, overpower its crew, and seize the Enigma cipher machine along with its codebooks. This device would allow the Allies to intercept and decode German naval communications, neutralizing the deadly "Wolfpack" submarine threat.