Character mistake: About half-way into the movie the Captain asks for a fathometer reading and is told 150 fathoms. He preforms a mental calculation and says that it is 310 meters and over a thousand feet. In fact, 150 fathoms is 275 meters or 900 feet (1 fathom = 6 feet = 1.83 meters). (00:57:15 - 00:57:40)
Character mistake: When the U-Boat first appears on the U.S.S. Haynes' radar screen, operator Andrews turns his head to the screen a split-second before the blip actually appears. The swiftness of his reaction indicates that he is reacting to the radar signal, not that he has his face turned to the screen by chance; the actor simply made his move too early.
