Character mistake: The crew many times refers to the sub as a ship - subs are always called a boat.
Ice Station Zebra (1968)
1 character mistake
Directed by: John Sturges
Starring: Ernest Borgnine, Rock Hudson, Patrick McGoohan, Jim Brown
Factual error: "Ice Station Zebra" is one of dozens of films which make the mistake of showing people carrying rifles such as M-16s with the magazines inserted. In the scene where Marine Captain Jim Brown arrives at the submarine via helicopter, he comes aboard passing his M-16 through a hatch with the magazine inserted, barrel first - a double safety violation. I first saw the movie in a Marine Corps base theater, and all of us yelled at the screen when we saw that.
Cmdr. Ferraday: We operate on a first-name basis. My first name is Captain.
Trivia: The submarine used in the movie as a (supposed) nuclear submarine was the U.S.S. Ronquil (SS-396), a WWII Balao-class diesel-electric submarine that had received a GUPPY IIA conversion. The number painted on the sail (509) was selected because it was from a block of hull numbers canceled at the end of WWII and never used.