William Grefé wrote the story for this film prior to Les Dents de la mer (1975), but could not get anyone to finance it until after Les Dents de la mer (1975) was a huge hit at the box office.
According to numerous interviews with director William Grefé, star Richard Jaeckel only flubbed one single line of dialogue throughout the shooting of the whole film.
Henry Silva was originally approached to play the lead role, but had to turn the offer down because he did not know how to swim.
The Arriflex camera that was going to be used on the first day of shooting was accidentally destroyed, so director William Grefé had to make do with another camera of lesser quality. A boat that was also needed for use on the first day of shooting got stuck on a sandbar at low tide for approximately four hours. In addition, as if to add insult to injury, star Richard Jaeckel cut the back of his head and had to be sent to the hospital to get his head wound stitched up on the exact same day. Fortunately, Jaeckel insisted on still working, despite requiring stitches for the gash on his head.
William Grefé paid $300 for the van that Richard Jaeckel drives in the film. He subsequently sold the van after the film was finished.