All the scenes involving Eli Wallach's real-life wife Anne Jackson were cut from the theatrical release, but were restored for the expanded television version that included fifty-three minutes of previously unseen material.
Cameron Mitchell played the Captain of the "Goliath", but all of his scenes were deleted from the final cut.
One-Take Wonder: In the beginning of the movie, whilst Gail is diving, she reaches under a part of the shipwreck and gets her arm yanked by the giant green moray eel, which causes her to scream in pain. In real-life, Jacqueline Bisset's Stunt Double, Jackie Kilbride, dislocated her shoulder doing this scene. A diver was told to pull the stick attached to her wrist from inside the wreck. When the stick appeared, he pulled with all of his might (as instructed). The scene was done in one take, with multiple cameras, as there was no chance (or need) for repeating it.
No Stunt Double: Though Nick Nolte and Jacqueline Bisset, for authenticity, did many of the underwater scenes themselves, the more dangerous sequences were still performed by stunt doubles.
Romance on the Set: Reportedly, Jacqueline Bisset and Nick Nolte didn't get along well when the movie began, but ended up having a romantic relationship for most of the production schedule. This made producer Peter Guber very happy because he felt that the more chemistry the two leads had, the better the perilous dramatic scenes involving them would work in the movie.
Write Who You Know: Romer Treece was inspired by real-life treasure seeker diver Teddy Tucker, who helped Peter Benchley write the novel. Tucker was hired as a special consultant to the production, and appeared in the movie playing The Harbor Master.