Trivia

Production had to be closed down several times due to Gary Cooper's frequent illnesses. This was Cooper's penultimate movie. He was diagnosed with advanced metastatic prostate cancer the following year.

Charlton Heston was impressed that Gary Cooper still performed his own stunts, including remaining submerged for long periods of time, despite his age and obvious ill health.

Although Charlton Heston was already a major star, he did not mind taking second billing as Gary Cooper was his childhood hero.

Charlton Heston said in his published book, The Actor's Life: ..."it was Cooper's film. After having borne witness all my movie-going life to the enormous presence he brought to the screen, I should've been able to figure that out. I was lucky to be in it. The experience of working with him and the friendship it created is one of the most valuable I've had in film. He was a lovely gentleman (that sadly outmoded word) and a total professional. There aren't many like him."

The sequence that immediately kicks the movie into high gear is Charlton Heston climbing the rope to the Mary Deare. He described that shot in his diary: "All my practice rope-climbing in the Paramount gym didn't mean a damn thing when I had to do the shot today, climbing from the deck of the tug in the big tank at MGM, up to the deck of the Mary Deare. What with the wind, spray, wet rope, and the rolling ship, it was a hell of a lot different from the gym. I popped a ligament or something on the first take and barely made it the last 10 feet up and over the rail."