Even though her character is presented as an elderly, retired woman, Shelley Winters was only 51 years old when the film was made. Ernest Borgnine was actually three years older than Winters, despite the fact that his character treats hers like a old woman.
Shot in sequence, taking advantage of the fact that the principals became dirtier and more tattered and suffered injuries - some real and some artificial - as they progressed.
Stella Stevens said in a 2006 interview that when she first read the script, she could tell by the writing that whichever actress played the "fat lady" (Belle) in the movie would end up getting an Oscar nomination. And she was right. The role went to Shelley Winters, and she received an Academy Award nomination for Best Supporting Actress.
According to Ernest Borgnine and director Ronald Neame, Shelley Winters loved playing Gin Rummy. To keep her occupied during breaks in filming, Jack Albertson, who played her husband, would play Gin Rummy with her. According to Borgnine, Albertson ended up winning $260,000 from Winters. Both Borgnine and Neame said Albertson never got paid.
Paul Gallico was inspired to write his novel by a voyage he made on the Queen Mary. When he was having breakfast in the dining room, the liner was hit by a large wave, sending people and furniture crashing to the other side of the vessel. He was further inspired by a true incident which occurred aboard the Queen Mary during World War II. Packed with American troops bound for Europe, the ship was struck by a gargantuan freak wave in the North Atlantic. It was calculated that if the ship had rolled another five inches, she would have capsized like the Poseidon.