- Alan Smithee: After Richard Lester had the screenplay substantially rewritten by an uncredited Alan Plater, the original screenwriter asked to have his name taken off it, and the on-screen credit is given to the pseudonymous "Richard De Koker".
- Enforced Method Acting: The film was shot on an ocean liner in the North Sea. To get enough extras to convincingly portray a ship full of people, the production company ran advertisements in British papers, offering a lengthy cruise in the North Sea for free, but with the caveat that the ship would actually seek out the worst possible weather.
- What Could Have Been: Christopher Lee, John Mills and Donald Pleasence were offered the role of Buckland.
Trivia / Juggernaut