The steamboat used in this movie was originally built and used as the Cotton Blossom, in MGM's Show Boat (1951). It was also used in Raintree County (1957) and The Adventures of Huckleberry Finn (1960). In the 1970s, it was one of the props auctioned off by the studio.
Original title was "Company of Cowards", which was the name of the source novel, but the studio decided it was not marketable. Theme song "Company of Cowards" remained, however.
After their success in "The Courtship Of Eddie's Father", Glenn Ford specifically requested Stella Stevens for her role. She was under contract to Paramount at the time and loaned out to MGM. They went on to co-star in a third film, "Rage", at her new studio, Columbia, two years later.
As is already mentioned, Alan Hale Jr. got his role as The Skipper on "Gilligan's Island" because of this movie, having been spotted by Sherwood Schwartz at a restaurant in his Civil War uniform. It's also of note that Hale's fellow future "Gilligan's Island" cast member, Jim Backus, is also in this movie.
According to Glenn Ford's biography (written by his son), Glenn Ford and Stella Stevens had an affair during filming. He says she hurt his back.