In later interviews, Robert Mitchum admitted that much of the script was made up as they went along.
John Farrow finished the film, but Howard Hughes brought in Richard Fleischer to add a few shots (Hughes himself co-wrote the ending with Fleischer). Fleischer ended up reshooting the entire film.
RKO had to lower the bottom of the pool on Stage 22 to get the Mexican police submerging to the level required by Howard Hughes.
The film lost $850,000, the amount spent on making the new ending sequences.
Nick Ferraro's yacht was built entirely on RKO's Stage 22 - at the time the largest sound stage in the world. Initially, only a bridge set was called for, but studio owner Howard Hughes wanted more fighting scenes and more of everything in the finale, so an entire ship set was built to satisfy his wishes.