Roberto Rossellini was removed as director the day before filming was due to start. Richard Burton then tried to quit the film, as the only reason he agreed to do it was to work with Rossellini, but was held to his contract.
Director Bob McNaught, working as the Associate Producer, replaced Roberto Rossellini as the director. A press release stated..."but Rossellini decided at almost the last minute that 'Sea Wife' was not his cup of minestrone." Not the first nor last time a director quit a movie, but one of the few instances where the production company used it as a publicity story.
The Japanese sailor on the submarine who acts as an interpreter was played by Kenji Takaki, not Tenji Takagi: Takaki also had a prominent part in A Town Like Alice (1956) as a Japanese soldier: he died in 1984.
Cy Grant (Number Four) and Richard Burton (Biscuit) served in the Royal Air Force as navigators in World War II.