After about three weeks of shooting, Noël Coward realized that (a) Sir David Lean knew a lot more about filmmaking than he did, and (b) he didn't care much for the long hours. So Coward effectively handed the directorial reins over to his partner at that point.
There were doubts as to whether Noël Coward could convincingly portray a hardened Naval Commander. After the movie's release, his performance was widely praised.
The entire royal family, including Queen Elizabeth II (Princess Elizabeth at the time), came to visit the set one day.
Noël Coward was a friend of Lord Louis Mountbatten, who was Captain of the Royal Navy destroyer H.M.S. Kelly from the outbreak of World War II until the Kelly was sunk by enemy action in May 1941. Coward wrote the screenplay for this movie based on Mountbatten's experiences on H.M.S. Kelly. Coward's character in this movie, Captain E.V. Kinross R.N./Captain "D", was also based on Mountbatten's experiences.