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.
There was a tragedy during the shooting of this movie, during a relatively straightforward special effects scene of an explosion in a gun turret. After the first take, Sir David Lean (Noël Coward wasn't present) was dissatisfied. Chief Electrician Jock Dymore, keen to get the scene wrapped before lunch, climbed onto the set with a bottle full of the flashpowder used for the explosive effect. The containers they were using were still white-hot from the first take, and the resulting blast killed Dymore and seriously injured two others.
The entire royal family, including Queen Elizabeth II (Princess Elizabeth at the time), came to visit the set one day.