Continuity mistake: In a scene supposed to be after the ship has been fitted with radar, it is shown entering harbour with the 'lantern' removed and the aerial covered, which is how it's shown before the ship has the radar fitted.
The Cruel Sea (1953)
1 continuity mistake - chronological order
Directed by: Charles Frend
Starring: Denholm Elliott, Jack Hawkins, Donald Sinden, John Stratton
Other mistake: Just after the Royal Navy destroyer has sailed through and depth charged the area where the British survivors are, there is a shot of the churned up sea with sombre music playing, and the seagulls are flying backwards.
Tallow: If anyone else makes a noise, I'll have his guts for a necktie.