Stanley Baker fought for the part of Bennett, and actually replaced another actor who had originally been cast.

Dirk Bogarde claimed to have been offered a bit part in this film.

On boarding the castle class frigate, Ericson and Lockhart question whether there is actually a castle called 'Saltash Castle'. There is a castle in Saltash but it is more correctly called Trematon Castle.

The Compass Rose was played by ex-HMS Coreopsis. She was given the number K49 in the film which was the number of HMS Crocus (sometimes wrongly thought to have been used in the film). The real number of the Coreopsis was K32.

The film debut of Alec McCowen

When the film was made in 1952, no Flower Class corvettes remained in Royal Navy service. The ship used was therefore the Greek corvette Kriezis, brought to Britain for scrapping. She was already scrapped by the time the film premiered.