The novel, based on the author's experience of serving in corvettes and frigates in the North Atlantic in the Second World War, gives a matter-of-fact but moving portrayal of ordinary men learning to fight and survive in a violent, exhausting battle against the elements and a ruthless enemy.

The crew cross the Atlantic many times on escort duty in all kinds of weather, often encountering fierce storms in one of the smallest ships built to protect Allied convoys.

The men endure the ship's constant rolling and pitching in the huge waves, freezing cold, the strain of maintaining station on the convoy on pitch-black nights and the fear that at any second a torpedo from a German U-boat could blow them to oblivion.

The Royal Navy is now finally gaining the upper hand over the U-boats and Saltash adds to the growing number of kills due to Ericson's determination and patience.

A few of them, prompted by determination or struck by guilt, scuttled or destroyed themselves, or ran for shelter, not knowing that there was none; but mostly they did what they had been told to do, mostly they hoisted their black surrender flags, and stayed where they were, and waited for orders.

Over half a century later, the historian Paul Kennedy still considered Monsarrat's fictionalisation of his experiences as the best and most authentic guide to the mentality of the wartime escort commander.

[2] The novel was made into the film The Cruel Sea in 1953, directed by Charles Frend and starring Jack Hawkins as Commander Ericson and Donald Sinden as Lockhart.

The cast included Donald Sinden (Narrator), Philip Madoc (Ericson), Paul Rhys (Lockhart), Michael Maloney (Ferraby), Helen Baxendale (Julie Hallam), Emma Cunniffe and Jack Davenport.