Casting Although the role of the cowardly officer Bennett was an Australian in the book, the Englishman Donald Sinden was originally
screen-tested for the part and the Welshman Stanley Baker was screen-tested for the part of Lockhart. At Jack Hawkins's suggestion and after further screen-tests, the roles were swapped. Future director
Don Sharp had a small role.
Virginia McKenna launched her career with her small role and met her first husband,
Denholm Elliott, on the set.
Filming The film was shot on location in
Plymouth Naval Dockyard and the
English Channel. Scenes showing the sailors in the water were shot in the open-air water-tank at
Denham Studios. Other work was completed at Ealing studios. The brief scenes showing Petty Officer Tallow coming home on leave were filmed in Stepney, London. The crane jibs above the houses in the background were edited in as the docks were over a mile away. Donald Sinden (playing Lockhart) suffered in real life from
negative buoyancy, meaning that he was unable to float or swim in water, which was discovered while filming the sequence when the ship
Compass Rose is sinking. Co-star Jack Hawkins (playing Ericson) saved him from drowning in Denham's open-air water-tank. In a scene where the corvette’s main 4 inch gun was to be fired at night, the first round used was a simple pyrotechnic load which resulted in a large wad of burning cotton falling unspectacularly out of the gun’s muzzle. As a consequence, and unbeknown to Donald Sinden, who was acting as the officer in charge of the gun, the crew decided to load a live 4 inch round for the second take. Sinden sighted a small light “bobbing on the water” through his binoculars as he gave the command to fire, and this turned out to be a small fishing boat. The live shell missed the boat by an estimated “2 to 3 yards” according to Sinden, narrowly averting disaster.
Editing The most traumatic scene in the film occurs after a submarine has caused havoc to the convoy and the ASDIC (sonar detector) reveals that it is beneath a group of British sailors who are struggling in the water, hoping to be rescued. Ericson, faced with an appalling choice, drops the depth charges that will destroy the enemy but will also kill his countrymen. Yet for all his professionalism he is a human being and he later gets paralytically drunk and bares his feelings to Lockhart. Jack Hawkins, personally moved by the situation, delivered a fitting emotional performance and at the end of the scene tears were rolling down his face. Two days later, after seeing it cut together, Michael Balcon asked Charles Frend to re-shoot it with Hawkins keeping a grip on himself. It was played that way and Balcon pronounced it absolutely perfect. Then two days later, after another viewing, it was decided that a little emotion was needed after all; the scene was re-shot with just an odd tear or two and again the verdict was that it was now dead right. Hawkins was amused to note that in the final version of the film, the original first take was used. In his second autobiography, Donald Sinden wrote:
Ships Compass Rose was portrayed by the Flower-class corvette (K32). The
Admiralty had disposed of all its wartime corvettes, but
Coreopsis was located in
Malta by one of the film's technical advisers, Capt.
Jack Broome DSC RN (who had been escort commander of the ill-fated
Convoy PQ 17).
Coreopsis had been loaned to the
Hellenic Navy and renamed
Kriezis, and was awaiting a tow back to England and the breaker's yard.
Compass Rose carries the
pennant number "K49", which was in reality the number of HMS
Crocus.
Saltash Castle was portrayed by Castle-class corvette , pennant F362, as in the film. Although she had been paid off in 1947, she was held in reserve until broken up in 1958 and so could be made available for use in the film. In the book, the new ship which replaced
Compass Rose was a fictional HMS
Saltash. These ships were significantly larger than the Castle-class corvettes, but had been paid off or sold abroad when the film was made. (In 1954 a recommissioned
Royal Canadian Navy River-class frigate was made available to play the fictional HMS
Rockhampton in the
John Wayne film
The Sea Chase.) In the film, when boarding their new ship, the characters of Ericson and Lockhart remark that neither of them have heard of a castle in
Saltash – in reality there is no such thing, although there are a number of fortifications in the local area. Both ships were based in
Plymouth, with
Plymouth Sound standing in for the
River Mersey. The scenes of the ships at sea were filmed in the English Channel just out of sight of land. These coastal waters and a summer shooting schedule meant that the sea was generally too calm to portray conditions on the Atlantic in winter, so the ships were taken to the
Portland Race. Although only a couple of miles offshore, a number of conflicting tidal streams and a sandbank provide predictable, albeit often dangerous, large waves and a disturbed sea. Ships usually deliberately avoid the Portland Race but
Compass Rose was taken straight through during the peak of the tide to get the required shots. ==Reception==