COMPASS ROSE
As a point of interest the real name of the Flower Class corvette in this movie was, HMS CROCUS (K-49). She saw action off Freetown Sierra Leone West Africa in 1942. So Freetown being a assembly point and anchorage for allied convoys naturally attracted U-Boats.
During total darkness CROCUS, under the command of a New Zealander J. F. Holm; who in peacetime was a Merchant Marine Officer, sniffed out and picked an argument with U-333, which was lurking on the surface looking for a kill. She managed to ram the U-Boat abaft the conning tower. The U-Boat broke loose and scraped down the corvette's port side, punching a hole in her at the water line. CROCUS rammed her again, but no luck. The U-Boat like its wounded skipper, Peter Cremer, was a tough cookie. She slipped away in the tropical darkness and shaped a course for the U-Boat pens on the French Biscay Coast. U-333 was later lost with all hands off the Isles of Scilly, near Lands End. Anyone out there who is interested can find more information about U-333 on www.uboat.net. It's a website with a mine of information about the German Navy's U-Boat fleet in World War Two.
I have just been breezing through the trivia of, "The Cruel Sea". It was not the above mentioned Flower Class corvette. It was indeed HMS COREOPSIS K32. Then transferred to the Royal Hellenic Navy and renamed RHN KRIEZIS from 1943 to 1952. She was decommisioned and returned to Sunderland, UK, for scrapping in 1952.
All the best, smiley-39