I have stumbled upon some further information. From pp 116-7 of 'Lilliput Fleet' (1957) by A. Cecil Hampshire (ISBN :

"...But there were many grim days ahead. Japanese submarines were roaming the Indian Ocean. In addition to at least five well-armed surface raiders the Germans had some two hundred and fifty U-boats operating at sea. By the end of 1941 they were becoming active off the east coast of the United States, sinking American tankers by gunfire and torpedoes. Since the U.S. Navy was deficient in anti-submarine vessels the British Admiralty offered the loan of twenty-four A/S-fitted trawlers to patrol in the threatened area. The offer was gratefully accepted and in March, 1942, British fishing trawlers-turned-warships came under American command.

These 'rugged little coal-burners' as the Americans called them, none grossing less than 500 tons, were some of the cream of the peacetime Hull and Grimsby fishing fleets. From the former port came the Arctic Explorer, Kingston Ceylonite, Lady Elsa, Lady Rosemary, Pentland Firth, St Cathan, St Loman, St Zeno, and the Stella Polaris; from the latter the Befordshire, Coventry City, Hertfordshire, Le Tigre, Northern Chief, Northern Dawn, Northern Duke, Northern Isles, Northern Princess, Norwich City and Wellard; the Senateur Duhamel, a 900-ton giant of French registry which had been brought over to Britain after the fall of France, Cape Warwick, and the Wastwater and Buttermere, two vessels of the new Admiralty-designed 'Lakes' class. Four of the trawlers were stationed off New York, in the Hampton Roads, eight at Charlestown and six at Boston.

Five were sunk during their service in American waters; the St Cathan, Senateur Duhamel and the Pentland Firth due to collisions, the Kingston Ceylonite by mine, and the Bedfordshire torpedoed by a U-boat. One trawler, the Northern Princess, was lost in the Atlantic from an unknown cause. To balance these casualties, however, the Le Tigre, living up to her name, sank the U-215. By October eighteen of them were on their way back east for, due to a spurt of U-boat activity in South African waters, the Admiralty had to request their return to strengthen our convoy escorts in the South Atlantic..."

Rob Hoole
www.mcdoa.org.uk