Convoy SC 104 Convoy SC - 104 was the 104th of the numbered series of World War II Slow Convoys of merchant ships from Sydney , Cape Breton Island to Liverpool . During October 1942 , a U - Boat wolf pack sank eight ships from the convoy . The convoy escorts sank two of the attacking submarines . Background . As western Atlantic coastal convoys brought an end to the second happy time , Admiral Karl Dönitz the " Befehlshaber der U - Boote " ( " BdU " ) or commander in chief of U - Boats , shifted focus to the mid - Atlantic to avoid aircraft patrols . Although convoy routing was less predictable in the mid - ocean , Dönitz anticipated that the increased numbers of U - boats being produced would be able to effectively search for convoys with the advantage of intelligence gained through " B - Dienst " decryption of British Naval Cypher Number 3 . However , only 20 percent of the 180 trans - Atlantic convoys sailing from the end of July 1942 until the end of April 1943 lost ships to U - boat attack . Forty - seven ships departed New York City on 3 October 1942 and were met by Mid - Ocean Escort Force Group B - 6 consisting of the E and F class destroyer " Fame " and V and W class destroyer " Viscount " , with the Norwegian - manned Flower class corvette s " Potentilla " , " Eglantine " , " Montbretia " , and " Acanthus " and the Convoy rescue ship " Goathland " . Opposing this force was the U - boat patrol group " Wotan " comprising 8 boats : " U - 221 " , " U - 258 " , " U - 356 " , " U - 607 " , " U - 618 " , " U - 661 " , " U - 353 " , and " U - 254 " . Action . The convoy was found and reported by " U - 258 " on 11 October , and the other " Wotan " boats were ordered to join . By the evening of 12 October , " U - 258 " had been joined by " U - 221 " and " U - 356 " , and during the night of 12 / 13 October these boats attacked . " U - 258 " and " U - 356 " were unsuccessful , being driven off by the escorts , but " U - 221 " was able to sink three ships : the Norwegian freighters " Senta " , and " Fagersten " , and the British freighter " Ashworth " . On the 13th the three U - Boats continued to shadow the convoy , and were joined during the day by five other boats . On the night of the 13 / 14 October the wolf pack attacked again . This time " U - 221 " sank two ships : the American freighter " Susana " and the British whale factory ship " Southern Empress " . " U - 607 " torpedoed the Greek freighter " Nellie " , which later sank , but was itself attacked and severely damaged , and was forced to return to France for repairs . " U - 661 " torpedoed the Yugoslavian freighter " Nikolina Matkovic " , and " U - 618 " torpedoed the " Empire Mersey " . Throughout 15 October the " Wotan " boats shadowed SC 104 , but were unable to mount any successful attacks that night . On 15 October , " Viscount " detected " U - 661 " in fog , and attacked with gun - fire , ramming and depth - charges . " U - 661 " was destroyed , but Viscount was also damaged , and had to finish the voyage as part of the convoy . On 16 October " U - 353 " was sighted by " Fame " which attacked and destroyed her by ramming , again suffering damage in the process . Command of the escort passed to Monsen in " Potentilla " , who was able to make an attack on a contact later that day . No identification was made , or result credited , but post - war examination shows that " U - 254 " was severely damaged in this attack and forced to retire to base . On the 16 and 17 October SC 104 came in range of allied air patrols , long – range B - 24 Liberator s and Catalina flying boats . These were able to break up any further attacks and on the 17th , Dönitz ceased further operations against SC 104 . The remainder of the voyage was unhindered , and the convoy reached Liverpool on 21 October . SC 104 lost 8 ships of 44 , 000 tons , with 2 escorts damaged , and saw the destruction of 2 U - boats with the damaging of 2 more . Notes .