Convoy SC 48 SC 48 was a North Atlantic convoy of the SC series which ran during the battle of the Atlantic in World War II . It was notable for being the occasion of the " Kearny " incident , which brought the United States one step closer to war with Germany . Prelude . SC 48 was an east - bound convoy of 52 ships , carrying war materials and sailed from Sydney , Cape Breton on 5 October 1941 bound for Liverpool . It was under the command of Commodore HM Sanders in the MV " Castalia " . It was escorted by a Canadian escort group consisting of the destroyer ( Lt Cdr SW Davis as Senior Officer Escort ) , and seven corvette s ; , , , , , and the Free French " Mimosa " . Opposing this force was the patrol line " Mordbrenner " , which was to have comprised eight U - boats and was in the process of forming south of Iceland near the Mid - Ocean Meeting Point . This was the point at which North Atlantic convoys were handed over between the Ocean and the Western Approaches escorts at this stage of the Atlantic campaign . Allied intelligence became aware of the presence of " Mordbrenner " , and started to divert the convoys then at sea , but a loss of Ultra intelligence on 12 / 13 October left SC 48 in the dark ; and on the night of 14 / 15 October it was sighted by " U - 553 " ( K / L Karl Thurmann ) . At this point in time SC 48 was in some disarray ; 11 of its ships , including " Castalia " , were straggling following heavy weather on the night of 9 / 10 October . " Columbia " and two of the corvettes , " Camrose " and " Rosthern " , were detached looking for them . A third corvette , " Shediac " was also separated by the storm and out of radio contact . On 14 October SC 48 ’ s escort comprised just four corvettes ; " Wetaskiwin " ( as Acting SOE ) , " Baddeck " , " Gladiolus " and " Mimosa " . Action . 15 October 1941 . In the early hours of 15 October Thurmann of " U - 553 " reported his contact to U - boat Command ( BdU ) and was ordered to shadow , whilst other U - boats were gathered for the attack . However Thurmann chose to attack that night , and succeeded in sinking two ships , " Silvercedar " , which lost 21 crew , and " Ila " , most of whose crew were saved . " U - 553 " was sighted by " Silverhelm " , the next ship in the column , which attempted to ram , but failed ; " U - 553 " was also sighted by " WC Teagle " , but she was unable to bring her gun to bear before " U - 553 " escaped . On 15 October Enigma was re - acquired and Western Approaches Command realized a major attack was building ; a number of escorts from nearby convoys were diverted to reinforce SC 48 . First a force of US destroyers ( DesRon 13 ) , detached from ON 24 ; two Royal Navy destroyers ( and HMS " Broadwater " ) from TC 14 ; two Royal Navy corvettes ( and ) from ON 25 ; and a RCN corvette ( ) from Iceland . Later on 15 October " Columbia " rejoined , while " U - 553 " was joined by two more boats ; " U - 558 " ( Günther Krech ) and " U - 568 " ( Joachim Preuss ) . As " U - 553 " continued to shadow , she was sighted by " Columbia " , who attacked her , driving her away , but with no damage ; " U - 553 " fired a torpedo at " Columbia " , which missed . During the day " U - 558 " joined , having encountered the ship " Vancouver Island " sailing independently ; she was sunk with the loss of all 73 crew and 32 passengers . Before nightfall " U - 568 " also arrived , and the three boats prepared to attack . As darkness fell on the night of 15 / 16 October the U - boats attacked again . " U - 568 " attacked and sank " Empire Heron " , " Gladiolus " counter - attacked , and " U - 568 " was driven off . " Gladiolus " then detached to pick up survivors , but never rejoined the convoy ; she was lost with all hands , reportedly by " U - 568 " on the 17th , but more probably on the 16th by " U - 432 " . 16 October 1941 . After midnight on 15 / 16th , SC 48 made an emergency turn to port , followed before dawn by a turn to starboard , in an attempt to shake off pursuit ; this was initially successful , but the pack regained contact in the afternoon of 16th and again closed in . Also that afternoon of 16 October the first reinforcements arrived , in the form of DesRon 13 ; this comprised the destroyers , , and , led by ( Capt L Thebaud ) . These were joined later by Thebaud ' s fifth destroyer , , accompanied by HMCS " Pictou " . As senior officer present Thebaud assumed command of the escorts ; however although he had seniority Thebaud had little experience in escort work , and a number of mistakes were made allowing the U - boats to mount a successful attack that night . By nightfall on 16th BdU had gathered nine U boats for the attack ; the three " Mordbrenner " boats plus seven newcomers , ( " U - 101 " , " U - 109 " , " U - 208 " , " U - 374 " , " U - 432 " , " U - 502 " and " U - 573 " ) During the night of 16 / 17th the pack attacked , closing in with little interference from the escorts . " U - 553 " sank " Bold Venture " at about 8pm . " U - 558 " sank " WC Teagle " about an hour later ; " Erviken " was attacked and sunk as she stopped to pick up survivors and " Rym " was also sunk as she slowed to do the same . " U - 432 " sank " Evros " and " Barfonn " just before midnight . Just after midnight " U - 568 " hit a destroyer which had stopped to avoid a collision with a corvette ; this was USS " Kearny " . She was severely damaged , losing 11 killed and 22 wounded , but was saved by effort of the crew . She was detached to Iceland , escorted by " Decatur " and " Greer " . In the early hours of 17 October more warships arrived ; HMS " Highlander " and " Broadwater " from TC 14 , and HMS " Abelia " and " Veronica " from ON 25 . With this reinforcement further attacks were warded off , but the pack remained in contact , awaiting a further opportunity . 17 October 1941 . At dawn on 17 October the convoy was joined by Western Approaches escort ; This was EG 3 , comprising four destroyers ( , , and HMS " Georgetown " ) and one corvette ( ) , with two trawlers and a rescue ship . The RCN group departed at this point , being low on fuel ; also DesRon 13 left to follow " Kearny " to Iceland . The pack was still in contact , but all further attacks were frustrated by the escort . " Veronica " made a determined attack on a contact and claimed a kill , but no U boat loss was confirmed . A Catalina flying air cover also bombed " U - 558 " which was damaged , but continued to shadow until the attack was called off . 18 October 1941 . On the night of 17 / 18 October the pack tried again ; all attacks were repelled but U - 101 fired on " Broadwater " , causing her mortal damage ; she remained afloat for another 12 hours , but had to be abandoned and sunk . On 18 October BdU ordered the attack discontinued . " Mordbrenner " , which had never completely formed , was dissolved , the remaining boats being sent west to form a new patrol line off the coast of Canada . The remaining boats were moved east to form a new patrol line , " Reisswolf " , south - east of Greenland . 22 October 1941 . SC 48 continued without further loss , the 31 ships arriving at Liverpool on 22 October 1941 . The 11 stragglers which had become separated in the storm on 10 October had been gathered up by " Camrose " and " Rosthern " . Led by Commodore Sanders in " Castalia " and with just two corvettes as escort this group was able to make the crossing without interference , arriving in Britain 10 days after the main body . Conclusion . This was undoubtedly a victory for the U boat arm ; SC 48 lost nine ships of 51 , 093 tons , while the escort lost two ships sunk and onr damaged ; no U boats were lost . Some of the losses , in the face of a large and powerful escort force , can be attributed to Captain Thebaud ’ s inexperience in convoy escort duty . This , and other cases , led to the practice of leaving the escort group commander of the convoy in charge of its defence , regardless of seniority ; a major break with tradition . The attack on " Kearny " and the loss of American lives was seen as an affront to the United States , and was another step out of her isolation in World War II . Tables . Allied ships sunk Allied warships hit U - boats hit