Convoy SC 48

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 (HMS Highlander and HMS Broadwater) from TC 14; two Royal Navy corvettes (HMS Abelia and HMS Veronica) from ON 25; and a RCN corvette (HMCS Pictou) 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 sunk by U-568 on the 17th, but more probably on the 16th by U-432.

After midnight on 15/16 October, 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 16 October and again closed in.

Also in the afternoon of 16 October, the first reinforcements arrived, in the form of DesRon 13. This comprised the destroyers USS Decatur, USS Kearny, and USS Livermore, led by USS Plunkett (Capt L Thebaud). These were joined later by Thebaud's fifth destroyer, USS Greer, accompanied by HMCS Pictou. As senior officer present, Thebaud assumed command of the escorts. Though 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 16 October BdU had gathered ten 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 16/17 October the pack attacked, closing in with little interference from the escorts. U-553 sank Bold Venture at about 8 PM. 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, USS Kearny stopped to avoid a collision with a corvette, and was torpedoed by U-568. Kearny was severely damaged, with 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.

At dawn on 17 October the convoy was joined by Western Approaches escort. This was EG 3, comprising four destroyers (HMS Bulldog, HMS Amazon, HMS Richmond and HMS Georgetown) and one corvette (HMS Heartsease), 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.

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.

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.