This was a U-boat wolfpack operation, in concert with ‘Ungestüm’, in the Atlantic against the ONS.154 convoy (22/31 December 1942).
The wolfpack comprised U-123, U-203, U-225, U-260, U-356, U-406, U-440, U-441, U-659, U-662 and U-664, and for the loss of Oberleutnant Günther Ruppelt’s U-356 sank eight ships (39,849 tons) and damaged six ships (36,042 tons) in attacks on the ONS.154 convoy.
The convoy’s 46 ships departed Liverpool on 18 December, and were met by Commander G. S. Windeyer’s Canadian Escort Group C1 comprising the destroyer St Laurent and corvettes Battleford, Chilliwack, Kenogami, Napanee and Shediac. The convoy included the HF/DF-equipped rescue ship Toward and the Free French-crewed 2,456-ton special service vessel (Q-ship) Fidelity, which was armed with four 4-in (102-mm) guns and four torpedo tubes, equipped with a defensive torpedo net, and carried two landing craft, two Vought OS2U Kingfisher floatplanes, and the motor torpedo boat MTB-105.
The convoy was routed to the south to avoid storms, and remained distant from escort support groups and out of range of Allied maritime patrol aircraft for longer than most convoys.
Korvettenkapitän Wolfgang Hermann’s U-662 reported the convoy on 26 December, and during the following night Kapitänleutnant Georg Wallas’s U-356 made two approaches to the convoy in which it torpedoed and sank the 5,952-ton British Empire Union, 2,473-ton British Melrose Abbey and 5,254-ton British King Edward, and also torpedoed and damaged the 7,051-ton Dutch Soekaboemi (later sunk by Kapitänleutnant Klaus Hartmann’s U-441) before itself being sunk by St Laurent, Battleford, Chilliwack and Napanee.
The ships sunk in this attack took down with them 37 men as well as 3,403 tons of coal and 5,940 tons of general cargo. The Germans res-established contact with the convoy on 27 December when Oberleutnant Wolfgang Leimkühler’s U-225 spotted and reported the convoy during the afternoon. During the night of 27/28 December, U-225 torpedoed the 7,087-ton tanker Scottish Heather, which survived and remained with the convoy under tow by Chilliwack. In the morning, after a nine-hour break, the Germans re-established contact, this time courtesy of Kapitänleutnant Hubertus Purkhold’s U-260, which then brought up U-123, U-203, U-225, U-336, U-406, U-440, U-591, U-615 and U-664 during the day and U-435, U-628 and U-662 during the night.
During the co-ordinated attack which followed on the night of 28/29 December, with the boats attacking in quick succession after initial misses by U-203 and U-435, Kapitänleutnant Horst Dieterichs’s U-406 torpedoed and damaged the 5,029-ton British Lynton Grange, 4,871-ton British Zarian and 3,385-ton British Baron Cochrane (later sunk by Kapitänleutnant Karl-Heinz Moehle’s U-123), Kapitänleutnant Hans-Jürgen Zetzsche’s U-591 torpedoed and damaged the 5,701-ton Norwegian Norse King (later sunk by U-435), Kapitänleutnant Hubertus Purkhold’s U-260 torpedoed and sank the 4,893-ton British Empire Wagtail, and Leimkühler’s U-225 torpedoed and sank the 5,273-ton British Melmore Head, and torpedoed and damaged the 5,598-ton British Ville de Rouen (later sunk by Korvettenkapitän Wolfgang Hermann’s U-662), 7,068-ton Empire Shackleton (later sunk by U-435) and 4,919-ton Belgian tanker President Francqui (later sunk by Kapitänleutnant Hans Hunger’s U-336).
Some 149 men and 9,829 tons of coal, 13,497 tons of general cargo, and 2,000 tons of ammunition and aircraft went down with these ships.
Further attacks by U-203, U-435, U-628, U-664 and, once again, U-628 on the escorts and merchant ships were not successful. As many as 12 U-boats were in contact with the convoy, the outnumbered escort was running out of fuel, and Windeyer suffered a nervous breakdown at the scale of losses. Following the loss of the convoy commodore, he invited two fast ships with large passenger complements to escape if they found an opportunity.
The escort was reinforced by the British destroyers Meteor and Milne on the morning of 29 December, and the two fresh destroyers succeeded in driving off U-260, U-455 and U-591. Only U-435 has success on this occasion, sinking the 5,701-ton Norwegian Norse King in a daylight submerged attack.
Fidelity suffered engine trouble while operating independently rescuing survivors. The motor torpedo boat and floatplanes were launched to deter U-boat attacks, and the torpedo net was deployed to foil cautious attacks by U-225 and Kapitänleutnant Ralph Kapitzky’s U-615.
On 29 December U-225 and U-615 made repeated attacks on Fidelity, which managed to avoid the attacks, but then on the following day Korvettenkapitän Siegfried Strelow’s U-435 torpedoed the rescue ship, which sank with 334 men.
U-455 maintained contact with the convoy until the night of 30/31 December, but was unable to bring up any other boats, all of which now proceeded to a rendezvous with U-117 for replenishment. The rest of the convoy reached New York City on 12 January 1943.