This was a U-boat wolfpack operation in the Atlantic against the SC.94 convoy (3/11 August 1942).
The wolfpack eventually comprised U-71, U-176, U-210, U-256, U-379, U-454, U-552, U-593, U-595, U-597, U-605, U-607, U-660 and U-704, and for the loss of Korvettenkapitän Rudolf Lemcke’s U-210 and Korvettenkapitän Paul-Hugo Kettner’s U-379 sank 11 ships (59,560 tons) and damaged three ships (21,074 tons).
The SC.94 slow convoy was routed from Sydney, Cape Breton island, to Liverpool, and became involved in a battle with the U-boat wolfpack between 5 and 10 August. Some 30 merchant ships departed Sydney on 31 July 1942, and were met by Lieutenant Commander A. Ayre’s Canadian Escort Group C1 (destroyer Assiniboine and corvettes Battleford, Chilliwack, Dianthus, Orillia and British Nasturtium and Primrose).
Of the initial wolfpack complement of U-71, U-210, U-379, U-454, U-593, U-597, U-607 and U-704, Kapitänleutnant Gerd Kelbling’s U-593 reported the convoy on 5 August, and then sank the 3,616-ton Dutch Spar before being driven off, together with U-595, by Nasturtium and Orillia. Assiniboine located and sank Lemcke’s U-210 on the following day, first depth-charging the boat and forcing it to the surface, where it was further damaged by gunfire being rammed.
U-595 was the first of a number of additional boats to join the ‘Steinbrinck' wolfpack during 7 August, later arrivals being U-174, U-176, U-256, U-438, U-660 and U-705. During the afternoon of the same day U-607 missed a group of stragglers, and then during the night U-704 and in the morning of 8 August U-660 each missed the convoy. At about 12.00 on 8 August U-605 and U-597 made unsuccessful efforts to attack stragglers. Korvettenkapitän Paul-Hugo Kettner’s U-379 sank the 2,537-ton British Anneberg and the 6,367-ton US Kaimoku during the afternoon of 8 August, while Kapitänleutnant Reiner Dirkson’s U-176 sank the 3,956-ton British Kelso, 4,817-ton British Trehata and 7,914-ton Greek Mount Kassion. Three undamaged ships were abandoned in the resulting panic. One of them, the 3,701-ton British Radchurch, was later sunk by Dirkson’s U-176. In this period 41 merchant seamen were lost, together with 3,000 tons of steel, 3,000 tons of food, 3,200 tons of wood pulp, 2,000 tons of ammunition and 16,218 tons of general cargo, iron ore, and army stores.
The British flotilla leader Broke and Free Polish destroyer Błyskawica now arrived to reinforce the escort as Dianthus left the convoy for the repair of the damage she had sustained in her ramming and sinking of U-379. All the escorts but Primrose remained during the night to tackle the U-boats, supported by the HF/DF on the destroyers, and Broke was just missed by U-595. All the German efforts to reach and attack the merchant ships were thwarted, however, and only U-607 was able to fire, albeit unsuccessfully, and then maintain contact.
Despite the appearance of Consolidated Liberator long-range patrol bombers of the RAF’s No. 120 Squadron from Northern Ireland during the afternoon of 9 August, U-174, U-254, U-256 and U-704 in the afternoon and evening of 9 August, and U-597 in the morning of 10 August were able to fire, though they scored no hits. The fact that some escorts had remained behind the convoy to deal with the boats which had been located made it possible for Kapitänleutnant Rudolf Franzius’s U-438 to sink the 4,439-ton Greek Condylis during daylight on 10 August, and for Oberleutnant Götz Baur’s U-660 to sink the 3,807-ton British Cape Race, 6,259-ton British Empire Reindeer and 6,008-ton British Oregon: 20 merchant seamen were lost together with 1,040 tons of steel, 3,979 tons of lumber, 14,057 tons of general cargo and 6,924 tons of grain and trucks.
The remainder of the convoy reached Liverpool on 13 August.