This was a U-boat wolfpack operation in the Atlantic against the ON.111 and ON.113 convoys (13 July/1 August 1942).
The wolfpack comprised U-43, U-71, U-86, U-90, U-379, U-454, U-461, U-552, U-597, U-607 and U-704, and for the loss of Kapitänleutnant Hans-Jürgen Oldörp’s U-90 sank two ships (12,078 tons) and damaged one 8,093-ton ship.
On 13 July U-71 spotted the ON.111 convoy, supported by the British Escort Group B6, in the area to the south of Iceland, but the boat’s poor sighting report meant that many of the boats started to search in the wrong direction.
U-552 and U-704 were driven off by the escorts on 14 July, and the wolfpack then headed to the south-west without sighting anything further until 23 July, when it was ordered to intercept the ON.113 convoy, which had been located by the German navy’s B-Dienst signals intercept and analysis service. On the following day U-552 spotted the convoy of 33 ships supported by Commander T. Taylor’s Canadian Escort Group C2 (British destroyer Burnham and Canadian destroyer St Croix, and corvettes Brandon, Dauphin, Drumheller and British Polyanthus). St Croix depth-charged and sank U-90 as the boat attempted to maintain contact.
During the first night only U-552 attacked, sinking the 5,136-ton British Broompark and damaging the 8,093-ton British tanker British Merit. In conditions of poor visibility and bad weather, only a few of the wolfpack’s boats managed to approach the convoy on 25 July. Attacks by U-43 and U-597 during the night gained no success, but U-607 torpedoed and damaged the 6,942-ton British Empire Rainbow, which was later despatched by Kapitänleutnant Horst Wilhelm Kessler’s U-704.
On 26 July the wolfpack lost contact with the convoy, and a search on 27 July was unsuccessful. The wolfpack then divided and headed for a replenishment rendezvous with U-461 on 29/30 July, but Kapitänleutnant Ernst Vogelsang’s U-132 sank the 6,734-ton British Pacific Pioneer on 30 July.
On 29 July the outbound U-210 had meanwhile spotted and reported the ON.115 convoy of 41 ships supported by Lieutenant Commander D. C. Wallace’s Canadian Escort Group C3 (destroyers Saguenay and Skeena, and corvettes Agassiz, Gait, Louisburg, Sackville and Wetaskiwin).
On 30 and 31 July the escort repeatedly repelled all five U-boats which made contact, and Kapitänleutnant Victor Vogel’s U-588 was depth-charged and sunk by Skeena and Wetaskiwin.
On 1 August the new ‘Pirat’ wolfpack was established with U-164, U-210, U-217, U-511 and U-553, and the replenished U-43, U-71, U-454, U-552, U-597, U-607 and U-704 of the ‘Wolf’ (i) wolfpack joined this on the following day. In the night Saguenay and Skeena had to break off to refuel, leaving only Agassiz, Louisburg and Sackville with the convoy after Wetaskiwin failed to return after a hunt. During the afternoon, however, the escort was strengthened arrival of two destroyers (British Witch and Canadian Hamilton) of the Western Local Escort Force.
On 2 August U-552 sighted the convoy and brought up U-71, U-217, U-553, U-597 and U-704. U-552 torpedoed and damaged the 10,627-ton British tanker G. S. Walden and 7,176-ton Belgian Belgian Soldier, the latter being sunk on the following day by Kapitänleutnant Ernst Mengersen’s U-607. Korvettenkapitän Karl Thurmann’s U-553 sank the 9,419-ton British Lochkatrine. Other attacks by U-71, U-217 and U-552 on the convoy and by U-597 on a straggler all failed, and on 3 August the Germans called off the operation in the face of steadily worsening visibility.