This was a U-boat wolfpack operation, in tandem with ‘Stier’ (i), in the Atlantic against the SC.97 and RB.1 convoys (27 August/26 September 1942).
The wolfpack comprised U-91, U-92, U-211, U-218, U-380, U-404, U-407, U-409, U-411, U-461, U-584, U-594, U-604, U-608, U-609, U-659 and U-756, and for the loss of Kapitänleutnant Klaus Harney’s U-756 sank 15 ships (79,331 tons including the British destroyer Veteran and Canadian destroyer Ottawa) and damaged four other ships (36,240 tons) of the SC.97, ON.127 and RB.1 convoys.
In its initial form, the ‘Vorwärts’ wolfpack comprised U-609 coming from Iceland, and U-91, U-92, U-211, U-407, U-409, U-411, U-604, U-659 and U-756; U-604 had been stationed since 15 August in a waiting area and had sunk the 7,906-ton Dutch Abbekerk in that area.
On 31 August Oberleutnant Klaus Rudloff’s U-609 sighted and reported the SC.97 convoy of 58 laden ships, supported by Lieutenant Commander T. Taylor’s Canadian Escort Group C2 (British destroyers Burnham and Broadway, and Canadian corvettes Brandon, Dauphin, Drumheller and Morden) toward the northern end of the U-boats' patrol line. The boat launched an immediate attack and sank the 4,663-ton Norwegian Bronxville and 5,625-ton Panamanian Capira, but was then driven off by the escorting warships.
By the morning of 1 September the Germans had concentrated six U-boats in the area of the convoy, but the attacks of U-604 and U-756 were unsuccessful. During the day the boats were then driven off by a Consolidated Catalina flying boat of the US Navy’s VP-73 squadron operating from Iceland, which also inflicted minor damage on U-91. On the same day, Harney’s U-756 was sunk by Morden. During the night of 1/2 September only U-91 was able to make any attack, but this was again unsuccessful, and at the break of day on 2 September the Germans decided to call off the operation as the Allied air escort was now too strong.
The ‘Vorwärts’ wolfpack was then reinforced by boats of the ‘Stier’ (i) wolfpack, which had been created from outbound boats during the attack on the SC.97 convoy, and from 4 September comprised U-91, U-96, U-211, U-218, U-380, U-404, U-407, U-411, U-584, U-594, U-608 and U-659. During the evening of 9 September U-584 sighted and reported the ON.127 convoy of 32 ships supported by Lieutenant Commander A. H. Dobson’s Canadian Escort Group C4 (destroyers St Croix and Ottawa, and corvettes Amherst, Arvida, Sherbrooke and British Celandine).
The ON.127 convoy, outbound from the UK to North America, was the only Allied convoy of 1942/43 in which all the U-boats deployed against it launched torpedoes. The ships had departed Liverpool on 4 September, and were met at about 12.00 on 5 September by the Escort Group C4. The warships carried the Type 286 metric-wavelength radar, though none of the sets was serviceable, and Celandine carried Type 271 centimetric-wavelength radar. None of the ships carried HF/DF high-frequency direction-finding equipment.
The ‘Vorwärts’ wolfpack was forming with U-91, U-92, U-96, U-211, U-218, U-380, U-404, U-407, U-411, U-584, U-594, U-608 and U-65 in an extended north/south search line across the convoy’s expected path about 500 miles (800 km) to the west of Ireland, just beyond the range of land-based aircraft, as the convoy departed Liverpool. Kapitänleutnant Joachim Deecke’s U-584 sighted and reported the convoy on 9 September, but lost contact during the evening of the same day. Oberleutnant Hans-Jürgen Hellriegel’s U-96 regained contact at about 12.00 on 10 September, and torpedoed and sank the 6,313-ton Norwegian tanker Svene and 4,241-ton Belgian Elisabeth van Belgie , and also torpedoed and damaged the 12,190-ton British tanker F. J. Wolfe, in a single submerged daylight attack. Sherbrooke fell back to aid the torpedoed ships while St Croix, Ottawa and Celandine searched unsuccessfully for U-96. F. J. Wolfe was able to regain its station with the convoy. Ottawa continued to patrol astern of the convoy after St Croix and Celandine resumed their normal patrol stations.
A co-ordinated night attack on the convoy later began with Korvettenkapitän Hans Stock’s U-659 torpedoing and damaging the 8,029-ton British tanker Empire Oil during the evening of 10 September. St Croix made sonar contact immediately before the U-boat’s attack, and Celandine, Ottawa and St Croix searched for U-659 after the attack. St Croix and Ottawa then dropped back to rescue 23 of the stricken tanker’s 41-man crew. Korvettenkapitän Otto von Bülow’s U-404 torpedoed and damaged the 7,417-ton Norwegian tanker Marit II, Kapitänleutnant Rolf Struckmeier’s U-608 launched torpedoes which missed the convoy, Kapitänleutnant Richard Becker’s U-218 torpedoed and damaged the 7,361-ton Norwegian tanker Fjordaas, and Kapitänleutnant Adolf Oelrich’s U-92 and Kapitänleutnant Friedrich Mumm’s U-594 launched torpedoes which missed the convoy before Ottawa, St Croix and Celandine rejoined. Sherbrooke remained astern of the convoy aiding the ships torpedoed by U-96, and rescued all but one of the crew of the sinking Svene and Elisabeth van Belgie.
The remaining escorts counterattacked, and depth charge damage forced U-659 and U-218 to return to port. Both Marit II and Fjordaas were able to regain their stations in the convoy. Empire Oil was later sunk astern of the convoy by U-584. None of the Allied escort ships’ radar equipments was functional on 11 September, on which date U-584 torpedoed and sank the 4,884-ton Norwegian Hindanger in a submerged daylight attack while St Croix investigated a sighting some 6 miles (10 km) away. Amherst fell back and rescued all but one of Hindanger’s crew.
The presence of a Consolidated Liberator long-range patrol bomber of the RAF’s No. 120 Squadron prevented further daylight attacks on 11 September, but U-96 sank a 415-ton Portuguese sailing trawler by gunfire in the vicinity of the convoy. In co-ordinated night attacks, Kapitänleutnant Josef Röther’s U-380 missed with a salvo of four torpedoes, Kapitänleutnant Karl Hause’s U-211 torpedoed and damaged the 13,797-ton British whale factory ship Hektoria and 6,849-ton British Empire Moonbeam, U-92 missed Ottawa with four torpedoes, and U-404 torpedoed and damaged the 9,272-ton Norwegian tanker Daghild before Amherst and Sherbrooke rejoined the convoy. Daghild maintained station in the convoy and Arvida rescued all but four of the 140 crew from Hektoria and Empire Moonbeam before those ships were sunk astern of the convoy by U-608.
Excellent visibility on 12 September allowed a close forward screen of four escorts to discourage U-boats sighted up to 7 miles (11.25 km) distant. Kapitänleutnant Ernst-Ulrich Brüller’s U-407 and U-594 launched torpedoes unsuccessfully that night. Later U-594 sank the straggling 6,131-ton Panamanian Stone Street as the convoy came within range of Canadian Vickers Canso patrol flying boats from Botland, Newfoundland, on 13 September.
The escort was reinforced at dusk by the Canadian destroyer Annapolis and the British destroyer Witch from the Newfoundland-based Western Local Escort Force. Both U-91 and Kapitänleutnant Johann Spindlegger’s U-411 launched torpedoes unsuccessfully, while U-91 torpedoed the destroyer Ottawa in the pre-dawn hours of 14 September, the destroyer sinking with 114 of her crew.
The rest of the convoy reached New York City on 20 September 1942.
After refuelling from U-461 between 16 and 18 September, U-91, U-96, U-211, U-380, U-404, U-407 and U-584 established new patrol line to the east of the Newfoundland Bank on 20 September, and during the following few days these first boats were supplemented by U-260, U-582 and U-619. Between 18 and 24 September the boats sank a number of independently routed or straggling ships: U-380 despatched the 2,994-ton Norwegian Olaf Fostenes, U-211 the 11,237-ton US tanker Esso Williamsburg, U-582 the 2,993-ton Norwegian Vibran, and U-619 the 7,176-ton US John Winthrop.
On 23 September U-404 spotted and reported the RB.1 convoy of eight passenger ships from the US eastern coast escorted by the British destroyers Vanoc and Veteran. Apart from the ‘Vorwärts’ wolfpack, the ‘Pfeil’ wolfpack (U-216, U-356, U-410, U-595, U-607, U-617 and U-618) was instructed to proceed to the area after ending its attack on the SC.100 convoy farther to the east, but because of the convoy’s high speed the boats have difficulty reaching it. During the night of 24/25 September U-211 and U-260 made unsuccessful attacks. In the afternoon of 25 September, however, Oberleutnant Karl-Otto Schultz’s U-216 sank the 4,989-ton British Boston, and in the evening U-96 torpedoed and damaged the 4,989-ton British New York, which was later torpedoed for a second time by U-91 and finally sunk by Veteran. Attacks by U-410 (twice), U-91 and U-356 failed. In the morning of 26 September U-404 sank Veteran and in the evening U-619 the straggling 1,547-ton British Yorktown.