'Igel' (i) was a U-boat wolfpack double operation in the North Atlantic against the MKS.38, SL.147, UC.12, ON.223, HX.277, OS.67, KMS.41, ONS.29, ON.224, OS.68 and KMS.42 convoys (3/17 February 1944).
The 'Igel I' wolfpack comprised U-212, U-283, U-386, U-406, U-441, U-545, U-546, U-547, U-549, U-666, U-714, U-764, U-984, U-985 and U-989, and for the loss of Oberleutnant Günter Ney’s U-283, Kapitänleutnant Gert Mannesmann’s U-545 and Oberleutnant Ernst Wilberg’s U-666 sank only the 1,735-ton British Margit of the UR.108 convoy.
The 'Igel II' wolfpack comprised U-91, U-238, U-256, U-264, U-281, U-424, U-437, U-445, U-603, U-608, U-650, U-709, U-731, U-734 and U-963, and for the loss of Kapitänleutnant Horst Hepp’s U-238, Oberleutnant Günter Lüder’s U-424 and Oberleutnant Hans-Jörg Blauert’s U-734 sank no ship.
From 3 February the U-boats operating to the west of Ireland were concentrated singly and in loose formation as the 'Igel I' and 'Igel II' wolfpacks to locate and attack the ONS.29 and ON.223 convoys respectively. U-257, U-260 and U-846 were soon detached to operate separately as meteorological reconnaissance boats. To the north, U-985 sank Margit of the UR.108 convoy on passage from Iceland to Loch Ewe, and on 5 February U-256 shot down a Consolidated Liberator long-range maritime reconnaissance bomber of the RAF’s No. 53 Squadron.
The 'Igel I' boats were deployed against the SL.147/MKS.38 combined convoy, whose location was reported by Junkers Ju 290 long-range maritime reconnaissance aircraft of the Fernaufklärungsgruppe 5 on 6 February to the north of the Azores islands group, and again on 7 and 8 February. The convoy was supported by Commander M. J. Evans’s British Escort Group B3 (Polish destroyer Burza, frigates Towy and Free French Découverte, corvettes Orchis, Narcissus and Free French Roselys, Aconit and Renoncule, and anti-submarine trawler Northern Spray). In further support was Captain F. J. Walker’s 2nd Support Group (escort carriers Activity and Nairana, and sloops Wild Goose, Starling, Kite, Magpie and Woodpecker).
On 8 February Wild Goose located U-762, which was sunk by Starling and Woodpecker. Early on 9 February U-734 and U-238 only just missed Wild Goose and Starling, and Kite and Magpie respectively, and were sunk after long searches. During this operation convoy UC.12, supported by a US escort group, passed farther to the north of the 'Igel' boats.
On 10 February U-256 fired torpedoes at the HX.277 convoy’s escorts, which were the British Escort Group B1 and the six frigates of the Canadian 6th Support Group, but all of them missed. In the evening of 10 February, and during the following night, aircraft of Air Vice Marshal L. H. Slatter’s No. 15 Group of Air Chief Marshal Sir William Sholto Douglas’s RAF Coastal Command flew many sorties to cover both HX.277 and the outbound ON.223, the latter being supported by Commander P. W. Gretton’s Escort Group B7, Commander G. A. G. Ormsby’s 10th Support Group (frigates Spey, Rother, Findhorn and Lossie) and the escort carriers Fencer and Striker.
On 10 February U-666 was lost to unknown causes, and on the following day U-424 was sunk by Wild Goose and Woodpecker. In the process, U-545 and U-283 used their newly installed 37-mm anti-aircraft cannon to shoot down a Leigh Light-equipped Vickers Wellington medium-range anti-submarine aeroplane of the RAF’s No. 612 Squadron and the RCAF’s No. 407 Squadron respectively, but were themselves then sunk, U-545 by a Wellington of the RAF’s No. 612 Squadron and U-283 by a Wellington of the RCAF’s No. 407 Squadron. U-714 rescued the crew of U-545.
Somewhat farther to the south, in the evening of 10 February and during the night of 10/11 February, U-731, U-413 and U-437 made several universally unsuccessful attack the escorts of the OS.67/KMS.41 convoy’s support, which comprised the 39th Escort Group strengthened by the escort carrier Pursuer.
During the evening of 12 February seven Heinkel He 177 long-range heavy bombers of the II/Kampfgeschwader 40 tried to attack the convoy but were repelled by Pursuer's fighters, which shot down one He 177 and a contact-keeping Focke-Wulf Fw 200 Condor long-range maritime reconnaissance aeroplane.
On 13 February German air reconnaissance to the west of the North Channel, spotted one of the incoming convoys, HX.277, CU.13 or SL.147, supported by the carriers Activity and Nairana. Farther to the west, U-445 missed a destroyer escort of Commander R. H. Mills’s British 3rd Support Group and was then damaged in a counterattack.
On 14 February a Ju 290 and two Junkers Ju 88 aircraft, flying to the west of the North Channel, spotted the ONS.29 convoy supported by Commander R. A. Currie’s British Escort Group B6 (destroyers Fame, Vanquisher and Vesper, frigate Deveron and corvettes Kingcup, Vervain and Norwegian Eglantine, Rose and Acanthus), the ON.224 convoy supported by the Canadian Escort Group C1, and the combined OS.68/KMS.42 convoys.
One of these was located once again on 15 February by the three Ju 290 aircraft launched specifically for the task, and on 16 February two Ju 290 aircraft were lost. On 16 February the HX.278 convoy approached from the south-west with support from Commander D. G. F. W. MacIntyre’s British Escort Group B2, the 2nd Support Group, and the British Escort Groups B2 and B7. Equipped with 37-mm anti-aircraft cannon, U-546 and U-984 were able to beat off night attacks, but could not get themselves into position to attack the convoy.