'Pfeil' (i) was a U-boat wolfpack operation in the Atlantic against the SC.99 and ON.129 convoys (13/25 September 1942).

The wolfpack comprised U-216, U-221, U-258, U-356, U-440, U-595, U-607, U-615, U-617, U-618 and U-661, and for the loss of none of its own number sank four ships (19,776 tons) of the SC.100 and RB.1 convoys.

After refuelling from U-462, the boats of the 'Lohs' wolfpack (U-135, U-176, U-373, U-432, U-569 and U-755) established a new patrol line on 6 September in the western part of the North Atlantic. Here, on 9 September, Kapitänleutnant Walter Göing’s U-755 sank the 1,827-ton US weather ship Muskeget. From 13 September U-259, U-410 and U-599 joined the wolfpack.

On 18 September, as a result of the decryption of a message concerning the convoy’s course, the wolfpack located the SC.100 convoy of 24 ships supported by Commander Paul R. Heineman’s US Escort Group A3 (US Coast Guard cutters Campbell and Spencer and, among other warships, Canadian corvettes Bittersweet, Mayflower, Rosthern and Trillium, as well as Canadian corvettes Lunenburg and Weyburn and British corvette Nasturtium being transferred for service in 'Torch'). Skilful evasive manoeuvring the allowed the convoy and its escort to shake off the shadowing U-boat on 18 September.

On 19 September, in deteriorating weather, only individual U-boats were able to close with the convoy. In order to find it once again, the 'Pfeil' (i) wolfpack, patrolling to the south-east, was redeployed. U-373 and U-569 missed escort vessels as they sought to approach the convoy on 20 September although Kapitänleutnant Gunter Jahn’s U-596 sank the 5,676-ton British Empire Hartebeeste. On 21 September a storm prevented both sides from offensive action, and on the following day the Germans temporarily broke off the operation. On 23 September, though, favourably located boats were ordered to move toward the RB.1 convoy, which had been located by the 'Vorwärts' wolfpack, while the others followed the SC.100 convoy. Oberleutnant Albracht Brandi’s U-617 sank the 8,882-ton British Athelsultan during the night of 22/23 September and two stragglers (2,432-ton British Tennessee and 3,563-ton Belgian Roumanie) during the following day, and Kapitänleutnant Heinz-Otto Schultze’s U-432 sank the 5,868-ton US Pennmar. Attacks by U-221, U-258 and U-755 failed. On 25 September the pursuit of the SC.100 convoy had finally to be called off.

Of the 'Vorwärts' wolfpack’s 10 boats, which had refuelled from U-461 between 16 and September, U-91, U-96, U-211, U-380, U-404, U-407 and U-584 established a new patrol line in an area to the east of the Newfoundland Bank on 20 September, and here they were joined during the following days by U-260, U-582 and U-619. Between 18 and 24 September the boats attacked: Kapitänleutnant Josef Röther’s U-380 sank the 2,994-ton Norwegian Olaf Fostenes, Kapitänleutnant Karl Hause’s U-211 the 11,237-ton US tanker Esso Williamsburg, Schulte’s U-582 the 2,993-ton Norwegian Vibran, and Oberleutnbant Kurt Makowski’s 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 supported by the British destroyers Vanoc and Veteran, and assumed that the passenger ships were large troop transports. As well as the 'Vorwärts' wolfpack, U-216, U-356, U-410, U-595, U-607, U-617 and U-618 of the 'Pfeil' (i) wolfpack were ordered from the east on completion of the operation against the SC.100 convoy, but as a result of the convoy’s high speed it was difficult for the U-boats to reach 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 Schulz’s U-216 sank the 4,989-ton British Boston and during the evening Oberleutnant Hans-Jürgen Hellriegel’s U-96 torpedoed and damaged the 4,989-ton British New York, which was later torpedoed for a second time by Kapitänleutnant Heinz Walkerling’s U-91 and finally sunk by Veteran. Attacks by U-91, U-356 and U-410 (twice) were unsuccessful. In the morning of 26 September Kapitänleutnant Otto von Bülow’s U-404 sank Veteran and during the evening Makowski’s U-619 sank the straggling 1,547-ton British Yorktown.