'Delphin' (ii) was a U-boat wolfpack operation in the Atlantic Ocean against the TM.1 and UGS.4 convoys (26 December 1942/14 February 1943).

The wolfpack comprised U-87, U-107, U-125, U-202, U-258, U-264, U-381, U-436, U-442, U-463, U-511, U-514, U-522, U-558, U-571, U-575 and U-620. For the loss of Fregattenkapitän Hans-Joachim Hesse’s U-442 and Kapitänleutnant Heinz Stein’s U-620, the boats of this wolfpack sank 11 ships (79,680 tons) including one 6,983-ton ship which had been damaged earlier in the operation.

On 28 December the TM.1 convoy of nine tankers supported by Commander R. C. Boyle’s British Escort Group B5 (destroyer Havelock and corvettes Godetia, Pimpernel and Saxifrage) departed Trinidad. Having sailed late in company with Godetia, two of the tankers were sighted on 29 December by U-124, but the boat’s several attempts to attack were prevented by the corvette and a US Consolidated Catalina twin-engined flying boat. As U-124 made no sighting report indicating the presence of a convoy, however, the German submarine headquarters at this time issued no concentration or attack order to other U-boats in the area.

On 3 January, though, U-514 reported the convoy about 1,265 miles (2035 km) to the north-east of Trinidad and apparently routed toward Gibraltar. Kapitänleutnant Hans-Jürgen Auffermann’s U-514 was allowed to attack and then torpedoed the 8,093-ton British tanker British Vigilance, whose wreck was sunk on 24 January by Kapitänleutnant Jürgen Nissen’s returning U-105, which also sank a 5,106-ton independent sailer.

Vizeadmiral Karl Dönitz, commander of the U-boat arm, instructed U-514 to maintain contact and directed U-105 westward toward the convoy. The 'Delphin' (ii) wolfpack, after looking fruitlessly for the GUS.2 convoy (43 ships supported by Task Force 37 and which had first been reported by U-182 on 29 December) was ordered to form a patrol line across the predicted course of the convoy for 7 January.

Because it did not obey a rerouting order that reflected British radio location of the U-boat concentration, the TM.1 convoy steamed straight into the path of the 'Delphin' (ii) wolfpack and was reported to U-boat headquarters on 8 January by U-381. Making the first attack, Kapitänleutnant Günther Seibicke’s U-436 sank the 8,309-ton Norwegian Albert L. Ellsworth and the 6,394-ton British Oltenia II, but was also depth-charged and damaged by the destroyer Havelock. U-571 and Kapitänleutnant Günther Heydemann’s U-575 were driven off by Pimpernel and Godetia respectively, but the U-575 made a new attack during the morning of 9 January, torpedoing the 6,833-ton Norwegian Minister Wedel and 10,034-ton Panamanian Norvik. Soon after this, Hesse’s U-442 torpedoed the 9,807-ton British Empire Lytton. During the daylight hours the escorts managed to defeat the effort of U-181, and U-134 both failed in an attack on the Norwegian Vanja and was also depth-charged and damaged by Godetia. U-381 was attacked by Harvester and Pimpernel, and throughout this period U-620 maintained contact.

In the evening of 9 January Kapitänleutnant Herbert Schneider’s U-522 despatched the damaged Minister Wedel and Norvik, and Hesse’s U-442 and Seibicke’s U-436 sank the wrecks of Empire Lytton and Albert L. Ellsworth respectively. Kapitänleutnant Fritz Schneewind’s U-511 sank the 5,004-ton William Wilberforce, a British independent sailer, in the same general area. During the evening of 10 January U-620 missed the main convoy but Schneider’s U-522 torpedoed the 6,983-ton British British Dominion, which was later sunk by Stein’s U-620. U-571 launched torpedoes at the two remaining tankers, Vanja and the Dutch Cliona, in the evenings of 10 and 11 January, respectively, but the tankers spotted and avoided the torpedoes, as well as those of U-511 on the morning of the following day.

The escort was strengthened at this juncture by the arrival of the destroyer Quentin and corvettes Penstemon and Samphire from Gibraltar, and also by aircraft. The two remaining tankers reached Gibraltar on 14 January. On 7 February U-521 spotted the small Gibr.2 coastal convoy of three freighters and four anti-submarine trawlers, together with air cover, and sank the trawler British Bredon. U-202, U-558, U-87, U-264 and U-258 of the 'Delphin' (ii) wolfpack were ordered to the scene, but could not arrive before the destroyer Haydon and the US submarine chasers PC-471 and PC-474 supplemented the convoy’s escort on 9 February. On the following day U-108 was damaged by a Catalina flying boat of the RAF’s No. 202 Squadron, but was able to continue her patrol.

The remaining boats of the 'Delphin' (ii) wolfpack operated to the west of Cape St Vincent, where Hesse’s U-442 and Stein’s U-620 were sunk by the air escort in an operation against the KMS.9 convoy, whose location had been reported by air reconnaissance: U-442 fell victim on 12 February to a Lockheed Hudson twin-engined patrol bomber of the RAF’s No. 48 Squadron and U-620 succumbed two days later to a Catalina of the RAF’s No. 202 Squadron which also inflicted damage on U-381.