'Rösing' was the U-boat first wolfpack operation in the Atlantic off the north-western corner of Spain primarily against the US.3 convoy (12/15 June 1940).

Named for Korvettenkapitän Hans Rudolf Rösing, commander of U-48, this short-lived pack comprised U-29, U-43, U-46, U-48 and U-101, and sank two ships of the SL.34 convoy as well as two independently sailing ships (18,071 tons).

On 22 June U-46 attacked the fleet carrier Ark Royal, on passage to Gibraltar with the battle-cruiser Hood, but torpedo defects meant that the boat obtained no hits. U-43 refuelled at Vigo on 18 June and U-29 at Ferrol on 20 June, in each case from a German tanker, and were thus able to continue their operations until 15 June and 4 July respectively.

During this period Kapitänleutnant Otto Schuhart’s U-29 sank four ships (5,254-ton Greek independent sailer Dimitris, 7,466-ton Greek independent sailer Adamastos, 8,999-ton British Athellaird of the OB.176 convoy, and 4,919-ton Panamanian independent sailer Santa Margarita); Oberleutnant Wolfgang Lüth’s U-43 sank four British ships (8,627-ton Yarraville of the 65X convoy, 13,376-ton Avelona Star of the SL.36 convoy, 3,944-ton independent sailer Aylesbury and 3,509-ton Fellside of the OA.184 convoy); Oberleutnant Engelbert Endrass’s U-46 sank five ships (20,277-ton British armed merchant cruiser Carinthia, 2,155-ton Finnish independent sailer Margareta, 4,223-ton British Barbara Marie of the SL.34 convoy, 5,041-ton British Willowbank of the SL.34 convoy and 3,651-ton Greek independent sailer Elpis) and also damaged the 8,782-ton Athelprince of the OG.33F convoy; Rösing’s U-48 sank eight ships (798-ton British independent sailer Stancor, 4,212-ton British independent sailer Frances Massey, 3,598-ton Greek independent sailer Violando N. Goulandris, 3,164-ton British Baron Loudoun of the HG.34F convoy, 5,681-ton British British Monarch of the HG.34F convoy, and 6,607-ton Norwegian Tudor of the HG.34F convoy) and also damaged the 5,888-ton British independent sailer Eros; and Kapitänleutnant Fritz Frauenheim’s U-101 sank five independent sailers (3,577-ton British Polycard, 5,820-ton Greek Mount Hymettus, 5,250-ton British Earlspark, 3,557-ton Greek Antonis Georgandis, and 13,212-ton British Wellington Star).