'EU' was an Allied naval undertaking in which the US heavy cruiser Tuscaloosa and three destroyers steamed from Scapa Flow in the Orkney islands group to the northern USSR to deliver ground personnel, supplies and torpedoes for the two Handley Page Hampden twin-engined torpedo bomber squadrons which Air Chief Marshal Sir Philip Joubert de la Ferté's RAF Coastal Command was about to transfer to the northern USSR in 'EM' (ii), and then return with the survivors of the PQ.17 convoy disaster (13/23 August 1942).

Supported by the US destroyers Rodman and Emmons and, from 19 August at the Seyðisfjörður in eastern Iceland, the British Onslaught, Tuscaloosa sailed to Murmansk. The ships were met off the Kola inlet by the British destroyers Marne and Martin and the Soviet destroyers Gremyashchy and Sokrushitelny. After unloading, Tuscaloosa, Emmons and Rodman departed Murmansk to return to Scapa Flow on 24 August, arriving with the survivors of the PQ.17 convoy on 28 August.

Marne, Martin and Onslaught were detached to make a sortie to the Arctic coast of German-occupied Norway where, on 28 August, they encountered and sank the auxiliary minelayer Ulm off Bjørnøya.