'DU' (ii) was a British naval undertaking against installations at Tromsø in German-occupied Norway (16 October 1940).

The elderly fleet carrier Furious launched 11 Fairey Swordfish and three Blackburn Skua single-engined aircraft of the Fleet Air Arm’s Nos 801 and 816 Squadrons to attack oil tanks and the seaplane base, but the aircraft achieved only very limited success.