'Cosmic' was the British contingency disposition of the naval forces required to combat any movement to the south by the German battleship Tirpitz from the Altafjord in the north of German-occupied Norway (13/25 March 1944).
In the first part of the month 'Ultra' decrypts had suggested that the Germans might be planning to transfer Tirpitz to Germany for repairs, and on 13 March a message about the northward move of German destroyers persuaded the British that the German plan was being implemented. British submarine patrols off Norway were therefore strengthened. On 16 March the Free Dutch Zwaardvis departed for the Gimsöströmmen and Syrtis and Taku for the Kya area; Satyr and Vox were ordered to Stadlandet, the Free Norwegian Ula to Bredsund, and the British Trusty and Vivid to Skudesnes. On 18 March Safari, Sturdy, Terrapin, Truant, Una, Unbending, Unbroken and the Free Dutch Zeehond left Lerwick for Norwegian waters.
Then on 20 March it started to become clear that the Germans might not be moving Tirpitz, so Safari, Truant, Una, Unbroken, Vivid, Zeehond and Zwaardvis were ordered back to base. Syrtis was redirected to Bodø, where on 22 March it sank the 214-ton Norwegian Narvik before being lost to a mine six days later. Ula was despatched against the liner Monte Rosa, which was being moved north as an accommodation ship for repair work on Tirpitz, but was not able to effect an interception, and on 21 March missed a convoy. Off Namsos, Taku missed a motor vessel on 24 March, but on the same day Satyr sank the 340-ton Norwegian Nord Norge, and Terrapin torpedoed and damaged the 6,256-ton tanker Worth and the 8,186-ton catapult ship Schwabenland, both of which had to be run aground in the Flekkefjord to prevent them from sinking.