 While the attack on Kaafjord was being conducted , the commander of the German submarines in the Norwegian sea ordered Group Trutz to take up new positions to the south @-@ east of Jan Mayen and intercept the British ships as they returned to Scapa Flow . The Admiralty had anticipated this redeployment , and maritime patrol aircraft from No. 18 Group RAF were directed to sweep the Home Fleet 's route back to its base . 
