This was a U-boat wolfpack operation in the Atlantic against the HX.218 convoy (9/15 December 1942).
The wolfpack comprised U-373, U-445 and U-663, and neither lost any of its own number nor sank any ship.
The wolfpack was deployed to the south of Greenland in the hope of catching and savaging the HX.218 convoy of 54 merchant vessels, supported by the British Escort Group B3. U-373 spotted the convoy on 13 December but was driven off after four hours by the approach of two destroyers. U-663 was later depth-charged by a destroyer and damaged severely enough to have to return to base. At this time further efforts to attack the eastbound convoy devolved onto the 'Ungestüm' wolfpack, which was located farther to the east in the area to the south of Iceland.