Operation Nordseetour was the first Atlantic sortie of the German heavy cruiser Admiral Hipper during December, 1940.
The first attack, on troop convoy WS-5A, took place in December 1940. Although one of the escorting British cruisers, HMS Berwick, was heavily damaged, the impact on the convoy was limited to damage to two merchantman. Engine problems and low fuel stores obliged Admiral Hipper to return to Brest. En route, she encountered and sank the freighter Jumna. Repairs took about a month to complete.
References
Operation Nordseetour Wikipedia(Text) CC BY-SA