Although Churchill believed that the involvement of the United States in the war had tilted the odds of victory toward the Allies, he knew that Britain needed positive engagements to maintain morale and buy time for the United States to spool up to a war footing.
By January 1942, the German U-Boat fleet had grown to nearly two hundred vessels with roughly half operational at any moment. To gain dominance over the Atlantic shipping lanes that supplied Britain and Russia, Kriegsmarine Admiral and former WWI U-Boat commander, Karl Dönitz needed either more submarines or stronger engagement from the German surface fleet, particularly the newly operational battleship Tirpitz.