The wolfpack was a convoy attack tactic employed in the Second World War. It was used principally by the U-boats of the Kriegsmarine during the Battle of the Atlantic, and by the submarines of the United States Navy in the war in the Pacific. The idea of a co-ordinated submarine attack on convoys had been proposed during the First World War but had no success. In the Atlantic during World War II the Germans had considerable successes with their wolfpack attacks, but were ultimately defeated by the defenders. In the Pacific the American submarine force was able to devastate Japan’s merchant marine, though this was not solely due to the wolfpack tactic. Wolfpacks fell out of use during the Cold War as the role of the submarine changed and as convoys became rare.