The outcome of WWII depended heavily on maintaining a steady flow of vital supplies from the US and Canada to the war-torn Europe across the Atlantic Ocean. Therefore, for six long years, thousands of sailors, airmen and hundreds of warships, merchant ships and aircraft waged the greatest naval battle in history against the wolf packs of the German U-boats. The Battle of the Atlantic was the longest, most complex and certainly one of the most important battles to tip the scales of WWII.