The battle itself was a fierce battle between ships, convoys, airplanes, and u-boats. It lasted the entire battle and was fought on almost the entire span of the Atlantic Ocean. It began immediately after Britain and France declared war on Germany. In the beginning of the war Germany was the main contender for the win. They were making fierce offensive moves. They were attacking British, French and even American convoys, ships without protection and everything they thought was a ship of the Allies. They used u-boats (boats underwater/submarines) and planes to attack the ships from above and below. Around halfway through the war the balance began to tip in the Allied Power's favor. They were getting new battleships from America and Canada was pitching in by protecting Allied ships during journeys. About a year later the balance tipped again, this time in favor of the Germans. New submarines were being manufactured and put to work causing much danger for the Allies. In about another year the balance tipped back in favor of the Allies. The Allies now had weapons that could shoot down submarines and u-boats underneath their ships. After just a short amount of time submarines and u-boats became completely useless. This cost Germany the battle. Grand Admiral Carl Doenitz was the commander in the German navy who finally surrendered the battle in 1945, giving the Allies a win.