Answer: The battle of the Atlantic was the longest battles fought in World War Two. It began immediately after the british declared war on Germany in 1939. During those six years, thousands of ships were sunk and ten of thousands men were killed. The battle pitted allied merchant and supply ships along with their escorts against german submarines and aircraft. The outcome of the battle of atlantic depended on the destroyers, which had torpedos, and were fast. It ended with germany surrendering in, May, 1945.