- It was the longest continuous military campaign of World War II
- It was at its height from mid-1940 through to the end of 1943
- The Battle of the Atlantic pitted you-boats and other warships of the German Navy against Allied convoys
- The Germans were joined by submarines of the Italian Royal Navy after Italy entered the war on June 10, 1940
- Tactical advantage switched back and forth over the six years as new weapons, tactics and counter-measures were developed by both sides
- The British and their allies gradually gained the upper hand, driving the German surface raiders from the ocean by the end of 1942 and decisively defeating the you-boats in a series of convoy battles between March and May 1943
- New German submarines arrived in 1945, but they were too late to affect the course of the war
