The Battle of the Atlantic was the longest continuous military campaign of World War II, running

from 1939 right through to the defeat of Nazi Germany in 1945, and was at its height from mid-

1940 through to about the end of 1943.

World War II lasted for a total of 2,075 days. The Battle of the Atlantic lasted for 2,073 of these. It started with the sinking of the passenger liner Athena on the day Britain and France declared war on Germany.

The Allies developed a convoy system where merchant ships were guarded by destroyer escorts. The British developed a system for detecting U-boats that resembled radar. this development gave the Allies the edge in the Battle for the Atlantic. 

German U-boats were sinking ships bound for England with arms.

FDR created a defense zone in the west Atlantic to allow the US Navy to help detect the subs for the Brits.

The campaign pitted the German Navy’s surface raiders and U-boats against Allied convoys from

North America and the South Atlantic to the United Kingdom and Russia, protected mainly by the British and Canadian navies and air forces, later aided by United States ships and aircraft.

• The German plan was to launch over 100 U-The German plan was to launch over 100 U-Boats.Boats.

• Only a couple of dozen were built and Only a couple of dozen were built and launched.launched.

• The allies always assumed there were more The allies always assumed there were more than there were.than there were.

• With the use of SONAR, the U-Boat’s With the use of SONAR, the U-Boat’s advantages were neutralized.advantages were neutralized.

The British and their allies gradually gained the upper hand, driving the German surface raiders from the ocean by the middle of 1941 and decisively defeating the U-boats in a series of convoy battles between March and May 1943

The agreement between FDR and Churchill as to what the world would be like after WW II would like.

FDR promised Churchill he would “force an incident” to get US in the war!