Battle of the Atlantic

September 3, 1939 – May 8, 1945 · Atlantic Theater

Phases

1. 11939–41 — The Happy TimeSeptember 1939 – December 1941
2. 21942 – Mar 1943 — Crisis in the Air GapJanuary 1942 – March 1943
3. 3May 1943 – 1945 — Black May and VictoryApril 1943 – May 1945

September 1939 – December 1941

Dönitz’s U-boats open the war’s longest battle — six years for control of Britain’s ocean lifeline. Prien’s U-47 slips into Scapa Flow itself and sinks the battleship Royal Oak at anchor. After the fall of France hands the U-boats Biscay ports 450 miles closer to the convoy lanes, the aces enjoy what their crews call “the Happy Time”: wolfpacks against thinly escorted convoys, a quarter-million tons a month going under.

• ➤U-boat wolfpacks — From the Biscay ports onto the convoy lanes
• ➤HX convoys — Halifax to Liverpool — Britain’s lifeline
• ●Scapa Flow — U-47 sinks HMS Royal Oak at anchor
• ●Western Approaches Command, Liverpool