Day-by-Day Timeline of Events
Sunday, September 3rd, 1939
Athenia, a British passenger liner originating from Glasgow and traveling to Montreal, is targeted and sunk by German U-boat U-30 resulting the loss of 112 people. Athenia becomes the first naval casualty of the U-boat scourge in the Atlantic.
Tuesday, September 5th, 1939
The Bosnia becomes the first merchantman to be sunk by the German U-boats.
Wednesday, September 6th, 1939
Thirty-six Allied ships set out across the Atlantic in the first coordinated convoy crossing attempt.
Monday, January 1st, 1940
Only 21 operational boats make up the German U-boat fleet at this time.
Saturday, July 6th, 1940
German ships begin operating out of captured bases along the French coast.
Saturday, August 17th, 1940
German U-boats are given the green light to attack any and all merchant vessels - whether armed or not - in an attempt to stranglehold the British mainland into submission.
Friday, September 20th, 1940
Massive convoys breed equal massive measures - German U-boats begin operating in 20-strong "Wolf Packs" with coordinated attacks.
Friday, October 18th - October 19th, 1940
An attack on two Allied convoys yields 36 sunken ships by the attacking German U-boats.
Tuesday, March 11th, 1941
The Lend-Lease Bill is signed into law by American President Franklin Roosevelt allowing the United States the unrestricted ability to help supply the Allies in their fight against the Axis.
Thursday, April 10th, 1941
The first US combat action against Germany occurs - this being the USS Niblack destroyer firing on a marauding German U-boat violating the US security zone.
Friday, May 9th, 1941
HMS Bulldog acquires the first Enigma code machine during the capture of the U-110. British codebreakers set to work on deciphering the device.
Tuesday, May 27th, 1941
The first escorted convoy - HX129 - crosses the Atlantic.
Thursday, January 1st, 1942
The German U-boat fleet now numbers some 331 operational vessels.
Thursday, January 1st - March 1st, 1942
Off the east coast of the United States, some 216 vessels fall prey to the German U-boat scourge in this span.
Thursday, May 14th, 1942
The convoy system is formally adopted by the United States in an effort to protect its merchant shipping in the Atlantic.
Monday, June 1st - June 30th, 1942
June of 1942 marks the single worst month of Allied shipping losses, totaling some 834,000 tons of goods at the bottom of the Atlantic Ocean.
Sunday, July 19th, 1942
German U-boats off the eastern coast of the US are relocated to better assault the merchant fleets streaming across the Atlantic.
Thursday, January 14th, 1943
U-boat bases at Cherbourg and Lorient are targeted by the Royal Air Force.
Monday, February 1st, 1943
A Presidential directive calls for some 250 American aircraft to begin offensive actions in the Atlantic.
Saturday, May 1st, 1943
Allied aircraft are fitted with U-boat detecting radar systems.
Saturday, May 1st - May 31st, 1943
By the end of May, 43 U-boats are sunk to just 34 merchant vessels.
Wednesday, May 19th, 1943
Some 33 U-boats assail an Allied convoy. However, the streamlined Allied response nets zero ship losses and fatalities. The U-boats come up empty.
Monday, May 24th, 1943
Due to dwindling results, German Admiral Karl Donitz calls back his U-boats from operations in the Atlantic.
Tuesday, June 1st, 1943
The German U-boats are unleashed once more, this time operating in substantially smaller groups.
Sunday, June 6th, 1943
The Allied D-Day landings in the North of France eventually render the French-German U-boat bases inoperable.
Sunday, April 1st - April 30th, 1945
The USN is credited with sinking four German U-boats in what turns out to be the last recorded combat actions in the Atlantic Theater of War.
Tuesday, May 1st, 1945
By May of 1945, the U-boat scourge in the Atlantic is over, completing one of the more important battles in all of World War 2.