Battle of the Atlantic - WW2 Timeline (September 3rd, 1939 - May 7th, 1945)

Control of the Atlantic shipping lanes was key to both an Allied and an Axis victory - luckily for the Allies, victory smiled upon them.

The Battle of the Atlantic is one of the most overlooked battlegrounds of World War 2 but it proved no less important for control of vital shipping lanes between North America and Europe.The German U-boat scourge was one of the more deadlier components of the German war machine, a component utilized in World War 1 as well. The U-boat became the greatest threat to merchantmen traversing the long, open causeways of the Atlantic Ocean for most of the war.

Germany understood the important of resupply to the island nation of Great Britain. If Britain were to lose its importing, she would under intense pressure and unable to keep fresh its fighting forces through food, clothing, supplies, ammunition and automotive parts. Equally, British Prime Minister Winston Churchill understood the vital nature of the lanes between the UK and its American allies for The New World - it seems - would play an important role in keeping The Old World afloat.

Similarly, the Soviet Union would come to depend on the Atlantic shipping lanes for the vital supplies and various war-making implements such as fighters and tanks incoming from America - this of course after Hitler's decision to invade the Soviet Union through "Operation Barbarossa" in June of 1941.

As it stood, German Admiral Karl Donitz took command of the of the U-boat fleet in 1935. He fully took to heart the value of Atlantic control and forged his fleet into a cohesive fighting force bent on annihilating the support structure that resupplied Europe. His directives included the tactic known as "Wolf Packs" in which multiple German submarines would engage an enemy ship or convoy in concert, causing all sorts of calculated havoc and - ultimately - victory. Additionally, merchant ships of the time were unarmed, making them rather juicy targets to those submarines lying in wait.

However, German blunders prevailed in developing a substantial undersea force for Donitz by September of 1939. Authorities placed an emphasis on the construction of surface vessels instead, forcing the U-boat fleet to number just 56 completed ships instead of the 300 or so envisioned by this time. Additionally, only about 22 of these submarines were actually built for the rough life of deep ocean diving and combat - the rest being nothing more than coastal patrol vessels with limited capability.

The British liner Athenia became the first U-boat casualty, en route from Glasgow to Montreal, and resulted in the loss of 112 souls on September 3rd, 1939. Two days later, the Bosnia became the first merchant ship to fall to the U-boats. The "convoy system" was then devised by the Allies and put into effect the next day. Merchant vessels were also now armed for the task and given orders to ram German warships if the scenario presented itself. These decisions, in Donitz's eyes, allowed for an " open-attack" policy on any Allied merchant vessel operating in the Atlantic.

Though still operating in limited numbers, the U-boats made their presence felt. Targets of opportunity initially became single ships and then graduated to unprotected convoys. As the plunder grew, so too did the German's area of operations west of Ireland.

1940 and the Fall of France added all-new origination ports for the German Kriegsmarine. Now U-boats could operate from these locations closer to the Atlantic Theater. Additionally, the German Luftwaffe was upgraded with longer-ranged maritime reconnaissance aircraft that could not only mark targets for the U-boats but also tackle them through their own anti-ship measures. U-boats now had unprecedented reach throughout the vast ocean lanes, forcing the Allies to restructure their travel plans and put old battleships into service for interim protection. The signing of the Lend-Lease Act by the United States allowed for military assistance to Britain and the Soviet Union, helping matters somewhat. Despite this, U-boat "aces" were being born and thousands of tons of goods were lost to the ocean.

The Allies turned to ingenuity and developed several systems of note. Powerful searchlights, anti-ship patrol aircraft on escort carriers and radio transmission interceptors all began working against the U-boat fleet. While 1941 saw nearly 500 Allied ships and over 2.4 million tons of goods lost, 1942 was even worse with over 1,000 ships and nearly 5.5 million tons of goods lost.

However, by March of 1943, the golden age of the German U-boat - and any advantage they held - was undone. Allied tactics improved thanks to technology, experience and execution. U-boats were increasingly targeted as were their all-important bases of origination. The RAF succeeded in disrupting such operations along the coast of France and the successful June 1944 D-Day invasions removed these German Navy bases from contention altogether. The commission-to-loss rate of the U-boat fleet became unsupportable - with 98 new boats placed online to try and replace the 123 or so lost.

Despite the fleet numbering some 400-strong, the U-boat scourge was all but over. As Allied forces made headway throughout Africa, Italy and France, the tide had turned on the Germans in more ways than one. The U-boat capacity was one such casualty for the Germans and a major (as well as critical) victory for the Allied cause.

Arguably the most important battlefront of World War 2 was now contained in favor of the Allies.

There are a total of (27) Battle of the Atlantic - WW2 Timeline (September 3rd, 1939 - May 7th, 1945) events in the database. Entries are listed below by date-of-occurrence ascending (first-to-last). Other leading and trailing events may also be included for perspective.

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.

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