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Battle of the Atlantic Timeline

Authored By Dan Alex | Last Updated: 5/5/2014

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

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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 1943 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.


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There are a total of 27 Battle of the Atlantic Timeline Events. Entries are listed below by date of occurrence.

1939
Sunday
September 3rd

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.

1939
Tuesday
September 5th

The Bosnia becomes the first merchantman to be sunk by the German U-boats.

1939
Wednesday
September 6th

Thirty-six Allied ships set out across the Atlantic in the first coordinated convoy crossing attempt.

1940
Monday
January 1st

Only 21 operational boats make up the German U-boat fleet at this time.

1940
Saturday
July 6th

German ships begin operating out of captured bases along the French coast.

1940
Saturday
August 17th

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.

1940
Friday
September 20th

Massive convoys breed equal massive measures - German U-boats begin operating in 20-strong "Wolf Packs" with coordinated attacks.

1940
Friday
October 18th - October 19th

An attack on two Allied convoys yields 36 sunken ships by the attacking German U-boats.

1941
Tuesday
March 11th

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.

1941
Thursday
April 10th

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.

1941
Friday
May 9th

HMS Bulldog acquires the first Enigma code machine during the capture of the U-110. British codebreakers set to work on deciphering the device.

1941
Tuesday
May 27th

The first escorted convoy - HX129 - crosses the Atlantic.

1942
Thursday
January 1st

The German U-boat fleet now numbers some 331 operational vessels.

1942
Thursday
January 1st - March 1st

Off the east coast of the United States, some 216 vessels fall prey to the German U-boat scourge in this span.

1942
Thursday
May 14th

The convoy system is formally adopted by the United States in an effort to protect its merchant shipping in the Atlantic.

1942
Monday
June 1st - June 30th

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.

1942
Sunday
July 19th

German U-boats off the eastern coast of the US are relocated to better assault the merchant fleets streaming across the Atlantic.

1943
Thursday
January 14th

U-boat bases at Cherbourg and Lorient are targeted by the Royal Air Force.

1943
Monday
February 1st

A Presidential directive calls for some 250 American aircraft to begin offensive actions in the Atlantic.

1943
Saturday
May 1st

Allied aircraft are fitted with U-boat detecting radar systems.

1943
Saturday
May 1st - May 31st

By the end of May, 43 U-boats are sunk to just 34 merchant vessels.

1943
Wednesday
May 19th

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.

1943
Monday
May 24th

Due to dwindling results, German Admiral Karl Donitz calls back his U-boats from operations in the Atlantic.

1943
Tuesday
June 1st

The German U-boats are unleashed once more, this time operating in substantially smaller groups.

1943
Sunday
June 6th

The Allied D-Day landings in the North of France eventually render the French-German U-boat bases inoperable.

1945
Sunday
April 1st - April 30th

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.

1945
Tuesday
May 1st

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.