Battle of the Atlantic: 1939-1943

The "Atlantic Lifeline" was the shipping route between the United States and England, the only means by which Britain could survive Hitler's increasing grip on Europe. Winston Churchill coined the term 'Battle of the Atlantic' and saw that struggle, the longest campaign of World War II, as the greatest peril facing England.

Coast Guardsman outfitted for the winter convoy battles with Depth Charge Projector Mark 6, Mod 1 (K-Gun) used to deploy 300 pound cylindrical Mk 6 depth charges in a wide pattern around the escort vessel
Coast Guardsman outfitted for the winter convoy battles with Depth Charge Projector Mark 6, Mod 1 (K-Gun) used to deploy 300 pound cylindrical Mk 6 depth charges in a wide pattern around the escort vessel.

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Early Phase of Battle of the Atlantic

In September 1939, when Germany attacked Poland and World War II began, Admiral Karl Dönitz had 57 Unterseebooten (submarines). Early that month, the British liner Athenia became the first sinking by a sub in the war, followed in a few days by the Bosnia, the first cargo ship sunk. At the same time, the Allies restored the WW I practice of massing ships into more easily defended convoys.

In June 1940 Germany conquered both Norway and France, giving them bases on the Atlantic which increased the range of the U-boats and allowed Focke-Wulf FW200 'Kondor' long-range aircraft to provide reconnaissance and directly attack Allied shipping. The Royal Navy was helped in their fight against this menace by the arrival of 50 old American destroyers, but the situation steadily worsened as the fight against submarines took second priority to defense of the British Isles from invasion in the Battle of Britain. U-boats, supplemented by aircraft, surface ships, and mines sank 3 million tons of Allied shipping between June 1940 and the end of the year. U-boat crews dubbed the period July-October 1940 the "Glückliche Zeit (Happy Time)".

The U.S. Joins the Battle of the Atlantic

At the end of 1940, Admiral Dönitz introduced the 'wolfpack' tactic, grouping his submarines and attacking at night on the surface, greatly reducing the effectiveness of the British ASDIC sonar. The bleak situation prompted a greater response from the United States, sympathetic to England but not yet officially in the war. In May 1941 the U.S. Navy took over escort duties in the western Atlantic. In July, a contingent of Marines joined British Commonwealth troops occupying Iceland, strategically located for the air and naval control of the North Atlantic lifeline. The Royal Canadian Navy also increased its role by building many small escort warships ("Corvettes") and joining the convoys.

As the U.S. increased its role it inevitably became involved in the shooting war with Germany. On 31 October 1941 (Halloween) an American warship, the destroyer USS Reuben James (DD-245), was torpedoed and sunk by the submarine U-562 while escorting British ships, the first U.S. warship lost to hostile action in World War II. By the time of Pearl Harbor (7 December 1941) Germany and the U.S. were effectively at war in the Atlantic.

Peak of the Battle of the Atlantic: January 1942- May 1943

A boarding party from USS Spencer (WPG-36) pulls near the sinking U-175.  Lt. Ross P. Bullard climbed aboard U-175 before it sank, the first American serviceman to board an enemy warship 'underway at sea' since the 19th century. 17 April 1943
U-175 sinking after successful attack by USS Spencer (WPG-36) 17 April 1943. The boarding party included Lt. Ross P. Bullard who climbed aboard U-175 before it sank, the first American serviceman to board an enemy warship "underway at sea" since the 19th century.

Allied success in breaking the German Enigma code was an important help early in the war, but changes to the naval Enigma code at the beginning of 1942 stopped the flow of intelligence, bringing an increase in the loss of Allied ships. Furthermore, the U.S. entered the war unprepared and did not initially effectively protect its ships. As a result, a small number of U-boats in the North American and Caribbean coastal waters sank nearly 500 Allied ships in the first half of 1942. (January-July 1942 was the second "Glückliche Zeit" for U-boat crews ). By July 1942, Dönitz had 300 U-boats, with 140 operational at once, hunting in wolf packs and sinking shipping at an annual rate of seven million tons, five times the rate of British replacement capacity. U-boats operated almost unopposed in the "Mid-Atlantic Gap" -- the area that could not be reached by aircraft from Canada or Britain -- supplied by special vessels known as "milch cow"' carrying additional torpedoes and food. German naval intelligence broke British codes and directed submarines to intercept convoys.

At the beginning of 1943 Döntiz, now commander of the Kriegsmarine (German Navy), had 200 operational U-boats and British supplies of oil and other essentials were very low. But the tide was about to turn as mass production of Liberty Ships in U.S. shipyards replaced more than the U-boats could sink. The British, Americans and Canadians all added warships and cargo vessels at an astounding rate while the effectiveness of radar and other defenses against U-boats improved greatly. Long range aircraft and escort carriers eliminated the Mid-Atlantic Gap.

By April 1943 shipping losses to U-boats had shrunk to minimal levels while Allied sinkings of German submarines escalated, with 45 destroyed in the months of April and May. Döntiz recognized that the U-boat was no longer an effective weapon and called off the Battle of the Atlantic on 23 May 1943.

In May 1945, in the closing days of the war in Europe, Döntiz was designated by Hitler as his successor, a largely meaningless gesture. Döntiz was captured by the Allies and tried at Nuremberg in 1946. He was sentenced to 20 years in prison.

Losses in the Battle of the Atlantic

The Battle of the Atlantic was the longest campaign of World War Two, with heavy losses on both sides. Between 75,000 and 85,000 Allied seamen were killed while 19,000 U-boat crew members are estimated to have died in the Battle of the Atlantic. For the Allies it was a price that had to be paid -- if the U-boat stranglehold had not been broken, England could have fallen and the Allied counterattacks in North Africa and Europe could not have been mounted.

Recommended Book about the Battle of the Atlantic

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