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Battle of the Atlantic: An Overview 

The Battle of the Atlantic was one of the most important fronts in World War II. In September 1939, Germany immediately sought to capitalize on Britain’s dependence on imports of food and raw materials.  After the Wehrmacht attacked it in June 1941, the U.S.S.R repeatedly asserted its dire need for imported equipment and supplies. Meanwhile the Allies had to wrestle control of the seas to support several “second” fronts, first in North Africa, then Italy, and finally western Europe. The U.S., British, and Canadian navies worked together to overcome terrible losses inflicted by German U-boats and Luftwaffe bombers, but the issue remained in doubt until 1943.

From the U.S. perspective, the struggle moved through three phases. When the war began in Europe, the United States maintained neutrality while also increasing the readiness of its fleet. After signing the “Two-Ocean Navy” legislation in the summer of 1940, President Franklin Roosevelt next pushed to assist Britain.  In August 1940, he arranged a “loan” of older destroyers in exchange for the use of British bases in the Western Hemisphere. The following March, he secured passage of the Lend-Lease Act to enable a cash-starved Britain to receive equipment and supplies and then pay for them later. In May and July 1941, U.S. forces occupied bases in Greenland and then Iceland.

During this early period, Germany had aimed to avoid directly engaging American naval forces, but the two countries drifted closer to war in the months preceding Pearl Harbor. On 4 September, a German submarine, after being attacked by a British plane, fired torpedoes at Greer (DD-145) in waters south of Iceland. Greer responded with 19 depth charges. Neither opponent scored a hit, but the incident freed President Roosevelt to authorize Navy crews to fire at German U-boats upon sighting. Escorts began accompanying merchantmen up to a mid-ocean meeting point, where British ships took over the convoy responsibilities.1 On 31 October, U-552 torpedoed and sank Reuben James (DD-245) , the first U.S. Navy ship lost to enemy action in World War II.2

Although it had improved its readiness before formally being at war, the Navy was inadequately prepared for the ferocity of the German assault it faced in the second phase of the Battle of the Atlantic. U-boats announced their presence off the eastern coast of the United States by sinking the steamer Cyclops on 12 January 1942. The enemy’s Operation Drumbeat continued for months as German submarines enjoyed a “happy time” hunting tankers and merchantmen, which frequently sailed independently and at night silhouetted themselves in front of coastal city lights. The Navy had too few destroyers and subchasers to screen the coast while also escorting merchantmen or troop ships in the Atlantic. Inadequate numbers of aircraft, whether from the Navy or the Army Air Corps, also limited patrolling.3 From January through April, German submarines sank over 80 merchantmen off the East Coast and 55 in the region north of Bermuda. By May, merchantmen began sailing in convoys as the Navy increased the number of ships and aircraft and improved their crews’ training, which prompted U-boats to shift to easier targets moving through the Gulf of Mexico and the Caribbean.

American escort forces delivered 100,000 troops and their equipment for Operation Torch in North Africa in the fall of 1942, but Germany continued to reposition its boats and hunt effectively in more weakly protected areas until the contest’s third phase began in May 1943. By then, British and Canadian forces had begun to provide effective defenses for the North Atlantic convoys and Admiral Ernest J. King established himself as commander of Tenth Fleet. Charged with directing the Americans’ antisubmarine efforts in the Atlantic, the new organization had no assigned ships but employed innovative scientific efforts to maximize the effectiveness of offensive and defensive techniques. Very long range scout and bomber aircraft using new radar helped close “air gaps” where submarines had enjoyed freer rein. Accompanying the convoys, increasing numbers of escort carriers and destroyers now directed a deadly combination of air and sea-delivered munitions at the submarines. Meanwhile, British interception of German message traffic provided valuable intelligence about U-boat locations. U.S. industrial production of naval vessels and “Liberty” merchantmen also began to make its weight felt.4

After much blood and treasure had sunk in frigid waters since the war’s beginning, the tide had turned by the middle of 1943. German U-boat crews bravely fought on, but at a distinct disadvantage that meant Allied planners could more confidently plan and execute their land campaigns in Europe. The Allies had prevailed and showed innovation and tenacity in the process. But success came after the learning of relearning of old lessons.

As in World War I, some naval leaders were slow to react to the threat posed by German submarines. Sending merchantmen in escorted convoys had proved to be vitally important in 1917–18, but in early 1942 American officials waited months before insisting on this tactic. Conflicts arose over whether to prioritize the “defensive” effort of protecting the commercial vessels or the “offensive” option of attacking submarines, although both approaches served the same strategic goal. The Battle of the Atlantic also demonstrated a key relationship between technology and training.  Advances such as sonar and radar could provide the Navy’s escorts an advantage over the submarines, but they did so only after crews received adequate time to train with them. Finally, the beginning of World War II also revealed that such early periods in conflict often display a level of unpreparedness that becomes palpable only after the fact. 

                                                   —Jon Middaugh, NHHC Histories and Archives Division, January 2017


1 Naval History and Heritage Command, Dictionary of American Naval Fighting Ships, accessed 25 January 2017.          

2 Naval History and Heritage Command, Dictionary of American Naval Fighting Ships, accessed 25 January 2017.

3 Robert W. Love, Jr., “The U.S. Navy and Operation Roll of the Drums, 1942,” in Timothy J. Runyan and Jan M. Copes, eds., To Die Gallantly: The Battle of the Atlantic (Boulder, CO: Westview Press, 1994), 95–120.

4 Jonathan Dimbleby, The Battle of the Atlantic: How the Allies Won the War (New York: Oxford University Press, 2016); Marc Milner, “Squaring Some of the Corners: The Royal Canadian Navy and the Pattern of the Atlantic War,” in Runyan and Copes, 121–136; and Samuel Eliot Morison, History of United States Naval Operations in World War II Vol. X: The Atlantic Battle Won, May 1943–May 1945, (Boston: Little Brown and Company, 1956), 1–84

5 William S. Sims, The Victory at Sea (Garden City, NY: Doubleday, 1921), 3–49; William N. Still, Jr. Crisis at Sea:  The United States Navy in European Waters in World War I, (Gainesville, FL:  University of Florida Press, 2006), 445–77; Dimbleby, 381–86; Dean C. Allard, “Introduction: An American Assessment,” Runyan and Copes, xvi–xxvi.




Dimbleby, Jonathan. The Battle of the Atlantic: How the Allies Won the War. New York: Oxford University Press, 2016.

Gannon, Michael. Operation Drumbeat: The Dramatic True Story of Germany’s First U-Boat Attacks Along the American Coast in World II. New York: Harper & Row Publishers, 1990.

Howarth, Stephen, and Derek Law, eds. The Battle of the Atlantic, 1939-1945: The 50th Anniversary

International Naval Conference. Annapolis, MD: U.S. Naval Institute Press, 1994.

Morrison, Samuel Eliot, History of United States Naval Operations in World War II Vol. I: The Battle of the Atlantic, September 1939–May 1945. Boston: Little Brown and Company, 1954.

———History of United States Naval Operations in World War II Vol. X: The Atlantic Battle Won, May 1943–May 1945. Boston: Little Brown and Company, 1956.

Runyan, Timothy J., and Jan M. Copes, eds., To Die Gallantly: The Battle of the Atlantic. Boulder, CO: Westview Press, 1994.

Van der Vat, Dan. The Atlantic Campaign: World War II’s Great Struggle at Sea. New York: Harper and Row, 1988.

Published: Fri Jun 16 12:30:08 EDT 2017