German U-boat offensive conducted off the U.S. East Coast, in the Caribbean, in the Gulf of Mexico, and off Brazil.

Commander of German U-boats Vizeadmiral (vice admiral) Karl Dönitz welcomed the entry of the United States into the war in December 1941 as an opportunity to widen the U-boat offensive in the Atlantic. In planning Operation PAUKENSCHLAG (DRUMBEAT), Dönitz intended to operate against the United States and into the Caribbean larger Type IX U-boats with greater operational range. He would employ shorter-range Type VII U-boats off Newfoundland and Nova Scotia, which were much closer to his U-boat bases. Dönitz requested 12 Type IX boats from the Naval War Command for the operation but was informed on 10 December that he would have only 6. Although submarine construction had accelerated, there were still too few U-boats available. Bad weather in the Baltic had also disrupted U-boat training, and the Naval War Command insisted on maintaining a large number of U-boats in the Mediterranean to assist Axis operations in North Africa. In the end, Type IX vessel U-128 was not ready at the start of the operation, so Dönitz had less than half the force he had requested.

Operation DRUMBEAT began with only five Type IX U-boats from the Gulf of Saint Lawrence to Cape Hatteras, North Carolina. Seven Type VII U-boats went to Newfoundland and Nova Scotia. All were in place by mid-January 1942, and DRUMBEAT never involved more than a dozen German submarines at any one time. To keep the Americans off balance, a month after DRUMBEAT was launched Dönitz switched its focus to the Caribbean, where several Italian submarines joined operations.

The first victim of DRUMBEAT, the British freighter Cyclops, fell victim to U-123, a Type IX boat, on 12 January 1942. Other sinkings quickly followed. The United States was totally unprepared for the U-boat attacks. Coastal cities were ablaze with lights at night, silhouetting the merchant ships plying the coast and making them easy targets. There were also few escort vessels available, and merchant ships sailed independently in the hundreds because Chief of Naval Operations Ernest King refused to institute a convoy system, believing that an inadequately protected convoy system was worse than none. All this meant that through April 1942, German submarines sank 216 vessels aggregating 1.2 million tons in the North Atlantic, the vast majority of these in waters for which the U.S. Navy was responsible.

This so-called “second happy time” or “the American turkey shoot” for German submarines finally came to an end through a mandatory blackout of coastal U.S. cities, the instigation of convoys and antisubmarine training schools, the relocation of air assets to antisubmarine duties, and the addition of antisubmarine warships. Not only did merchant shipping losses drop off, but increasing numbers of U-boats were sunk.

On 19 July 1942, Dönitz withdrew his last two U-boats from the East Coast of the United States, relocating his submarine assets back to the mid-Atlantic and signaling an end to the campaign. American unpreparedness had come at a high price. Operation DRUMBEAT was arguably Germany’s most successful submarine operation of the entire war, resulting in the sinking of some 3 million tons of shipping. Undoubtedly, Dönitz would have enjoyed even greater success had he been able to employ more U-boats at the offset of the campaign.

References Blair, Clay. Hitler’s U-Boat War. Vol. 1, The Hunters, 1939–1942. New York: Random House, 1996. Gannon, Michael. Operation Drumbeat: The Dramatic True Story of Germany’s First U-Boat Attacks along the American Coast in World War II. New York: Harper and Row, 1990. Morison, Samuel Eliot. History of United States Naval Operations in World War II. Vol. 1, The Battle of the Atlantic, 1941–1943. Boston: Little, Brown, 1949.