The Second Happy Time Ends: U-boats Retreat from the American Coast (July 19, 1942)
For six catastrophic months in early 1942, German U-boats prowled the shores of the United States virtually unopposed, sinking hundreds of merchant ships within sight of American beaches. This slaughter, which German submariners nicknamed the 'Second Happy Time,' finally ended on July 19, 1942, when Admiral Karl Dönitz withdrew his U-boats from North American waters as an expanding convoy system made the coast too dangerous to hunt.
Operation Drumbeat Opens a New Front
When Adolf Hitler and Benito Mussolini declared war on the United States on December 11, 1941, following Japan's attack on Pearl Harbor, Dönitz saw an opportunity. He launched Operation Paukenschlag, or 'Drumbeat,' sending just five long-range Type IX U-boats across the Atlantic. On January 13, 1942, U-123 struck first, sinking the British freighter Cyclops off Nova Scotia. Within days, U-boat commanders discovered an astonishing vulnerability: American coastal cities remained fully illuminated at night, silhouetting merchant ships against the glow and turning them into easy targets. The U.S. Navy, under Admiral Ernest King, had not yet organized coastal convoys, leaving individual freighters and tankers to sail alone along well-known shipping lanes from Maine to Florida and into the Gulf of Mexico. German crews, delighted by the abundance of undefended targets, called this period the 'American shooting season.'
Did You Know?
German U-boat crews were so astonished by the unblacked-out American coastline that some captains reported navigating by the glow of Miami's hotel lights and using the silhouettes of ships against the shore to pick their targets with ease.
Six Months of Slaughter
Between January and July 1942, U-boats devastated Allied shipping along the American seaboard, in the Gulf of Mexico, and throughout the Caribbean. Historians estimate that roughly 600 ships totaling more than 3.1 million tons were sunk during the Second Happy Time, with the heaviest losses concentrated off the U.S. East Coast in the campaign's first months. Tankers carrying vital oil from the Caribbean to refineries in the northeast were especially prized targets, and their burning wrecks were sometimes visible from beachfront resorts in Florida and New Jersey. Remarkably, German losses remained tiny by comparison: only a handful of U-boats were sunk in this period, since American forces lacked sufficient destroyers, aircraft, and coordinated tactics. Admiral King's reluctance to immediately adopt the convoy system, which the British had long championed, drew sharp criticism from Winston Churchill and contributed to the scale of the disaster, prolonging one of the most one-sided phases of the entire Battle of the Atlantic.
Convoys Close the Gap
By spring 1942, mounting losses forced American authorities to act. Coastal blackouts were finally imposed, merchant ships began sailing in escorted convoys, and the U.S. Navy expanded its fleet of subchasers, destroyers, and patrol aircraft, supplemented by British-loaned vessels and armed trawlers. A network of interlocking coastal convoy routes, from the 'Bucket Brigade' along the Eastern Sea Frontier to convoys through the Gulf and Caribbean, steadily closed the gaps U-boats had exploited. As Allied defenses tightened through June and July 1942, German losses rose sharply while sinkings declined. Recognizing that the easy hunting was over, Dönitz ordered his remaining U-boats to withdraw from North American waters on July 19, 1942, shifting operations back to the mid-Atlantic to target the main convoy routes between North America and Britain. The Second Happy Time was over, though the broader Battle of the Atlantic would rage for nearly three more years before Allied technology, code-breaking, and escort tactics ultimately defeated the U-boat threat in 1943.