During World War II, German U-boats came remarkably close to American shores, particularly in the early years of the conflict. The period between 1942 and 1943, known as the "Second Happy Time" for the German U-boat fleet, saw these submarines operating in waters off the eastern and southern coasts of the United States, with some even reaching as far as the Gulf of Mexico.
The U-boats' proximity to American shores was due in part to the success of the German naval strategy, which aimed to disrupt Allied shipping and weaken the U.S. economy. The campaign, known as the Battle of the Atlantic, escalated dramatically after the United States entered the war in December 1941. German U-boats, using wolf-pack tactics (multiple submarines coordinating attacks on Allied convoys), inflicted significant damage on merchant ships and even warships along the U.S. East Coast, particularly between New York and Florida.
U-boats frequently operated just offshore, making it difficult for American forces to detect and intercept them. German submarines were known to sink ships just miles from the American coastline, and they attacked vulnerable targets such as oil tankers, merchant ships, and even coastal freighters. By early 1942, U-boats had sunk dozens of vessels along the U.S. East Coast, often within sight of land. The coastal cities, especially along the eastern seaboard, lived in fear of attacks, and many residents witnessed the explosions and fires resulting from U-boat strikes.
The U-boats' proximity to American shores diminished after 1943, as the U.S. Navy developed more effective countermeasures, including improved radar, convoy systems, and the use of long-range aircraft for patrolling the coastline. By mid-1943, the Allies had largely gained control over the Atlantic, significantly reducing the threat posed by German U-boats near American shores. Nonetheless, the early U-boat attacks highlighted the vulnerability of the U.S. to submarine warfare and underscored the importance of naval defense during the war.