On December 11, 1941, days after the Japanese attack on Pearl Harbor, Adolf Hitler addressed the Reichstag to declare war on the United States. Although American efforts to assist Great Britain were well underway, Hitler’s declaration officially brought the country into the European theatre. The United States was at war on both fronts.

By early 1942, the United States had drastically increased their naval presence in the Atlantic and presented a distinctive challenge to German U-boats who previously had patrolled with little resistance. This newfound challenge coerced U-boats to find less militarized areas to patrol and harass. The Nazis turned their attention the Gulf of Mexico. Heavy traffic from New Orleans and the consistent flow of oil from the region made the waters a prime target. The Gulf Coast was unprepared to defend against Nazi submarine attacks. The Nazis felt they could significantly undermine the American war effort if they could successfully disrupt the free flow of oil.

Dozens of advanced German U-boats cruised the vulnerable Gulf waters looking to down anything from passenger ships to oil tankers. At certain times the submarines would approach within miles of Louisiana’s coast. The Nazi submarine campaign of disruption and commerce raiding started flawlessly. Oil tankers, such as the Sheherezade, were struck with torpedoes. The Gulfpenn carried over 90,000 tons of oil at the time of its sinking. The Gulfamerica was carrying over 101,000 barrells of furnace oil went it was struck. The U-boats did not only target oil tankers. The Heredia, a United Fruit Company freighter, and the Oaxaca, a Mexican freighter, underwent similar fates. Traffic in the Gulf was in constant disarray as ships zigzagged their routes in a desperate attempt to avoid an attack. These attacks were deliberately underreported in the media for fear of causing widespread panic and to keep civilian morale high. Unbeknownst to many United States citizens, war was being raged right off their coast.

The United States provided escorts for many ships traveling throughout the Gulf but it seemed unproductive against advanced German submarines. On July 30, 1942, PC-566 was escorting Robert E. Lee, which contained survivors from a previous submarine attack, back to New Orleans. German submarine U-166 was patrolling the Mississippi River Delta just 25 miles from the Louisiana coastline. When Robert E. Lee approached the proximity, U-166 fired a torpedo into the side of the vessel. The ship took fifteen minutes to sink and killed twenty-five. PC-566’s captain, Herbert G. Claudius, retaliated. According to Claudius, he witnessed debris and oil float to the surface and saw no sign of the submarine. Although uncertain, he thought he had sunk the German submarine. However, the Navy felt his story was certainly untrue, especially since Claudius had not yet received anti-submarine training and sinking a German U-boat was a daunting task. Claudius was removed from command.

Toward the end of the conflict, German patrols rescinded and the U.S. increased their own patrols in the region. More importantly, the U.S. built the Big Inch and Little Inch petroleum pipelines from the south to the northeast, significantly decreasing oil traffic in the Gulf. In total, German U-boats sank over 70 vessels in the region, many alongside Louisiana’s coast. The campaign was known as “Operation Paukenschlag” (translated to “drumbeat”), and German submarine commanders nicknamed it “American shooting season.” Thousands died from these brutal attacks.

U-166 and Robert E. Lee were not discovered until May of 2001 during a pipeline survey. The ships were less than two miles from each other. There are no efforts to restore the German submarine as it was designated a “war grave” because of the 52 crew members entombed inside. It was not until the summer of 2014 when Oceanographer and National Geographic Explorer-in-Residence Dr. Robert Ballard credited the sinking to Claudius after mapping the submarine. He discovered the way in which the submarine was struck directly coincides with Claudius’ report. In December of 2014, the Navy studied Dr. Ballard’s findings and also credited Claudius with the sinking of U-boat 166. The Navy posthumously awarded him the Legion of Merit, a prestigious military award given for extraordinary achievements.

U-166 was the only submarine successfully sunk in the Gulf throughout the entire war. It demonstrated U-boats no longer enjoyed free reign in the region. With these new discoveries and findings, we can update an incredible saga in Louisiana history and finally pay tribute to the crew of PC-566 for their successful attack.

Sources and Further Reading:

“Operation Drumbeat: The Dramatic True Story of Germany’s First U-Boat Attacks Along the American Coast in World War II” by Michael Gannon.

“War in the Gulf,” C. J. Christ.