In 1942, the German submarine U-166 was sunk in the Gulf of Mexico after a confrontation with an American submarine chaser, following its successful torpedoing of the SS Robert E. Lee.

For decades, the exact location of its wreckage remained a mystery, submerged and obscured by the vastness of the ocean.

It wasn’t until 2001, during a routine underwater survey for oil and gas exploration, that the long-lost U-boat was discovered.



The German U-boat fleet, a significant component of the Kriegsmarine (German Navy), was instrumental in Hitler’s strategy to strangle the Allies’ maritime supply routes. As these U-boats wreaked havoc on Allied shipping, they forced the Allies to devise extensive convoy systems, fortified by warships and air patrols, to protect merchant vessels.

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U-166 was a Type IXC U-boat, a class known for its larger size and extended range, allowing it to operate far from German bases. Commissioned in 1942, U-166 represented the peak of German U-boat technology at the time. Its hull was designed to withstand immense pressure, and it was equipped with powerful torpedoes, making it a formidable adversary.

While many recognize the North Atlantic as the primary battleground for the U-boat campaigns, fewer realize the extent of German submarine operations in the Gulf of Mexico. This region was strategically targeted by the Germans because of its significance to American oil production and transportation. Disrupting shipping in the Gulf meant not only sinking ships but also potentially curtailing the flow of oil, a critical resource for the Allied war machine.

The Sinking Of U-166

On its singular patrol mission in the Gulf of Mexico, U-166 engaged in a deadly cat-and-mouse game with Allied vessels. One of its most notable engagements was with the American passenger ship SS Robert E. Lee.

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On July 30, 1942, U-166 fired its torpedoes, sinking the ship and resulting in the tragic loss of many lives. However, retribution was swift. The submarine was soon located and attacked by the submarine chaser PC-566, although the credit originally went to a naval aircraft.

Finding U-166

For years, the precise location of U-166 remained one of the many unsolved mysteries of the Second World War. These missing chapters of history were not due to lack of interest but rather the sheer challenges of underwater exploration. Depths, currents, and sediment accumulation often rendered even the most sophisticated equipment of earlier decades ineffective.

U-166 was found less than 2 miles away from the Robert E. Lee.

The turn of the century witnessed significant advancements in marine technology, particularly in the fields of deep-sea exploration and underwater imaging. Companies involved in offshore drilling started employing advanced sonar systems to map the ocean floor for resource extraction. It was during one such mundane survey in 2001 that fate intervened.

While Taylor Energy Company was primarily focused on surveying potential sites for an oil and gas pipeline off Louisiana’s coast, their sonar equipment revealed an anomaly. The initial readings hinted at a large, elongated structure, not consistent with natural formations typically found on the seafloor.

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Recognizing the potential significance, the company soon sought expertise from the Minerals Management Service and the Naval Historical Center. The collaboration of marine archaeologists, naval historians, and technical experts initiated a more targeted exploration of the site.

Upon closer examination using remotely operated vehicles (ROVs) equipped with cameras, the mystery began to unfold. The images relayed back to the surface unmistakably depicted the wreckage of a submarine.

The vessel’s design, damage patterns, and nearby artifacts painted a clear picture: the resting place of U-166 had been found. But the submarine was not alone. The nearby remnants of the Robert E. Lee bore witness to the submarine’s final moments of combat and underscored the interconnected fates of both vessels. The site where U-166 now lies has been designated a war grave for the 52 men that died.