A total of 23 U-boats were stationed in the Gulf of Mexico during World War II. Over the course of the conflict, they took out a number of Allied vessels, with only one meeting a similar fate. U-166 had only been stationed in the area for a short while when she was taken out by an American ship – however, US Navy officials didn’t believe it at the time.
The Type IXC U-166 was commissioned into service with the Kriegsmarine in March 1942, in the midst of the Second World War. After undergoing training with the 4th U-boat Flotilla, she was transferred to frontline service with the 10th U-boat Flotilla. The vessel first patroled the British Isles, before traveling to France and, later, crossing the Atlantic for the Gulf of Mexico.
Over the course of the U-boat‘s short military career, she sunk four vessels: the Dominican sailing ship Carmen, the SS Oneida, Gertrude FV and the SS Robert E. Lee (1924). The latter encounter ultimately led to U-166‘s demise.
On July 30, 1942, U-166 torpedoed Robert E. Lee just south of the Mississippi River Delta, causing the ship to sink beneath the water’s surface. Her escort, the submarine chaser PC-566, launched a counterattack, with skipper Lt. Cmdr. Herbert G. Claudius claiming to have sunk the U-boat with depth charges. Navy officials didn’t believe this, however, and removed Claudius from his command. He was then sent to anti-submarine warfare school.
That same day, a US Coast Guard Grumman J4F-1 Widgeon spotted a U-boat off the coast of Louisiana. According to its crew, an engagement ensued and the aircraft hit the vessel. That same day, U-166 and her 52-man crew were reported as missing, despite no U-boat having been found following the attack.
The location of U-166‘s wreck remained unknown until 2001, when the remains of Robert E. Lee were found less than two miles from where the ship had been attacked. Sonar led researchers to the U-boat, some 6,650 feet below water. While the vessel was covered in silt, her conning tower and deck gun were still visible.
Given the remains of her crew remain within, U-166 was subsequently declared a war grave.
In 2014, a survey of the U-boat showed that her bow had been destroyed, with historians theorizing that a depth charge had hit the forward deck. When the munition exploded, it triggered the detonation of U-166 torpedoes, causing the vessel to sink.
As a result of this new information, it was determined that PC-566 had actually been responsible for the U-boat’s loss. Claudius was posthumously awarded the Legion of Merit with Combat “V,” with then-Secretary of the Navy Ray Mabus saying, “Seventy years later, we now know that [Claudius’s] report after the action was absolutely correct. [Claudius’s ship] did sink that U-boat, and it’s never too late to set the record straight.”
U-166 holds the distinction of being the only U-boat to have ever been lost in the Gulf of Mexico.