On the afternoon of August 1, 1942, two days after the sinking of the Robert E. Lee, White and Boggs were flying a routine patrol south of Isles Dernieres, Louisiana. White, the pilot, spotted a submarine lying on the surface and quickly pulled the twin-engine plane into a position to attack. Boggs quickly sent a radio signal reporting the sighting, then checked that all was ready to release their single, 325-pound (150kg) depth charge. As the Widgeon dived past 250 feet, White shouted "NOW!" and Boggs hit the toggle switch to release the bomb.

U-171 makes a fast crash-dive as White and Boggs' J4F (top) banks around for a depth-charge pass. Patrolling aircraft quickly became the U-boats' main enemy, both in the Gulf of Mexico and, later, throughout the North Atlantic.

The submarine had completely submerged by this time, but Boggs thought he could see its dark shape through the water. The depth charge look to strike the water about twenty feet to one side of the submarine. White pulled the plane up and began circling. The two men watched as a light oil slick spread across the water where their depth charge had detonated.

White and Boggs were interrogated at length after their return to base, and were admonished not to repeat anything they'd seen. After the war, they were informed that they had been officially credited with the sinking of U-166. And that's where the matter stood for more than fifty years.

Assigning a "kill" to the Coastguardsmen seemed obvious. U-166 was the only German submarine lost in the Gulf of Mexico during the war. U-166 had been correctly identified as the boat that sank the Robert E. Lee near the mouth of the Mississippi, and it would be an easy thing for U-166 to have traveled the relatively short distance to Isles Dernieres in the two days since that attack. It seemed obvious, on the face of it, that Boggs and White had indeed sunk U-166.

But the discovery and positive identification of U-166 in 2001, lying just a short distance from the wreck of her last victim, the Robert E. Lee, threw Boggs and White's account into question: if they hadn't attacked U-166, what boat had they bombed?

None of the standard accounts, compiled from the logs of returning U-boats, mentioned being attacked by aircraft at the time and place reported by the Coastguardsmen. The C&C Technologies archaeologists who first made the discovery, Rob Church and Dan Warren, began by looking at those boats known to have been in the Gulf of Mexico at the time. Quickly their attention focused on U-171, commanded by Kapitanleutnant Günther Pfeffer (1914-66).  U-171 had been operating in the same area as U-166, but was sunk when she struck a mine just a few hours out of her home port of Lorient, France. The boat sank almost immediately, taking with her 22 of the 52-man crew. Pfeffer survived, although his detailed log and notes from the patrol were lost. Pfeffer subsequently prepared a report roughly outlining the events of the patrol, but without a written record he was unable to assign specific dates to most of the events he described. In Pfeffer's reconstructed logs he mentioned that between July 27 and August 13, 1942 a "flying boat" had dropped one depth charge on them and they escaped with no damage. This description fits Boggs and White's account, and helps to confirm that it was U-171, not U-166, that the men's Widgeon had attacked.

Additional sources:

Melanie Wiggins, Torpedoes in the Gulf: Galveston and the U-Boats, 1942-1943 (College Station: Texas A&M University Press, 1995).

Articles online at Uboat.net.