The American oil tanker
SS Pan Pennsylvania, one of the largest tankers in the world at the time, was part of a convoy bound for Londonderry, Northern Ireland. On 16 April 1944, one day after leaving New York Harbor, she was spotted by Kapitanleutnant Klaus Hänert’s
U-550 due east of New Jersey, about 70 nautical miles southwest of Nantucket. It was the first (and last) patrol for both the
U-550 and her captain. Hänert fired a single torpedo which hit the port side of the tanker. Between the impact and the evacuation, 15 of her 50 crew and 10 of the 31 USN Armed Guard party aboard the
Pan Pennsylvania were killed.
Three escorting destroyers- the
USS Joyce,
USS Peterson, and
USS Gandy (two of which were manned by Coast Guard crews)- pounced immediately. Hänert rushed toward the tanker wreck and put his boat directly underneath the stricken tanker in a desperate attempt to hide from the Americans’ sonar, but to no avail as the
Joyce detected her and attacked with depth charges critically damaged the boat. Realizing there was no escape other than abandoning ship, Hänert ordered it to the surface. Per U-boat doctrine, however, Hänert ordered his crew to man the deck guns to hold off the Americans long enough for the boat to be scuttled and the Enigma cipher thrown overboard. A brief gun battle ensued before the
U-550 was rammed by the
Gandy and subjected to a brutal torrent of fire from both the
Gandy and
Joyce. The
Peterson soon rushed in and delivered the killing blows.
Unlike most U-boat engagements, the *U-550’*s final minutes were photographed in real time and a dramatic series of photos was taken as she surfaced, her crew spilled out, and then she finally sank for good. Most the U-boat’s crew made it off before it went under, but only 12 men (including Hänert) were picked up by the Americans, the others drowning or dying from exposure in the frigid water.
Hänert and the captain of the
USS Joyce became friends after the war and stayed in touch for the remainder of their lives. Hänert even visited him in the US. The wreck of the
U-550 was lost until a group of amateur divers and history enthusiasts discovered it in 2012.
