The wreck of U-550 was discovered off the coast of Massachusetts on 23 July 2012, in waters about 70 miles south of Nantucket.
A team of seven divers, lead by New Jersey attorney Joe Mazraani, located the wreck using sonar after a multi-year search. The team members were Joe Mazraani, Garry Kozak, Tom Packer, Steve Gatto, Eric Takakjian, Anthony Tedeschi and Brad Sheard. Mazraani said the next step is to contact any sailors or their families from the escort vessels, the tanker and the German U-boat to share the news and show the pictures. Another trip to the site is coming, he said, adding the investigation has just started. U-550 sailed from Kiel on 6 February 1944, heading for the North Atlantic, via the gap between Iceland and the Faroe Islands and conducted weather reporting duties before sailing for Newfoundland and subsequently the northeast coast of the United States. On 22 February the boat was unsuccessfully attacked south of Iceland by a Catalina flying boat of No. 162 Squadron RAF. However, two members of the U-boat's crew were killed. On 16 April, south of Nantucket Island, she located convoy CU 21, bound for Great Britain from New York City. The SS Pan-Pennsylvania, one of the largest tankers in the world, was unwisely straggling behind the convoy; U-550 torpedoed her. The ship quickly caught fire and began to sink. As the vessel settled, the submerged U-boat maneuvered underneath her hull in an effort to hide from the inevitable counterattack by the convoy's escorts. Convoy CU-21 was escorted by Escort Division 22, consisting of Coast Guard-manned destroyer escorts reinforced by one Navy DE, the Gandy (DE-764).
The escort division's flagship, Joyce (DE-317) and the Peterson (DE-152) rescued the tanker's surviving crew, while the Joyce detected the U-boat on sonar as the Germans attempted to escape after hiding beneath the sinking tanker. U-550's engineering officer later said, We waited for your ship to leave; soon we could hear nothing so we thought the escort vessels had gone; but as soon as we started to move bang! The Joyce delivered a depth-charge pattern that bracketed the submerged submarine. The depth charges were so well placed, a German reported, that one actually bounced off the U-boat's deck before it exploded. The attack severely damaged U-550 and forced her to the surface, where the German sailors manned and fired their deck guns.
The Joyce, Peterson and Gandy returned fire. Gandy rammed U-550 abaft the conning tower and the Peterson dropped two depth charges which exploded near the U-boat's hull. Realizing they were defeated, the U-boat's crew prepared scuttling charges and began abandoning their boat. Joyce rescued 13 of U-550's crew, one of whom later died from wounds received during the fire-fight. The remainder of the U-boatmen went down with their submarine. The Joyce delivered the prisoners of war and the Pan Pennsylvania survivors to the authorities in Great Britain.