German submarine U - 1105 German submarine " U - 1105 " , a modified Type VII - C / 41 German U - boat , was built at the Nordseewerke Shipyard , Emden , Germany , and commissioned into the Kriegsmarine on 3 June 1944 . Oberleutenant Hans - Joachim Schwarz was given command . He would command " U - 1105 " for the duration of her German service . Service history . Kriegsmarine . It was one of less than ten submarines that the Germans outfitted with experimental synthetic rubber skin of anechoic tile s designed to counter Allied sonar devices . Codenamed " Alberich , " after a sorcerer from ancient Norse mythology , this top - secret rubber coating process ultimately contributed to the ship ' s survival under extreme combat conditions and earned it the name " Black Panther . " For this reason , a black panther sprawled across the top of the globe was painted on " U - 1105 ' s " conning tower . U - boats with the " Alberich " coating include : Type IIB — ; Type VIIC — U - 480 , U - 485 and U - 486 ; Type VIIC / 41 — " U - 1105 " , U - 1106 , U - 1107 , U - 1304 , U - 1306 and U - 1308 ; Type XXIII — U - 4704 , U - 4708 and U - 4709 . After trials in the Baltic Sea and final outfitting in Wilhelmshaven , the submarine began patrolling Allied convoy routes near Blackrock , Ireland in the spring of 1945 . In April , " U - 1105 " escaped detection by an Allied destroyer patrol . Days later , the U - boat detected three British destroyers that were part of the Second Division of the 21st Escort Group . The submarine fired two acoustic torpedo es at a range of 2000 meters and then dove to 100 meters to escape a counterattack . Fifty seconds passed before the first torpedo struck , with the second hitting just moments later . Thirty - two crewmen from " U - 1105 ' s " victim , , were lost . The Allied search for " U - 1105 " and the search for " Redmill ' s " survivors began immediately . The submarine , unable to maintain its 330 - foot depth , sank to the bottom at 570 feet , remaining motionless . For the next 31 hours , the Allied squadron searched for the U - boat without success . " U - 1105 " evaded detection for the remainder of the Second World War . On 4 May 1945 , " U - 1105 " received the last order from Grossadmiral Karl Dönitz : the war is over . Ironically , the submarine surrendered to the 21st Escort Group , the same escort group it attacked just a few weeks earlier . Ordered to the surface , the submarine proceeded to the Allied base at Loch Eriboll , Scotland on 10 May 1945 to surrender . Royal Navy . Though still operated by her German crew , " U - 1105 " was redesignated as the Royal Navy submarine N - 16 and sailed under armed frigate and air escort along with other surrendered U - boats , through the North Minch to the British naval base at Lochalsh , then to Lisahally , Northern Ireland . Given a British caretaker crew she sat at Lishally for several months before she was turned over to the United States as a war prize for study of its unique synthetic rubber skin . United States Navy . In 1946 , redesignated U - 1105 , the U - boat arrived in Portsmouth , New Hampshire . The Naval Research Laboratory in Washington , D . C . , and Massachusetts Institute of Technology ' s Acoustic Laboratory in Cambridge , Massachusetts , conducted research on its unique rubber - tiled skin . After the research was completed , the boat was towed to Solomon ' s Island , Maryland for explosives testing . In the summer of 1949 " U - 1105 " was raised again and towed into the Potomac River and anchored off Piney Point , Maryland for preparations for her final demolition . On 19 September 1949 , a 250 lb . MK . 6 depth charge was detonated 30 feet from " U - 1105 " . After being lifted out of the water , she went down one last time in more than 91 feet of water landing upright , her pressure hull cracked open by the explosion all the way around to the keel . Little evidence was left to mark the wreck , so for the next 36 years the submarine was lost to history . The wreck . On 29 June 1985 , the wreck of " U - 1105 " was discovered by a team of sport divers led by Uwe Lovas , approximately one mile west of Piney Point , Maryland , at . In November 1994 , it was designated as Maryland ' s first historic shipwreck preserve . The program , the first of its kind in the state , was designed to promote the preservation of historic shipwreck sites while making them accessible to the general public . At the wreck site , the conning tower rises to within 68 feet of the surface . The wood covered main deck fore and aft of the conning tower is occasionally exposed by the drifting silt beds . The wreck is well preserved , and largely intact . Seasonally , thick layers of marine growth appear and then disappear on the site , often covering structural features . Between April and December , a large blue and white mooring buoy is anchored about 70 feet from the wreck , while a small , orange ball float is anchored to the stump of the forward ( air - search ) periscope . The site is maintained for the Maryland Historical Trust by the Institute of Maritime History , and was placed on the National Register of Historic Places in 2001 .