German submarine U-1105

U-1105 was mounted with a single 3.7 cm Flakzwilling M43U gun on the LM 42U mount. The LM 42U mount was the most common mount used with the 3.7 cm Flak M42U. The 3.7 cm Flak M42U was the marine version of the 3.7 cm Flak used by the Kriegsmarine on Type VII and Type IX U-boats. U-1105 was mounted with two 2cm Flak C38 in a M 43U Zwilling mount with short folding shield on the upper Wintergarten.[3] The M 43U mount was used on a number of U-boats (U-190, U-250, U-278, U-337, U-475, U-853, U-1023, U-1058, U-1109, U-1165, and U-1306).

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  A single 3.7 cm Flak M42U gun on the LM 42U mount.
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  2 cm Flak C38 in a M 43U Zwilling mount with short folding shield.

U-1105 was one of only ten Type VIIC's to be fitted with a Balkongerät (literally 'Balcony apparatus or equipment'). The Balkongerät was used on U-boats (U-682, U-788, U-799, U-997, U-1021, U-1172, U-1306, U-1307 and U-1308).[3] The Balkongerät was standard on the Type XXI and the Type XXIII. Nonetheless, it was also fitted to several Type IXs and one Type X. The Balkongerät was an improved version of Gruppenhorchgerät (GHG) (group listening device). The GHG had 24 hydrophones, the Balkongerät had 48 hydrophones and improved electronics, which enabled more accurate readings to be taken.[4]

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  The outside view of the German design of Balcongerät installed on Type VIIC's

It was one of less than ten submarines that the Germans outfitted with experimental synthetic rubber skin of anechoic tiles 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 Alberich coating include: Type IIB – U-11; 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.[5][6][7]

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 torpedoes 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, HMS Redmill, 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 World War II.

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 and intercepted by the Sunderland "NS-V" of No. 201 Squadron RAF which then escorted it,[8] the submarine proceeded to the Allied base at Loch Eriboll, Scotland on 10 May 1945 to surrender.

Though still operated by her German crew, U-1105 was re-designated 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 Lisshally for several months before she was turned over to the United States as a war prize for study of its unique synthetic rubber skin.

In 1946, re-designated 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.

USS Salvager and USS Windlass were assigned to tow U-1105 into Chesapeake Bay where she was temporarily sunk. Salvage and towing tests were conducted from 10 to 25 August 1946. Moored on 29 September 1946 to allow pontoons to be fixed to her sides, U-1105 underwent another series of salvage and towing tests until 18 November 1946, when she was sunk off Point No Point Light, Maryland and buoys were left to mark the spot.

In the summer of 1949 U-1105 was raised again, towed into the Potomac River and anchored off Piney Point, Maryland, for preparations for her final demolition. On 19 September 1949, a 250-pound (110 kg) MK.6 depth charge was detonated 30 feet (9.1 m) from U-1105. After being lifted out of the water, she went down one last time in more than 91 feet (28 m) of water, landing upright on the river bottom, 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.