Of the 156 U-boats that surrendered to the allies at the end of the war, 116 were scuttled as part of Operation Deadlight. The operation was carried out by the Royal Navy and it was planned to tow the submarines to three areas about 100 miles (160 km) north-west of Ireland and sink them. The areas were codenamed XX, YY and ZZ. The intention was to use XX as the main area for scuttling while 36 boats would be towed to ZZ for use as targets for aerial attack. YY was to be a reserve position where, if the weather was good enough, submarines could be diverted from XX to be sunk by naval forces. In the case of those submarines not being used as targets, the plan was to sink them with explosive charges, with naval gunfire as a fall-back option if that failed.
When Operation Deadlight was activated, it was found that many of the U-boats were in an extremely poor condition as a result of being moored in exposed harbours while awaiting disposal. Combined with poor weather, this meant that 56 of the boats sank before reaching the designated scuttling areas, and those which did, were generally sunk by gunfire rather than explosive charges. The first sinking took place on 17 November 1945 and the last on 11 February 1946.
U-boats excluded from Operation Deadlight
Several U-boats escaped Operation Deadlight. Some were claimed as prizes by Britain, France, Norway and the Soviet Union. Four were in East Asia when Germany surrendered and were commandeered by Japan (U-181 was renamed I-501, U-195 – I-506, U-219 – I-505, U-862 – I-502, and a fifth boat, U-511, had been sold to Japan in 1943 and renamed RO-500). Two U-boats that survived Operation Deadlight are today museum ships. U-505 was earmarked for scuttling, but American Rear Admiral Daniel V. Gallery argued successfully that she did not fall under Operation Deadlight. United States Navy Task Group 22.3, under then-Captain Gallery, had captured U-505 in battle on 4 June 1944. Having been captured, not surrendered at the end of the war, she survived to become a war memorial at the Museum of Science and Industry in Chicago. U-995 was transferred to Norway by Britain in October 1948 and became the Norwegian Kaura. She was returned to Germany in 1965, to become a museum ship in 1971.
Deadlight U-boats discovery
In the late 1990s, an approach was made to the British Ministry of Defence for salvage rights to the Operation Deadlight U-boats, by a firm which planned to raise up to a hundred of them. Because the U-boats were constructed in the pre-atomic age, the wrecks contain metals which are not radioactively tainted, and which are therefore valuable for certain research purposes. No salvage award was made, due to objections from Russia and the U.S. and potentially from Great Britain.
Between 2001 and 2003, nautical archaeologist Innes McCartney discovered and surveyed fourteen of the U-boat wrecks; including the rare Type XXI U-boat U-2506, once under the command of Horst von Schroeter; the successful Type IXC U-boat, U-155 commanded by Adolf Piening and the U-778, which was the most promising salvage.
In 2007, Derry City Council announced plans to raise the U-778 to be the main exhibit of a new maritime museum. On 3 October 2007, an Irish diver, Michael Hanrahan, died whilst filming the wreck as part of the salvage project. In November 2009, a spokesman from the council's heritage museum service announced the salvage project had been cancelled for cost reasons.
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- "Operation Deadlight" a 1945 Flight article