British naval armed guards look on as a German submarine rating carries torpedo parts from the surrendered U-826 at Loch Eriboll,

Operation Deadlight – The End of the U-Boats

The Royal Navy’s executive action, Operation Deadlight, led to the sinking of 116 German U-Boats off Northern Ireland between 27 November 1945 and 12 February 1946. It was the culmination of the long-held determination of the British Government to ensure the total elimination of the Kriegsmarine’s submarine fleet after the end of hostilities.

Operation Deadlight
U-236 coming alongside U-826, for inspection by British officers at Loch Eriboll. Before surrendering U-826 had been on operational duties for five weeks © IWM A 28528

On 4 May 1945, shortly before he committed suicide, Hitler named Großadmiral Karl Dönitz as his successor as Head of State. One of Donitz’s first orders was to all combat U-boats to cease offensive operations and return to their bases. In a brief one-line message, it read: ‘All U-boats cease fire at once. Stop all hostile action against Allied shipping.’ 

Unknown to the Allies, in the last few days before the wars’ end, orders had gone out from Kriegsmarine headquarters under the code word Regenbogen for crews to commence scuttling their U-boats. By 8 May this action had accounted for 195 boats sunk.

Free Polish Navy destroyer ORP Krakowiak towing German Type XXIII U-boat U-2337 out to sea for scuttling from Lock Ryan on 28 November 1945 © Press Agency/Imperial War Museum

Many U-boats considered unseaworthy remained in French, German, Norwegian and Spanish ports, plus others that surrendered in Canada and the USA, but this still left 156 to be sailed into British home waters and handed over under the surrender terms.

Under the Tripartite Naval Commission agreement of 1945, 30 submarines of the most recent types were to be divided equally between the UK, USA and USSR. After the Allies had made their selections this left a balance of 116 to be disposed of by sinking under the Commission’s terms. These boats were transferred pending disposal to Lishally in Northern Ireland and to Loch Ryan in NW Scotland.

An aerial photograph of 42 surrendered U-boats moored at Lishally, Northern Ireland in June 1945, awaiting disposal by sinking under the terms of Operation Deadlight          

Operation Deadlight was the Royal Navy code name for the remaining 116 U-boats to be sunk at sea between 17 November 1945 and 11 February 1946. On 31 October 1945 the Admiralty instructed Commander-in-Chief Rosyth, Vice Admiral Sir William Jock Whitworth, to commence arrangements to dispose of 30 boats at Lishally and 86 boats at Loch Ryan in deep water off the north coast of Ireland starting from 25 November.

The U-boats comprised one Type IID, 76 Type VIIC, one Type VIID, one Type VIIF, 11 Type IXC, four Type IXD2, four Type XXI and 18 Type XXIII. The Royal Navy towed the unmanned boats out to sea but bad weather caused 20 of the U-boats to founder on tow; the demolition charges failed except on two occasions; only 13 air-attack sinking’s were effected instead of the planned 29; the torpedo exercise attacks were reduced from 13 to eight, leaving the balance of 73 submarines to be despatched by gunfire.

U2329 sails into Loch Ryan, June 1945. Commanded by Oblt. Heinrich Schlott, U2329 had surrendered in Stavanger, Norway, a month earlier.

In all, only 58 of the 116 U-boats reached the disposal area, the rest lie scattered in a line across the north coast of Donegal ranging in depth from 46m to 130m.

Operation Deadlight – Precious Metals

Because all 116 U-boats lying beneath the waves were constructed prior to when the two nuclear bombs were dropped on Japan in August 1945 and subsequent nuclear weapons testing during the Cold War, the wrecks contain metals that are not radioactively tainted, as are all metals produced since.

Pre-August 1945 metals are called Low-background steel, because modern steel is contaminated with a weak radioactive signal. Consequently Low-background steel is extremely valuable and needed to produce devices such as Geiger counters; sensitive medical instruments; scientific equipment; aeronautical sensors and for space exploration.


Operation Deadlight.U-155 ties up below Tower Bridge.
U-155 Deutschland ties up below Tower Bridge on 3rd December 1918. After the First World War U-155 became an exhibition boat before being broken up at Birkenhead in 1921

Most of the sunken submarines lie in previously marked coordinates and because of objections from Russia and the United States, the Ministry of Defence were denied awarding any salvage rights. The boats rest on the waterbed at depths of approximately 90m’s and salvage of over 50 boats was considered feasible by the late 1990’s. From 2001, nautical archaeologist Dr Innes McCartney, nicknamed the ‘U-Boat Hunter’, spent three years discovering, surveying and filming many of the wrecks, including the rare Type XXI U-boats U-2506 and U-2511. 

Silent footage from 1945 showing HMS Hesperus (H57) escorting surrendered German U-boats at Lisahally during Operation Deadlight.

For a more detailed account of Operation Deadlight see Derek Waller’s excellent article on U-Boat.net


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