'Pledge' was the Allied naval programme under which U-boats surrendered at sea to Allied naval forces after the surrender of Germany (9/31 May 1945).

'Pledge' therefore filled the gap between the surrender of the U-boats in Europe during May 1945 and their final disposal either by sinking in 'Deadlight' or their allocation to the UK, USA and USSR. 'Pledge' thus encompassed the transfer of U-boats which surrendered, either at sea or in port, to the British anchorages in Lough Foyle in Northern Ireland and Loch Ryan in south-western Scotland.

To ensure total German naval disarmament, the British intended that at the end of hostilities all U-boats would immediately be removed to the UK and held there until they were destroyed. In the first half of 1944, therefore, the Royal Navy began detailed planning for the post-war transfer of all surviving U-boats to British ports.

In a message to the Admiralty on 5 August 1944, Admiral Sir Max Horton, commander-in-chief of the Western Approaches Command, suggested that the 238 U-boats then 'guesstimated' as the number likely to survive to the end of the war, should be moved to and stored at four UK naval anchorages. These were Lisahally in Northern Ireland (70 U-boats), Loch Ryan in south-western Scotland (100 U-boats), and two anchorages in the Gare Loch in western Scotland, where Roseneath could accommodate 36 U-boats and Faslane 32 U-boats. The total of 238 boats was an estimate based on current intelligence, and it was not foreseen at that time that in May 1945 their crews would scuttle more than half of the surviving total of operational U-boats.

On 21 September 1944 the Admiralty signified its basic agreement to Horton’s plan, but advised that any final decision would be delayed pending discussions about the number of Royal Navy personnel who would be required for the task, as well as wider issues relating to Allied agreement about the disposal of the surviving U-boats.

As the end of the war approached, the number of U-boats thought likely to surrender was much reduced, and thus the Royal Navy’s plan came to be centred on just Lisahally near Londonderry, in Lough Foyle and the anchorage at Cairnryan in Loch Ryan.

On 19 March 1945 Horton requested clarification from the Admiralty about the detailed procedures for the U-boats' surrender and subsequent internment at Lisahally and Loch Ryan. A meeting was held at the Admiralty on 27 March to discuss the outstanding questions as Horton wished to issue early executive instructions for dealing with the surrendering U-boats. The process was to be split into two stages: first was the surrender of U-boats at sea in 'Pledge I', and second was the disposal of U-boats in German and German-controlled ports in 'Pledge II'.

A number of important points were agreed by the Admiralty, these including that, for planning purposes, it should be estimated that no more than 160 U-boats might surrender in the British occupation zone, which included northern Germany, Denmark and Norway. It was also agreed that these surrendered U-boats would be transferred to be held in equal numbers at Lisahally and Loch Ryan, where only minimal maintenance would be provided because the UK was continuing to seek Allied agreement to the complete scrapping or sinking of the boats as soon as possible after the end of hostilities. It was also agreed that any U-boats surrendering in Norway and Denmark should be moved at the earliest possible opportunity in order to protect the crews from local reprisals.

It was confirmed that all boats which surrendered in the British zone would be sailed in groups to Lisahally or Loch Ryan, but only after being rendered incapable of operation. It was proposed that the crews of the boats moored in Loch Ryan should live afloat, but as those at Lisahally would be lying alongside the jetty, the German sailors would be accommodated in a nearby camp.

After the meeting of 27 March, detailed arrangements were made for the transfers. Loch Eriboll in the extreme north of mainland Scotland was designated as the port for preliminary examination, Loch Alsh as the port for final examination, and Lisahally and Loch Ryan as the ports for laying-up. Loch Eriboll had been selected as it was a remote anchorage where minimum damage could be done by any rogue boat, and Loch Alsh in western Scotland as it was sheltered, could accommodate 33 boats at buoys at any one time, and possessed a naval organisation and a railhead.

On 4 May the German navy had issued orders for all U-boats to cease operations and return to Norwegian ports, and after this the Kriegsmarine’s surrender proceeded in two phases. Firstly, there was the surrender of all German armed forces in the Netherlands, Denmark and north-western Germany (including the Frisian Islands, Heligoland and all the islands in Schleswig Holstein) to Field Marshal Sir Bernard Montgomery’s 21^st Army Group. This was signed on 4 May, came into effect at 08.00 on 5 May, required all German forces to lay down their arms and to surrender unconditionally, and specifically included all naval ships in these areas.

Then there was the general German surrender signed at Reims on 7 May which came into effect at 00.01 on 9 May. This led, on 8 May, to the issue of the specific pre-planned Admiralty order (under the codeword 'Adieu') that all U-boats, including those in Norwegian ports, were to surrender with effect from 00.01 on 9 May, and that those at sea were to head for designated reception ports, of which the most important was Loch Eriboll.

As a result of these instructions, 156 U-Boats surrendered to the Allies on both sides of the Atlantic.

In order to implement 'Pledge' it had been necessary to organise suitable reception arrangements in the naval anchorage at Loch Eriboll, which had no permanent Royal Navy port facilities. Thus, on 6 May the 21^st Escort Group was ordered to proceed to the Loch to secure the anchorage and prepare for the surrender of a then unknown number of U-Boats. The 21^st Escort Group and other naval units which comprised the Loch Eriboll Force arrived on 9 May.

The first U-boat to surrender arrived in Loch Eriboll on 10 May, and between then and 18 May, another 17 U-boats arrived in Loch Eriboll: on 10 May U-1009, U-1058, U-1105 and U-1305; on 11 May U-293, U-802, U-826 and U-1109; on 12 May U-956; on 13 May U-532, U-825 and U-1231; on 14 May U-244, U-516, U-764 and U-1010; on 17 May U-255; and on 18 May U-2326 which had previously surrendered in Dundee.

None of these boats spent long at Loch Eriboll, and with Royal Navy armed guards on board, were moved quickly to Loch Alsh, where the majority of the German crews were taken into captivity, and from there the boats were moved to Lisahally pending final disposition.

On 16 May the Norwegian destroyer Stord sighted a convoy of German naval vessels, including 15 U-boats (U-278, U-294, U-295, U-312, U-313, U-318, U-363, U-427, U-481, U-668, U-716, U-968, U-992, U-997 and U-1165), being moved to Trondheim from Narvik where they had surrendered on 9 and 10 May. This convoy was intercepted by the 9^th Escort Group on the following day and, instead of being allowed to continue to Trondheim, was directed to the UK as part of 'Pledge'. The 15 U-boats were then escorted across the North Sea to Loch Eriboll, which they entered on 19 May.

By midnight on 21 May, all of the boats had sailed for Loch Alsh for onward movement to Lisahally, where the last of the 33 U-boats which had either surrendered or been processed at Loch Eriboll arrived on 23 May.

Once the 15 U-boats from Norway had been processed it seemed probable that no more U-boats would surrender at Loch Eriboll, so the 'Pledge' reception organisation was moved on 28 May from Loch Eriboll to Scapa Flow in the Orkney islands group, where the World War I battleship Iron Duke as the base and depot ship, in order to process the remaining U-boats which had surrendered in Norwegian ports and thus needed to be moved to Lisahally or Loch Ryan. The process received greater impetus because, as a result of the German navy’s order of 4 May that all fully operational U-boats in German and Danish ports and waters should proceed to Norway, by mid-May the Norwegian ports were over-crowded with surrendered German naval vessels. The urgent need to clear Norwegian ports led the Admiralty to order on 24 May that all serviceable U-boats should be moved to the UK as soon as possible. This was supported by a 25 May instruction from the Allied naval headquarters that the sailing of these U-boats should be accorded the highest priority.

The first group of 12 surrendered U-boats from Norway, in he form of four from Oslo (U-170, U-874, U-975 and U-1108) and eight from Stavanger (U-637, U-901, U-1171, U-2322, U-2324, U-2329, U-2345 and U-2348) reached Scapa Flow on 30 May and, after processing, were sent to Lisahally and Loch Ryan. By 5 June another 52 U-boats reached Scapa Flow from Norway, and transferred without delay to Lisahally or Loch Ryan: these were, on 31 May, 24 boats (U-483, U-773, U-775, U-861, U-953, U-978, U-994, U-1019, U-1064 and U-1203 from Trondheim, U-245, U-298, U-328, U-868, U-928, U-930, U-1002, U-1004, U-1022, U-1052, U-1061, U-1272 and UD-5 from Bergen, and U-281 from Kristiansand); on 1 June 13 boats (U-299, U-369, U-712, U-1163, U-2321, U-2325, U-2335, U-2337, U-2350, U-2353, U-2354, U-2361 and U-2363 from Kristiansand); on 2 June one boat (U-3035 from Stavanger); on 4 June 13 boats (U-218, U-539, U-778, U-875, U-907, U-991, U-1004, U-1005, U-1057, U-1271, U-1301, U-1307 and U-2328 from Bergen); and on 5 June one boat (U-2334 from Kristiansand).

Like the boats which had been processed in Loch Eriboll, the 64 boats processed at Scapa Flow remained there for only a short time. In this instance, though, as Scapa Flow was a full Royal Naval base, they did not need to transit via Loch Alsh to disembark German prisoners, but instead were moved directly to Lisahally (14 boats) or Loch Ryan (50 boats). The last group of boats departed Scapa Flow on 6 June, and the 'Pledge' reception force at Scapa Flow was then disbanded.

After 5 June there were still 35 seaworthy surrendered boats in the ports of Norway (10 boats) and Germany (25 boats). In the latter case, they were all located at Wilhelmshaven, having been transferred there from the Danish and other German ports in which they had initially surrendered early in May. These boats were transferred directly to Lisahally or Loch Ryan between 3 June and 30 June.

The 10 boats from Norway were U-2502, U-2513, U-2518, U-3017, U-3041 and U-3515 from Horten on 3 June; U-2539 from Kristiansand on 3 June; U-3514 from Bergen on 6 June; and U-2506 and U-2511 from Bergen on 17 June.

The 25 boats from Germany, all from Wilhelmshaven, were U-883, U-2336, U-2341, U-2351, U-2356 and U-3008 on 21 June; U-155, U-806, U-1230 and U-1233 on 22 June; U-368, U-1102, U-1103, U-1110 and U-1194 on 23 June; U-291, U-680, U-720, U-779 and U-1198 on 24 June; and U-143, U-145, U-149, U-150 and U-739 on 30 June.

These boats were moved directly to Lisahally or Loch Ryan via the Pentland Firth sea route to the north of Scotland and, in many cases, were escorted by the British warships which had been part of the Scapa Flow reception force.

U-485 and U-541 had surrendered at Gibraltar and were transferred to Northern Ireland (the first to Loch Ryan and the second to Lisahally), and U-249, U-776 had surrendered at Portland in the south of England and were also transferred to Northern Ireland (the first straight to Loch Ryan, the second to Loch Ryan after a tour of British east coast ports, and the third to Lisahally after a tour of British west coast ports).

U-760, which had been interned in neutral Spain since September 1943 but was not part of the formal surrender process, was moved to Loch Ryan on 23 July.

There were also U-1406 and U-1407) which had surrendered in Cuxhaven on 5 May, been vacated by their crews, and were then scuttled by a German naval officer on 7 May, making them unavailable for transfer to the UK as part of 'Pledge'. The officer concerned was Oberleutnant Gerhard Grumpelt, who was tried by a British court in Hamburg, found guilty of disregarding the surrender agreement, and sentenced to five years in prison.

Finally, there were eight surrendered boats remaining in other European continental ports. All of these were unseaworthy, and comprised U-510 at St Nazaire in France, and U-310 at Trondheim, U-315 Trondheim, U-324 at Bergen, U-926 at Bergen, U-995 at Trondheim, U-1202 at Bergen and U-4706 at Kristiansand in Norway. These eight boats were not transferred to Northern Ireland, and were either scrapped or eventually taken into use by their 'host' nations.

A total of 156 U-Boats surrendered either from sea or in ports at the end of World War II in Europe. Of these, nine had surrendered from sea in Canada, the USA and Argentina, eight of those in European ports were unseaworthy, and two had been scuttled in Germany just two days after their surrender. Thus 137 surrendered boats were transferred to Lisahally or Loch Ryan to await decisions on their final dispositions, and of these 33 were moved via Loch Eriboll and Loch Alsh, 64 via Scapa Flow, and 35 directly from Norwegian and German ports via the sea route to the north of Scotland. The remaining five were transferred independently, as was U-760 which had been interned in Spain since 1943.

During the first part of this period, farther to the north the last two Arctic convoys, the outbound JW.67 and inbound RA.67, passaged from the Clyde river to the Kola inlet and back with 26 and 25 ships respectively. Their escort included Captain K. J. D’Arcy’s escort carrier Queen escorted by the destroyers Onslow and Obdurate, as well as Commander E. H. Chavasse’s British 4^th Escort Group (frigates Bentinck, Bazeley, Byard, Drury and Pasley) and Lieutenant Commander E. G. Old’s Canadian 9^th Escort Group (frigates Loch Alvie, Matane, Monnow, Nene and St Pierre).

The JW.67 convoy reached the Kola Inlet on 20 May and the RA.67 convoy departed on 23 May to reach the Clyde river on 30 May. On the outward passage the 9^th Escort Group was detached on 16 May to prevent the U-boats of the Arctic area from proceeding from the Vestfjord to Trondheim, and to accompany them to Loch Eriboll on 19 May. These boats included U-278, U-294, U-295, U-312, U-313, U-318, U-363, U-427, U-481, U-668, U-968, U-992, U-997, U-1165 and, as a late arrival, U-716.