U‑1023: The “Black Wolf” in Swansea and the Long Road to Operation Deadlight

U-1023 at Plymouth
May 1945

Between November 1945 and February 1946, the Royal Navy carried out Operation Deadlight, the codename for the final disposal of the German U‑boat fleet surrendered at the end of the Second World War. After VE‑Day, the Allies debated the fate of the surviving vessels. The eventual agreement allowed only thirty U‑boats to be retained—ten each for the United Kingdom, the United States, and the Soviet Union—for technical evaluation. The remainder, more than a hundred submarines, were to be scuttled in the Atlantic, ending the long and bitter U‑boat war. Among the boats selected for destruction was U‑1023, a submarine whose brief but eventful career made her one of the most widely recognised U‑boats to reach British shores.

Construction, Commissioning, and Wartime Service

U‑1023 was laid down in 1943 as part of the Type VIIC/41 programme, a refined and strengthened development of the earlier VIIC class. She was commissioned on 15 June 1944 under Oberleutnant Wolfgang Strenger, a young commander trained in the final generation of U‑boat officers. Her construction reflected the pressures of a collapsing Reich: welding was hurried, fittings were functional rather than elegant, and the emphasis was on rapid deployment. Yet she carried the latest innovations, including the Schnorchel, which allowed her to run her diesel engines while submerged and thus avoid Allied aircraft.

Despite the overwhelming Allied dominance of the seas by 1944–45, U‑1023 completed one operational patrol, during which she sank one ship and damaged another, totalling 7,345 GRT and 335 tons. Her crew painted four silhouettes on her torpedo‑tube doors, a traditional mark of claimed victories. Whether all were accurate remains uncertain, but wartime U‑boat culture prized reputation as much as results. As one British sailor later remarked, “a black wolf must maintain its legend.”

Surrender at Weymouth

On 10 May 1945, two days after VE‑Day, U‑1023 became the first U‑boat to signal her position to the Admiralty, offering herself up for surrender. She arrived at Weymouth, where her crew were taken into custody and the boat was inspected by British naval officers. Her specifications were typical of her class—500 tons, 220 feet long, 20 feet in the beam—but her engines were powerful: two 1,250 h.p. diesels and two 500 h.p. electric motors, giving her a surface range of 10,000 miles at ten knots. For a vessel built in the dying months of the war, she remained a formidable machine.

A Victory Tour Around Britain

Rather than being immediately mothballed, U‑1023 was selected for a public exhibition tour along the west coast of the United Kingdom, a symbolic demonstration of the defeat of the U‑boat menace. She visited Plymouth, Brixham, Falmouth, Bristol, Swansea, Liverpool, Holyhead, Manchester, Fleetwood, Belfast, Glasgow, Greenock, Rothesay, and Oban, attracting hundreds of thousands of visitors. For many civilians, this was the first and only time they would see the inside of a submarine. They marvelled at the cramped bunks, the maze of pipes, the torpedo rooms, and the oak‑panelled radio compartment that resembled a miniature science museum. British sailors guided the tours, explaining how they had mastered the German controls despite every dial and lever being labelled in a foreign language.

The Swansea Visit: June 1945

The South Wales Evening Post reported her arrival in Swansea under the headline “The ‘Black Wolf’ Comes to Swansea.” A reporter described an extraordinary journey from Cardiff to Swansea aboard the captured submarine itself, arriving at the King’s Dock oiling jetty shortly before eight in the morning. The boat lay low and silent in the grey light, waiting for the tide that would carry her into the North Dock basin.

Crowds gathered early, eager for the rare chance to see a German submarine intact and under British command. Her conning tower bore the bold number U1023, flanked by a wolf’s head—said to be the personal insignia of her wartime commander—and a pair of crossed axe and hammer, the meaning of which even naval officers could not fully explain.

Henry Lionel Marsham

Lieutenant‑Commander Henry Lionel Marsham: The British Officer Behind the Tour

The British commanding officer of U‑1023 during her exhibition tour was Lieutenant‑Commander Henry Lionel Marsham, a man whose quiet professionalism and personal history added an unexpected local dimension to the submarine’s Swansea visit. Marsham belonged to a long‑established English family with traditions of public service, and his father had once worked with the Kilvrough estate during the tenure of Admiral Lyons, giving the family a direct connection to the Gower. Although Marsham had left Swansea as a child, the U‑1023 tour brought him back to the town in a role few could have imagined: the British captain of a surrendered German submarine.

Marsham’s wartime career placed him among the generation of naval officers who rose rapidly due to the demands of global conflict. By 1945 he had achieved the rank of Lieutenant‑Commander, a position entrusted with significant responsibility. His assignment to U‑1023 demonstrates the Admiralty’s confidence in his technical competence, adaptability, and ability to engage with the public. Operating a German submarine required mastery of unfamiliar machinery, yet Marsham and his crew handled the vessel with ease, navigating her safely between ports and explaining her workings to thousands of visitors.

His presence in Swansea symbolised a curious post‑war moment: a British officer with childhood ties to the town returning at the helm of a vessel that had once hunted Allied ships. Visitors who toured U‑1023 encountered Marsham not as a distant naval figure, but as a courteous guide, answering questions and representing the Royal Navy in a moment of victory and transition.

Inside the “Black Wolf”

A New Boat with a Deadly Reputation

Built in 1944, U‑1023 was a comparatively new vessel. Her Schnorchel apparatus allowed her to remain submerged for almost six continuous weeks, a capability that astonished many visitors. On the doors of her torpedo tubes were painted silhouettes of four ships she was claimed to have destroyed—one allegedly a British destroyer. The Admiralty had no record of such losses, but the markings remained, a reminder of the wartime bravado of the U‑boat arm.

Upper Works and Armament

Her upper works revealed the hurried construction of Germany’s final wartime months: rough ironwork, coarse welding, and fittings lacking the finish of earlier U‑boats. Yet her armament remained formidable—an 88‑mm quick‑firing gun, double‑barrelled flak weapons, and powerful binoculars with eight‑times magnification and a light‑gathering capacity of sixty.

A “Science Museum” Below Deck

Below deck, the submarine resembled a compact science museum. The radio room, lined with oak and mounted on rubber to absorb vibration, contained a curious mesh‑like device linked to the conning tower—originally a German aircraft‑detection system, now repurposed by the British crew. The living quarters stretched in a long, narrow line broken by watertight doors, with bunks stacked tightly and every inch of space used. A veteran petty officer described life aboard with dry humour: “If you sit down to dinner and a man needs to pass, you stand up. And when he opens the door, the draught is strong enough to blow your meal onto the next fellow’s plate.”

Despite the cramped conditions, the Royal Navy crew found the vessel surprisingly comfortable. She could make 17.8 knots on the surface and eight knots submerged, and her internal communications, steering gear, and telegraphs drew particular interest from visiting seamen.

British Efficiency on German Machinery

Every control, lever, and dial aboard the submarine remained labelled in German, yet the British crew handled the vessel with ease during the voyage from Cardiff. They spoke English, the machinery spoke German, and yet the work proceeded smoothly—a quiet testament to naval adaptability.

Operation Deadlight and Final Destruction

After her public tour concluded, U‑1023 was transferred to the Operation Deadlight assembly area. Between November 1945 and February 1946, the Royal Navy scuttled more than a hundred surrendered U‑boats in the Atlantic, towing them out to deep water and sinking them by gunfire, explosive charges, or simple flooding. U‑1023, despite her fame, was not among the thirty boats retained for study. She was towed into the Atlantic and scuttled, ending her brief but eventful career beneath the cold winter seas.