Captured U-boats

by Gudmundur Helgason

U-110 - "The Secret Capture"

May 9, 1941. This is what most people view as the most important capture of the entire war and it was so secret that even the crew of U-110 did not know of it! U-110 (on its second patrol under the command of Kptlt Fritz Julius Lemp) had been attacking a convoy along with U-201 (Oblt Adalbert Schnee) when Lemp left his periscope up too long (probably to confirm a kill, he sank two ships on that day amounting to 7500 GRT) and the escort HMS Aubretia noticed it and rushed to the scene dropping depth charges.

U-110 survived the first attacks but then HMS Bulldog and HMS Broadway came and join in the hunt. U-110 was forced to surface and HMS Bulldog immediately went onto ramming course (its commander realized at the very last moment that a capture might come off and tried to evade hitting U-110 which he almost did) which Lemp noticed and ordered "Abandon Ship". Lemp figured that since the boat was going to be rammed (and presumably sunk) its secrets were safe within it. Only when he was in the water did he realize that the boat was not sinking and attempted to swim back and prevent capture and that was the last seen of him. Many say he was shot in the water by a British sailor but that may not be at all true.

The British made several journeys between U-110 and HMS Bulldog to collect whatever they could get their hands on inside the boat. This must have been a real treat as U-110 was abandoned in a hurry and being a IXB class she did not sink as rapidly as VIIC would likely have done. It is very likely that numerous U-boats were sunk using the material found inside U-110.

The day after the boat was captured someone realized that the allies already had the most important part of U-110, namely the secret documents and Enigma machine and that the Germans might find out that the British had the boat soon and, assuming the worst, change all codes and cipher system. The boat "accidentally" sank when being towed to Britain. 15 men were killed in the action and 32 captured. Lemp himself did not survive as noted above.


The boat left Trondheim, Norway under the command of Kptlt Hans Rahmlow on August 23rd, 1941 to operate in the North Atlantic on her first operational patrol before going to her La Pallice (France) base.

She was captured when Rahmlow raised his periscope at 1100hrs on August 27th and saw nothing and thus surfaced his almost stationary boat. Directly above (in its periscope 'blind spot') U-570 was Sqn Ldr J. H. Thompson in his Hudson 'S' on anti-submarine patrol from Iceland. He noticed the dream target and placed several well placed depth charges all around U-570 severely damaging her.

Shortly after his initial attack he saw a white flag being waved from the tower indicating the surrender. He contacted his superiors and was told to fly watch while they figured out how they could get vessels to the area. He was relieved by a Catalina flying boat in the evening and finally after 12 hours the trawler Northern Chief showed up but the weather was too bad to capture her at that time so she waited for reinforcements that arrived during the night in the form of the trawlers Kingston Agate, Windermere and Wastwater and the destroyer HMS Burwell. The last ship to the scene was the Canadian HMCS Niagara.

When she was finally captured by life rafts in the heavy seas there had been ample time to destroy all secret documents and internal fittings.

U-570 was towed to Iceland and beached there while being hastingly repaired before she was towed to Britain where she was to be commissioned into the Royal Navy as HMS Graph (pictured below) on Sept 29, 1941.

Former U-570, seen here as the British Submarine HMS Graph

As HMS Graph she even later fired a torpedo towards U-333 but missed. She later ran aground on the Island of Islay of Scotland. She was broken up in 1961.


Captured by the US Navy Hunter-Killer group 22.3 which included the aircraft carrier USS Guadalcanal and the destroyers USS Pillsbury, Pope, Flaherty, Jenks and Chatelain. The capture took place on Sunday June 4, 1944. 1 German was killed in the incident.

More information on this boat can be found on the U-boats Today page.


She was boarded by crew members from HMCS Chilliwack on March 6, 1944. They were only able to hoist the white ensign and collect some documents before she sank. At that time most of the information they could have gotten from those documents was likely already known by the allies. 12 Germans died.


She was captured by HMS Loch Glendhu on April 12, 1945 in the Irish Sea (south of Isle of Man) and taken in tow. She sank a few hours later when being towed by HMS Loch More. 9 Germans died in this incident.

German Captures

The Germans captured one enemy submarine during World War Two (at sea), the British HMS Seal Commanded by Lt. Cmdr. R. P. Lonsdale on May 5 1940. The boat was to mine the Kattegat but was hit by a mine (after laying her mines) causing her to land on the sea floor late on May 4. The crew managed to surface the badly damaged boat during the night and attempted to reach Swedish waters but were intercepted by two German Arado seaplanes and the boat was surrendered to the Germans. The boat was towed to Frederikshavn, Denmark by UJ 128.

HMS Seal was commissioned into the Kriegsmarine as UB but had limited value except for propaganda use. She was scuttled on May 3, 1945 in Heikendorf Bay (in position 54.22N, 10.11E). Her wreck was later raised and broken up.

This article was published on 4 May 1997.

Lone Wolf

Mulligan, Timothy P.

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Books dealing with this subject include

Donitz's Last Gamble. Lawrence Patterson, 2008.
False Flags. Stephen Robinson, 2016.
The Führer Led But We Overtook Him. Durham, Phil, 1996.
The Gironde Incident. Hughes, Michael, 1983. (transl.)
Graveyards of the Pacific. Ballard, Robert D., 2001.
His Majesty's U-boat. Reeman, Douglas, 1973.
Hitler and His Admirals. Martienssen, Anthony K., 1949. (transl.)
How I Captured a U-boat, and More. Johns, C. H., 1998.
Lone Wolf. Mulligan, Timothy P., 1993. (transl.)
On Fortune's Side. Anthony Molloy, 2012.
Opération Kiebitz. Dugas, Jean-Guy, 1992.
Operation Storm. John Geoghegan, 2013.
Podwodna wachta. Jegorow, Gieorgij, 1988.
Submarines. Preston, Antony, 1982.
A tale of two subs. Jonathan J. McCullough, 2009.
The War Below. James Scott, 2013.
Torpyedy VMF SSSR. Korshunov, Yu.L., and Strokov, A.A., 1994.
U-Boat Killer. Macintyre, Donald, 2000. (transl.)
Ubåt saknas. Warren, C.E.T and Benson, James, 1962.
We Captured a U-Boat. Gallery, Daniel V., 1957.
Will Not We Fear. Warren, C.E.T. and Benson, James, 1961.

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