U-110

U-110. It was a Type IXB submarine of the Kriegsmarine during the Second World War, notable for one of the most significant intelligence captures of the Battle of the Atlantic. Commissioned under Kapitänleutnant Fritz-Julius Lemp, the U-boat was involved in several patrols before its dramatic capture by Royal Navy forces from HMS Bulldog in May 1941. The seizure of its Enigma machine and associated code materials provided Bletchley Park cryptanalysts, including Alan Turing, with invaluable tools that profoundly influenced Allied naval intelligence and the broader Ultra program.

Background and construction

The vessel was ordered by the Kriegsmarine as part of the expansive German rearmament program preceding the outbreak of World War II. Constructed at the AG Weser shipyard in Bremen, a major hub for U-boat construction, its keel was laid down on 1 February 1940. As a Type IXB submarine, it was a larger, ocean-going design intended for extended patrols far into the Atlantic Ocean, boasting greater range and torpedo capacity than the more common Type VII submarine. The boat was launched on 25 August 1940 and formally commissioned into the Kriegsmarine on 21 November 1940 under the command of Fritz-Julius Lemp, who had previously commanded U-30 and was involved in the sinking of the SS Athenia at the war's start.

Service history

Following training with the 2nd U-boat Flotilla in Wilhelmshaven, U-110 was assigned to combat duty with the same unit. Its first patrol began in March 1941, departing from Kiel and operating in the North Atlantic. During this patrol, it engaged several Allied convoys, claiming damage to merchant shipping. The submarine's second and final patrol commenced in late April 1941, sailing from Lorient in Occupied France, a key U-boat base in the Battle of the Atlantic. Operating southwest of Iceland, it targeted Convoy OB 318, a vital stream of Allied merchant vessels. During these attacks, it successfully torpedoed and sank two ships, the SS Esmond and the SS Bengore Head, contributing to the tonnage war against British shipping.

Capture and intelligence value

On 9 May 1941, while attacking Convoy OB 318, U-110 was depth-charged and forced to the surface by the convoy's escorts, including the Royal Navy destroyer HMS Bulldog and the corvette HMS Aubretia. As the crew abandoned ship, believing the submarine to be sinking, a boarding party from HMS Bulldog led by Sub-Lieutenant David Balme seized the vessel. The capture was kept secret, and the U-boat was taken under tow. Aboard, the boarding party recovered an intact Enigma machine, its current rotors, and crucial code books, including the Kurzsignale short signal book and the officer-only Offizier settings. This material was swiftly transported to Bletchley Park, where analysts like Alan Turing and Gordon Welchman used it to break into the Kriegsmarine's Triton network, providing a continuous flow of decrypted German naval signals known as Ultra.

Aftermath and legacy

While under tow toward Iceland, U-110 foundered and sank on 10 May 1941, though the Admiralty maintained the fiction it had been destroyed to protect the secret of its capture. The crew, including Fritz-Julius Lemp, became prisoners of war; Lemp died in captivity in 1941. The intelligence coup remained classified for decades after the war. The captured materials directly aided the breaking of the U-boat Enigma cipher, allowing the Royal Navy to reroute convoys away from wolfpacks and contributing to the eventual Allied victory in the Battle of the Atlantic. The operation is often compared to the later capture of U-559 and its codebooks. The event has been featured in historical works and documentaries about naval warfare and signals intelligence.

See also

* German submarine U-505 * Operation Primrose * HMS Graph * Battle of the Atlantic (1939–1945) * Government Code and Cypher School

Category:Type IXB submarines Category:World War II submarines of Germany Category:Ships built in Bremen Category:1940 ships