German submarine U-110 was a Type IXBU-boat of Nazi Germany's Kriegsmarine that operated during World War II. She was captured by the Royal Navy on 9 May 1941 and provided a number of secret cipher documents to the British. U-110s capture, later given the code name "Operation Primrose", was one of the biggest secrets of the war, remaining so for seven months. President Franklin D. Roosevelt was only told of the capture by Winston Churchill in January 1942.
Design
s were slightly larger than the original German Type IX submarines, later designated IXA. U-110 had a displacement of when at the surface and while submerged. The U-boat had a total length of, a pressure hull length of, a beam of, a height of, and a draught of. The submarine was powered by two MAN M 9 V 40/46 supercharged four-stroke, nine-cylinder diesel engines producing a total of for use while surfaced, two Siemens-Schuckert 2 GU 345/34 double-acting electric motors producing a total of for use while submerged. She had two shafts and two propellers. The boat was capable of operating at depths of up to. The submarine had a maximum surface speed of and a maximum submerged speed of. When submerged, the boat could operate for at ; when surfaced, she could travel at. U-110 was fitted with six torpedo tubes, 22 torpedoes, one SK C/32 naval gun, 180 rounds, and a SK C/30 as well as a C/30 anti-aircraft gun. The boat had a complement of forty-eight.
U-110 set out on her first patrol from Kiel on 9 March 1941. Her route to the Atlantic Ocean took her through the gap between the Faroe and Shetland Islands. Her first victim was Erdona which she damaged south of Iceland on 16 March. She also damaged Siremalm on the 23rd. This ship only escaped after she was hit by a torpedo which failed to detonate, and the U-boat's 105mm deck gun crew forgot to remove the tampion or plug in the muzzle before engaging their target. The resulting explosion on firing the first round wounded three men and compelled the boat to fire on the merchantman with the smaller 37 and 20 mm armament. Despite being hit, Siremalm successfully fled the scene, zig-zagging as she went. U-110 arrived in Lorient on the French Atlantic coast on 29 March, having cut the patrol short due to damage from the exploding gun.
2nd patrol and capture
The boat departed Lorient on 15 April 1941. On the 27th, she sank Henri Mory about west northwest of Blasket Islands, Ireland. Her next quarry were the ships of convoyOB 318 east of Cape Farewell. She successfully attacked and sank Esmond and Bengore Head, but the escort vessels responded. The British corvette,, located the U-boat with ASDIC. Aubrietia and British destroyer then proceeded to drop depth charges, forcing U-110 to surface.
Operation ''Primrose'' (9 May 1941)
U-110 survived the attack, but was seriously damaged. and Broadway remained in contact after Aubrietias last attack. Broadway shaped course to ram, but fired two depth charges beneath the U-boat instead, in an endeavour to make the crew abandon ship before scuttling her. Lemp announced "Last stop, everybody out", meaning "Abandon ship". As the crew turned out onto the U-boat's deck they came under fire from two attacking destroyers Bulldog and Broadway with casualties from gunfire and drowning. The British had believed that the German deck gun was to be used and ceased fire when they realised that the U-boat was being abandoned and the crew wanted to surrender. Lemp realised that U-110 was not sinking and attempted to swim back to it to destroy the secret material, and was never seen again. A German eyewitness testified that he was shot in the water by a British sailor, but his fate is not confirmed. Including Lemp, 15 men were killed in the action, and 32 were captured. Radio Officer Georg Högel and the rest of the crew were held at Camp 23, which is now the Monteith Correctional Complex. Bulldogs boarding party, led by sub-lieutenant David Balme, got onto U-110 and stripped it of everything portable, including her Kurzsignalecode book and Enigma machine. William Stewart Pollock, a former radio operator in the Royal Navy and on loan to Bulldog, was on the second boat to board U-110. He retrieved the Enigma machine and books as they looked out of place in the radio room. U-110 was taken in tow back toward Britain, but sank en route to Iceland. The documents captured from U-110 helped Bletchley Park codebreakers solve Reservehandverfahren, a reserve German hand cipher.
The 2000 film U-571 was partially inspired by the capture of U-110. In 2007, the submarine's chronometer was featured on the BBC programme Antiques Roadshow, from Alnwick Castle, in the possession of the grandson of the captain of the ship which captured her.
