German submarine U-110 (1940)

German submarine U-110 was a Type IXB U-boat of the German 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-110's 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.

Service history
U-110's keel was laid down 1 February 1940 by AG Weser, of Bremen, Germany as 'werk' 973. She was launched on 25 August 1940 and commissioned on 21 November with Kapitänleutnant Fritz-Julius Lemp in command.

The boat was part of the 2nd U-boat Flotilla from her commissioning date until her loss. Lemp commanded U-110 for her entire career. In an earlier boat (GS U-30 (1936)), he was responsible for the sinking of the passenger liner SS Athenia on the first day of the war. The circumstances were such that he was considered for court-martial. He continued, however, to be one of the most successful and rebellious commanders of his day.

1st patrol
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 the Erdona which she damaged south of Iceland on 16 March. She also damaged the Siremalm on the 23rd. This ship only escaped after she was hit by a torpedo which failed to detonate, (although it left a large dent) 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 the Henri Mory about 330 mi west northwest of Blaskets Islands, Ireland.

Her next quarry were the ships of convoy OB 318 east of Cape Farewell (Greenland). She successfully attacked and sank the Esmond and the Bengore Head, but the escort vessels responded. The British corvette, HMS Aubretia, located the U-boat with ASDIC (sonar). HMS Aubretia and British destroyer HMS Broadway then proceeded to drop depth charges.

Operation Primrose
U-110 survived the attack, but was seriously damaged. HMS Bulldog and HMS Broadway remained in contact after HMS Aubretia's last attack. HMS 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. She surfaced, to the crew's relief, and 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 HMS 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 assumed that the boat, with vents open, would sink, and ordered radio operator Heinz Wilde to leave the codebooks and Enigma machine and get out; he is reported to have said "the U-boat is sinking". Another radio operator recovered personal effects, but left the secret material.

Lemp realised that U-110 was not sinking and attempted to swim back to it to destroy the secret material, but 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, 32 were captured.

Bulldog's boarding party, led by sub-lieutenant David Balme, got onto U-110 and stripped it of everything portable, including her secret documents and Enigma machine. William Stewart Pollock, a former radio operator in the Royal Navy and on loan to HMS 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 Scapa Flow.

The documents captured from U-110 helped Bletchley Park codebreakers solve Reservehandverfahren, a reserve German hand cipher.

Modern-day connections
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.

Other captured U-boats

 * GS U-505
 * U-570, later HMS Graph
 * GS U-744
 * GS U-1024