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HMS Bulldog and the Enigma Machine

Lieutenant Commander David Balme, who has died aged 95, led a boarding party which captured the secrets of Enigma from a German U-boat during the Battle of Convoy OB138 in May 1941, a turning point in the Battle of the Atlantic.

At midday on May 9 1941 Commander Joe Baker-Cresswell, captain of the destroyer Bulldog, was about to order the ships of the 3rd Escort Group to leave west-bound trans-Atlantic Convoy OB318 in order to refuel at Iceland, when two merchant ships were torpedoed in quick succession. The torpedoes were fired from U-110, commanded by the U-boat ace Fritz-Julius Lemp, who failed to notice the proximity of the corvette Aubretia. Before his second salvo of torpedoes struck, Aubretia’s Lieutenant Commander Vivian Smith commenced a counter-attack with depth charges which blew U-110 to the surface.

Balme was ordered to row across in Bulldog’s whaler to “get whatever you can out of her – documents, books, charts, and get the wireless settings, anything like that”. Jumping on to the U-boat’s outer hull he walked, revolver in hand, to the conning tower, at which point he had to holster his pistol in order to climb three ladders to the top of the tower and down again inside the U-boat to the control room. It was, he later recalled, “a very nasty moment because both my hands were occupied and I was a sitting target to anyone down below”.

Balme was very frightened; he expected the boat to sink, or scuttling charges to blow up at any moment, or to be overcome by chlorine from damaged batteries. The inside of the boat was dimly lit, there was a “nasty” hissing noise, and he could hear water slopping in the bilges. “I immediately went right for’d and right aft with my revolver in my hand to see if there was anybody about,” he said later. Noting that despite damage the U-boat was clean and well-kept and there was food on the table, but finding no Germans aboard, Balme called down the boarding party and “started ransacking all the treasures of the U-boat”.

In the wireless office, telegraphist Alan Long found “a funny sort of instrument, Sir, it looks like a typewriter but when you press the keys something else comes up on it”. Balme recognised this as “some sort of coding machine”, which he ordered to be unscrewed, and he organised a human chain to carry the machine and other equipment, charts and documents up the ladders and into the whaler. Balme and Long had found an Enigma machine, the cipher device which the German U-boat service used to communicate to its fleet in, as the Germans thought, an unbreakable code.

Besides that day’s settings they also recovered the daily settings until the end of June, which, when delivered later to Bletchley Park, enabled Alan Turing and his team to read the German naval “Hydra” code, the officer-only code, and, with the knowledge and experience gained, to go on to crack several other codes. Lemp’s crew were so demoralised and ill-disciplined that later in prison camp they talked freely to their interrogators about U-110 and about other boats in which they had served. Balme and his men spent six hours inside U-110, where for some time they were left alone in the Atlantic, listening to the distant sound of depth charges while the 3rd Escort Group hunted another U-boat. When Bulldog returned, Balme passed a towline, and for a day U-110 was pulled towards Iceland, until about 11.00 on May 10 1941 when the German vessel reared its bows in the air and sank stern-first.

The loss of U-110 enabled the British to throw a cloak of secrecy over the whole affair, a cloak so dark that even when Captain Stephen Roskill, the official historian of the Royal Navy, wrote about the capture in 1959, only those already in the know were able to read between the lines and would have realised that the secret of the capture was not the U-boat but the Enigma material which was salvaged from it. Balme had been told that the truth of his secret capture would be kept forever, and was surprised when in the 1970s its secrets began to leak out. Baker-Cresswell and Smith were awarded the DSO, Balme the DSC, and Long the DSM, for enterprise and skill in action against enemy submarines.

There were also breaches of security: Baker-Cresswell had told Balme to bring him back a pair of binoculars. Balme brought back two, and he used these swastika-stamped Zeiss binoculars in his yacht for 50 years. He also pinched Lemp’s cap from his cabin, keeping it as a souvenir until he presented it to the Imperial War Museum in 2003.

David Edward Balme was born in Kensington, London, on October 1 1920, of Huguenot stock. Aged 13, David entered Dartmouth Naval College in the Anson term of 1934. Balme’s naval career was unusually varied. Pre-war, as a midshipman, he served in the cruisers London and Shropshire in the Mediterranean during the Spanish Civil War; he recorded the rising tension in Europe in his midshipman’s journal.

When he was re-appointed to the destroyer Ivanhoe in June 1939 she was on the Palestine Patrol, preventing illegal immigration into the Holy Land, and when she was recalled to Britain at the outbreak of war he witnessed the torpedoing of the carrier Courageous in September. In mid-October he took part in the Battle of Convoy KJF3 when two U-boats were sunk.

Balme had a very enjoyable few months on his foreshortened sub-lieutenant’s courses in Portsmouth and Greenwich in early 1940 and his next appointment was as sub-lieutenant of the gunroom in the cruiser Berwick. On November 27 1940 she fought against the Italian fleet in the Battle of Cape Spartivento, when she was hit by two 8in shells which knocked out her after turrets, killing seven men, wounding nine others and igniting a fire which took an hour to subdue. Then on Christmas Day that year Berwick was off the Canaries escorting Convoy WS-5A when, despite being hit several times, she drove off the German heavy cruiser Admiral Hipper, thus saving a valuable troop convoy bound round the Cape for the Middle East.

When Berwick returned to Plymouth for repairs, Balme was appointed to Bulldog as her navigator. Bulldog, he declared, was “a happy little ship and far the best time that I ever had in the Navy". While in her he took part in several trans-Atlantic convoys, and in the occupation of Iceland. Balme’s navigational skill led to him being selected as an observer in the Fleet Air Arm. En route to Egypt in June 1942 he commanded a party of British gunners on-board the American merchantman Chant, part of a convoy intended for the relief of Malta – but was sunk. Rescued from the water, he spent two nights in an air raid shelter in Malta before flying on to take up his duty as senior observer of 826 Naval Air Squadron. Balme’s Fairey Albacore bombers perfected the technique of pathfinding – dropping flares for RAF Wellingtons to bomb. When he left, in February 1943, the Air Officer Commanding sent him a signal of thanks for the “magnificent work with and for the Wellingtons.

There is no doubt that these night attacks were one of the decisive factors in crushing the enemy’s attack. The successful conclusion of the land battle may well prove to be a turning point in the war in Africa.” Balme was mentioned in dispatches. Next Balme qualified as fighter direction officer (FDO) and was sent to the battleship Renown, and when she brought Winston Churchill and his staff back from the Quebec Conference in September 1943 Balme studied him closely. Balme also attended the 21st birthday party of Mary Churchill (later Lady Soames). Almost Balme’s last appointment was as staff FDO in the Eastern Fleet, in the battleship Queen Elizabeth, when with acting rank he became the youngest lieutenant commander in the fleet. His service included a month in the escort carrier Empress directing her aircraft on photo-reconnaissance missions over Malaya.

Post-war Balme joined the family’s wool-broking business. He hunted with the New Forest Hounds and, as a member of the Royal Yacht Squadron, sailed the coasts of Western Europe. In 1999 Balme was historical adviser during the making of the Oscar-winning film U-571, which recast the capture and boarding of U-110 as an American victory. When the prime minister at the time, Tony Blair, called this an affront to British sailors, Balme, the one-time chairman of Lymington Conservatives, pointed out that it was a great film, that it would not have been financially viable without being Americanised, that the credits acknowledged the Royal Navy’s role in capturing Enigma machines and code documents, and that he was glad the story had been told in tribute to all the men involved. Balme married Susan in Thurn in 1947. She survives him with their two sons and a daughter. Lieutenant Commander David Balme, born October 1 1920, died January 3 2016
By email from Ian Shepherd

HMS Bulldog H91

HMS Bulldog, 1945
HMS Bulldog

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HMS Bulldog (H91) was a B-class destroyer built for the Royal Navy (RN) from 1929 to 1931. Initially assigned to the Mediterranean Fleet, she was transferred to the Home Fleet in 1936. During the Spanish Civil War of 1936–1939, the ship spent considerable time in Spanish waters, enforcing the arms blockade imposed by Britain and France on both sides of the conflict. Bulldog saw service throughout World War II on convoy escort duty during the Battle of the Atlantic and in the Arctic.

Her most notable actions were the capture of a complete Enigma machine and codebooks from the German submarine U-110 in 1941, and sinking another German submarine in 1944.

The surrender of the German garrisons of the Channel Islands was signed on 9 May 1945 aboard Bulldog. Redundant after the war, she was broken up for scrap in 1946.

Bulldog displaced 1,360 long tons (1,380 t) at standard load and 1,790 long tons (1,820 t) at deep load. The ship had an overall length of 323 feet (98.5 m), a beam of 32 feet 3 inches (9.8 m) and a draught of 12 feet 3 inches (3.7 m).She was powered by Parsons geared steam turbines, driving two shafts, which developed a total of 34,000 shaft horsepower (25,000 kW) and gave a maximum speed of 35 knots (65 km/h; 40 mph). Steam for the turbines was provided by three Admiralty 3-drum boilers. Bulldog carried a maximum of 390 long tons (400 t) of fuel oil that gave her a range of 4,800 nautical miles (8,900 km; 5,500 mi) at 15 knots (28 km/h; 17 mph).

The ship's complement was 134 officers and enlisted men, which increased to 142 during wartime.

Bulldog mounted four 45-calibre quick-firing (QF) 4.7-inch Mk IX guns in single mounts, designated 'A', 'B', 'X', and 'Y' from front to rear. She was briefly fitted with a C XIII mount capable of 60-degree elevation for testing purposes. For anti-aircraft (AA) defence, Bulldog had two 40-millimetre (1.6 in) QF 2-pounder Mk II AA guns mounted on a platform between her funnels. She was fitted with two above-water quadruple torpedo tube mounts for 21-inch (533 mm) torpedoes. One depth charge rail and two throwers were fitted; 20 depth charges were originally carried, but this increased to 35 shortly after the war began. The ship was fitted with a Type 119 ASDIC set to detect submarines through sound waves beamed into the water that would reflect off the submarine.

By April 1941, the ship's AA armament had been increased when the rear set of torpedo tubes was replaced by a 3-inch (76.2 mm) (12-pounder) AA gun. In late 1941, the ship was converted to an escort destroyer with the replacement of her 'A' gun by a Hedgehog anti-submarine spigot mortar. By April 1943, the 'Y' gun had been removed to compensate for the increase to 70 depth charges. Additional depth charge stowage later replaced the 12-pounder high-angle gun. The 2-pounder mounts were replaced by 20-millimetre (0.8 in) Oerlikon autocannon and two additional Oerlikon guns were also added in the forward superstructure.

To combat German E-boats, a QF 6-pounder gun was mounted at the very tip of the bow in 1944.

German submarine U-110

German submarine U-110 was a Type IXB U-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-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.

U-110's keel was laid down 1 February 1940 by DeSchiMAG AG Weser, of Bremen, Germany as yard number 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 (U-30), 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.

The U-110 had a successful career prior to her capture, having attacked five convoy ships, sinking three and damaging the other two.
The boat departed Lorient on 15 April 1941. On the 27th she sank Henri Mory about 330 nautical miles (610km; 380mi) west northwest of Blasket Islands, Ireland.

Her quarry on her second patrol was the ships of convoy OB 318 east of Cape Farewell (Greenland). She successfully attacked and sank the Esmond and Bengore Head, but the escort vessels responded. The British corvette, HMS Aubretia, located the U-boat with ASDIC (sonar). HMS Aubretia and British destroyer Broadway then proceeded to drop depth charges, forcing U-110 to surface.

Operation Primrose.

U-110 survived this initial attack, but was seriously damaged. HMS Bulldog and Broadway remained in contact after Aubretia's 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, 32 were captured.

Enigma Machine

Enigma Machine
Military Enigma machine (in wooden box)

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The Enigma machines were a series of electro-mechanical rotor cipher machines developed and used in the early- to mid-twentieth century to protect commercial, diplomatic and military communication. Enigma was invented by the German engineer Arthur Scherbius at the end of World War I. Early models were used commercially from the early 1920's, and adopted by military and government services of several countries, most notably Nazi Germany before and during World War II. Several different Enigma models were produced, but the German military models are the most commonly recognised. However, Japanese and Italian models have been used.

German military messages enciphered on the Enigma machine were first broken by the Polish Cipher Bureau, beginning in December 1932. This success was a result of efforts by three Polish cryptologists, Marian Rejewski, Jerzy Różycki and Henryk Zygalski, working for Polish military intelligence. Rejewski reverse-engineered the device, using theoretical mathematics and material supplied by French military intelligence. Subsequently the three mathematicians designed mechanical devices for breaking Enigma ciphers, including the cryptologic bomb. From 1938 onwards, additional complexity was repeatedly added to the Enigma machines, making decryption more difficult and requiring further equipment and personnel—more than the Poles could readily produce.

On 26 and 27 July 1939, in Pyry near Warsaw, the Poles initiated French and British military intelligence representatives into their Enigma-decryption techniques and equipment, including Zygalski sheets and the cryptologic bomb, and promised each delegation a Polish-reconstructed Enigma. The demonstration represented a vital basis for the later British continuation and effort. During the war, British cryptologists decrypted a vast number of messages enciphered on Enigma. The intelligence gleaned from this source, codenamed "Ultra" by the British, was a substantial aid to the Allied war effort.

Though Enigma had some cryptographic weaknesses, in practice it was German procedural flaws, operator mistakes, failure to systematically introduce changes in encipherment procedures, and Allied capture of key tables and hardware that, during the war, enabled Allied cryptologists to succeed and "turned the tide" in the Allies' favor.