The Mansion. Photo: © the2xislesteam The Enigma cipher was the backbone of German military and intelligence communications. First invented in 1918, it was designed to secure banking communications where it achieved little success. However the German military were quick to see its potential, they thought it to be unbreakable, and not without good reason. Enigma's complexity was bewildering. The odds against anyone who did not know the settings being able to break Enigma were a staggering 150 million, million, million, to one. Back in 1932 the Poles had broken Enigma, at a time when the encoding machine was undergoing trials with the German Army., the Poles even managed to reconstruct a machine. At that time, the cipher altered every few months but with the advent of war it changed at least once a day effectively locking the Poles out. July 1939, the Poles had passed on their knowledge to the British and the French. This enabled the code-breakers to make critical progress in working out the order in which the keys were attached to the electrical circuits, a task that had been impossible without an Enigma machine in front of them. Armed with this knowledge, the code-breakers were then able to exploit a chink in Enigma's armour. A fundamental design flaw meant that no letter could ever be encrypted as itself; an A in the original message, for example, could never appear as an A in the code. This gave the code breakers a toehold. Errors in messages sent by tired, stressed or lazy German operators also gave clues. In January 1940 came the first break into Enigma. It was in Huts 3,6,4 and 8 that the highly effective Enigma decrypt teams worked. The huts operated in pairs and, for security reasons, were known only by their numbers. Hut 8 decoded messages from the German Navy, with Hut 4 the associated naval intelligence hut. To speed up the code breaking process, the brilliant mathematician Alan Turing developed an idea originally proposed by Polish cryptanalysts. The result was the Bombe: an electro-mechanical machine that greatly reduced the odds, and thereby the time required, to break the daily-changing Enigma keys. Photos: © the2xislesteam Alan Turing 1912 – 1954 Mathematician & code breaker Naval Section – Hut 4 Hut 4 was built in 1939 and the Naval Section moved here from the Library early in 1940. Decrypted Enigma messages were sent here from Hut 8 to be translated and forwarded to the Naval Intelligence Division at the Admiralty. In 1942, Naval Section moved to Block A. Hut 4 was then used for Military, Intelligence Exchange and Wireless Transmission co-ordination until 1945. It is one of the largest Huts, the only Hut in the Park to have been in continuous use since it was built and has been repeatedly altered internally, since early days. Block A Hut 8 Alan Turing worked here, it is now a special exhibitions area. Hut 4 This is now a café. Photo: © the2xislesteam (Photographed from leaflet) Through this slideshow it is hoped to give a couple of brief accounts about machinery and documents seized by the Royal Navy. ACCOUNT 1 THE CAPTURE OF ENIGMA CODEBOOKS & ENIGMA MACHINE FROM U-BOAT110 ON MAY 9th 1941. The capture is noteworthy because the Enigma codebooks & machine seized were to play a significant role in the breaking of the naval Enigma code by the code breakers at Bletchley Park. Below are the three ships instrumental in the capture of U-Boat110. HMS Bulldog (Destroyer) HMS Aubretia (Corvette) HMS Broadway (Destroyer) Photos: Crown Copyright May 1941 SETTING THE SCENE OB 318, a west bound convoy of ships either in ballast or carrying trade goods, the convoy was sailing from Liverpool to ports in North America. They were escorted by 7th Escort Group consisting of ten warships. These were joined in mid-ocean by 3rd Escort Group, a force of eight warships led by HMS Bulldog. Opposing them was a force of nineteen U-boats, though in the event only six were in a position to pose a threat. LEADING UP TO THE ACTION OB 318 had been sighted on May 7th by one of the U-boats (U-94), its position was reported to U-boat command. Shadowing of the convoy continued until U-boat command alerted other U-boats within the area. It was found that six others were within striking distance, they were ordered to close with U-94’s position. Meanwhile during 7th May the escort force was joined by five ships from Iceland and the destroyers of 3 EG, which were to take over escort duties from the Western Approaches to a dispersal point at 34 West, a location south of Greenland. Three ships and the destroyers of 7 EG left for Iceland during 7 May, leaving the escort force still at ten warships. Nightfall on the 7th May U-94 attacked the convoy sinking two of their ships. However a counter attack (lasting four hours) was made against the U-boat, ships involved were, Rochester, Bulldog & Amazon, U-94 was damaged and retired for a short spell before resuming patrol. On 8th May the remaining vessels of 3 EG, three corvettes and two trawlers, with the Armed Merchant Cruiser Ranpura in company, joined the convoy, and the remaining ships of 7 EG departed. On the evening of 8th May U-110 & U-201 made contact and continued to shadow the convoy. The captains of the two U-boats had made a rendezvous in order to o-ordinate their attack in the belief that the Escort Group would have departed by morning leaving the convoy vulnerable to their assault. THE ATTACK AND COUNTER -ATTACK The morning of May 9th U-110 moved into position and began her attack. The captain of U-110 was surprised to find that the escort was still in place, however U-110 succeeded in penetrating the convoy and sank two of the ships. The counter-attack was vigorous, it involved the ships Aubretia (Corvette) Broadway & Bulldog (both destroyers), she was forced to the surface and abandoned. U-110 was still afloat and was captured by the three warships who dropped out of the convoy to secure their prize. Royal Naval personnel made several trips to U-110, ransacking it completely before starting to tow it back to Britain. Along the way they realised they had claimed one of the most important prizes of the war - a complete and un-sabotaged Enigma machine, along with secret papers. The captain of U-210 also made his attack, sinking one ship and damaging another. He was also counter-attacked by ships Amazon, Nigella and St Apollo, and forced to retire, damaged. In the early hours of the morning of May 10th, OB 318 was attacked by another U-boat and one ship was damaged. Over the next two weeks the remaining ships from OB 318 made landfall at various ports around the Atlantic. THE CONCLUSION The action round OB 318 was a qualified success, thirty three ships arrived at their destination. The capture of, intact, U-110 and her signal equipment, including an Enigma coding machine, with rotors and code-books. British intelligence realised that if word of U-110's capture got out, the Germans would change all their Enigma machines, updating their cryptography to ensure their communications remained secret. The order went out to the British convoy to scuttle the U-boat rather than bring it back to port, and so U-110 was sunk in the Atlantic. Maps of where the action took place. Photos: © the2xislesteam (Photographed at Bletchley Park) ACCOUNT 2 THE CAPTURE OF THE WETTERKURZSCHLÜSSEL AND KURZSIGNALHEFT FROM U-BOAT 559. The German Navy's three-rotor Enigma machine (M3) was identical to the model used by the German Army and Air Force, but it was supplied with three additional rotors, VI, VII and VIII, which were reserved exclusively for naval use. However, the German Navy also employed codebooks, which shortened signals as a precaution against shore high-frequency direction-finding, and some manual ciphers. The codebooks most often used were the Kurzsignalheft (short signal book) for reports such as sighting convoys, and the Wetterkurzschlüssel (weather short signal book) for weather reports. The relevant code-groups were super-enciphered on Enigma before being transmitted by radio. Photos: Crown Copyright The three men pivotal in the ‘capture of the Wetterkurzschlűssel and Kurzsignalheft. Lieutenant Anthony Fasson Able Seaman Colin Grazier NAAFI Assistant Tommy Brown All served on board HMS Petard THE SETTING On the 30th October 1942, U-559 was spotted by a Sunderland Patrol Aircraft approximately seventy miles north of the Nile Delta. HMS Hero (Destroyer) was alerted and steamed to intercept her, meanwhile destroyers HMS Petard, Pakenham, Dulverton and Hurworth sailed from Port Said. U-559 detected the approach of HMS Hero so decided to dive. The group hunted for the U-boat for several hours constantly depth charging them. After dark U-559 was forced to the surface with a cracked pressure hull, unable to maintain level trim, members of her crew dead from explosions and flooding. THE ACTION On surfacing the U-boat was close to HMS Petard which immediately open fired on her. The crew hurriedly scrambled overboard without destroying their codebooks or Enigma machine and crucially, failed to open sea-water vents to properly scuttle the U-boat. Three British sailors boarded U-boat, (there are varying accounts as to how these three men arrived at the U-boat). The three men concerned are: Lt Anthony Fasson, Able Seaman Colin Grazier and Tommy Brown NAAFI Assistant.