HMS Graph
   HOME

TheInfoList



OR:

HMS ''Graph'' (
pennant number In the Royal Navy and other navies of Europe and the Commonwealth of Nations, ships are identified by pennant number (an internationalisation of ''pendant number'', which it was called before 1948). Historically, naval ships flew a flag that iden ...
P715) was a German Type VIIC
U-boat U-boats are Submarine#Military, naval submarines operated by Germany, including during the World War I, First and Second World Wars. The term is an Anglicization#Loanwords, anglicized form of the German word , a shortening of (), though the G ...
captured and recommissioned by the British
Royal Navy The Royal Navy (RN) is the naval warfare force of the United Kingdom. It is a component of His Majesty's Naval Service, and its officers hold their commissions from the King of the United Kingdom, King. Although warships were used by Kingdom ...
during
World War II World War II or the Second World War (1 September 1939 – 2 September 1945) was a World war, global conflict between two coalitions: the Allies of World War II, Allies and the Axis powers. World War II by country, Nearly all of the wo ...
. Commissioned as ''U-570'' in
Nazi Germany Nazi Germany, officially known as the German Reich and later the Greater German Reich, was the German Reich, German state between 1933 and 1945, when Adolf Hitler and the Nazi Party controlled the country, transforming it into a Totalit ...
's ''
Kriegsmarine The (, ) was the navy of Nazi Germany from 1935 to 1945. It superseded the Imperial German Navy of the German Empire (1871–1918) and the inter-war (1919–1935) of the Weimar Republic. The was one of three official military branch, branche ...
'' in mid-1941, she was attacked and captured on her first patrol. She provided the Royal Navy and
United States Navy The United States Navy (USN) is the naval warfare, maritime military branch, service branch of the United States Department of Defense. It is the world's most powerful navy with the largest Displacement (ship), displacement, at 4.5 millio ...
with useful information about German submarines. Refitted for use by the Allies, she carried out three combat patrols with a Royal Navy crew, becoming the only U-boat to see active service with both sides during the war. She was withdrawn from service in 1944 due to problems maintaining her. While being towed to the breakers for scrapping, she ran aground on the Isle of Islay, off the west coast of
Scotland Scotland is a Countries of the United Kingdom, country that is part of the United Kingdom. It contains nearly one-third of the United Kingdom's land area, consisting of the northern part of the island of Great Britain and more than 790 adjac ...
. Some of the wreckage was removed as scrap but some remains to the present day.


Design and construction

The submarine was built to the German Type VIIC design. She had a
displacement Displacement may refer to: Physical sciences Mathematics and physics *Displacement (geometry), is the difference between the final and initial position of a point trajectory (for instance, the center of mass of a moving object). The actual path ...
of when surfaced, and when submerged. The boat was long, with a beam of , and a draught of . The diesel-electric propulsion system provided a maximum speed of surfaced or submerged. The ''U-570'' had a fuel capacity of which gave a range of at . The test depth of the submarine was . Her main armament consisted of five 53.3-cm (21-inch) torpedo tubes; four in the bow, and a fifth in the stern. She could carry a total of 14 torpedoes – five in the torpedo tubes, seven reloads inside the pressure hull, and a further two in water-tight canisters outside the pressure hull. The boat was fitted with an 8.8-cm C/35
deck gun A deck gun is a type of naval artillery mounted on the deck of a submarine. Most submarine deck guns were open, with or without a shield; however, a few larger submarines placed these guns in a turret. The main deck gun was a dual-purpose w ...
(with around 150 rounds of ammunition), and a 2-cm Flak 30 anti-aircraft gun with a 28-cm
stereoscopic rangefinder A stereoscopic rangefinder or stereoscopic telemeter is an optical device that measures distance from the observer to a target, using the observer's capability of binocular vision. It looks similar to a coincidence rangefinder, which uses differe ...
.CB 4318 p. 26 She also carried several machine guns.CB 4318 p. 5 Blohm & Voss laid down ''U-570'' at
Hamburg Hamburg (, ; ), officially the Free and Hanseatic City of Hamburg,. is the List of cities in Germany by population, second-largest city in Germany after Berlin and List of cities in the European Union by population within city limits, 7th-lar ...
on 21 May 1940. The submarine was launched on 20 March 1941.


Kriegsmarine service

''U-570'' was commissioned into the ''Kriegsmarine'' on 15 May 1941. After a series of short testing and commissioning trips in the Baltic, she moved to Norway where she carried out short training voyages and fired practice torpedoes. By 25 July, she had moved to the German U-boat base at Lofjord, part of
Trondheimsfjord The Trondheim Fjord or Trondheimsfjorden (), an inlet of the Norwegian Sea, is Norway's List of Norwegian fjords, third-longest fjord at long. It is located in the west-central part of the country in Trøndelag county, and it stretches from Ørl ...
, around north of Trondheim. In late August 1941, B-Dienst (the German naval codebreaking organisation) became aware of a large concentration of Allied merchant ships in the region of the North Atlantic south of Iceland. Admiral
Karl Dönitz Karl Dönitz (; 16 September 1891 – 24 December 1980) was a German grand admiral and convicted war criminal who, following Adolf Hitler's Death of Adolf Hitler, suicide, succeeded him as head of state of Nazi Germany during the Second World ...
ordered 16 U-boats to the area. ''U-570'' was to be one of these and, on the morning of 24 August, she put to sea on her first war patrol. Her planned mission was to patrol the area south of Iceland before proceeding to the U-boat base at La Pallice, France. She carried provisions for four weeks at sea. ''Kapitänleutnant'' Hans-Joachim Rahmlow commanded ''U-570''. He was an experienced naval officer, but had only recently transferred to U-boats, having previously been a gunnery and coastal defence specialist.CB 4051, p. 2 He had commanded the training submarine , but had carried out no war patrols. Likewise, the First Watch Officer (second-in-command) had only served a few months with the U-boat branch, after serving on destroyers, and the Second Watch Officer had little experience, having only recently been commissioned. The engineer was the only officer (and one of only four crewmen) who had served on a U-boat war patrol. While the boat's petty officers had several years of navy service, many of the enlisted crew were still new to the German navy and had only a few months of U-boat training. ''U-570''s inexperienced crew was not unique for the time. British interrogation of rescued crew-members of —sunk on her first patrol in September 1941—revealed that 41 out of 48 crew were on their first war patrol.


Capture

On 27 August 1941, ''U-570'' spent much of the morning submerged. She had been four days at sea and this was to give respite to a crew that was suffering acutely from seasickness (several had been incapacitated). Earlier that morning, a Lockheed Hudson bomber of 269 Squadron, RAF, flown by Sergeant Mitchell and operating from Kaldaðarnes, Iceland, had attacked her. The attack failed when the Hudson's bomb-racks failed to release its depth charges. ''U-570'' surfaced at position at around 10:50 am, immediately below a second 269 Squadron Hudson, flown by Squadron Leader James Thompson. Thompson was patrolling the area after Mitchell summoned him by radio. Rahmlow, who had climbed out onto the bridge, heard the approaching Hudson's engines and ordered a crash-dive. Thompson's aircraft reached ''U-570'' before she was fully submerged and dropped its four depth charges—one detonated just from the boat.CB 4051, p. 6 ''U-570'' quickly resurfaced and around 10 of the crew emerged. The Hudson fired on them with machine guns, but ceased when the U-boat crew displayed a white sheet. The captured crew members later recounted to British naval intelligence interrogators what had happened—the depth charge explosions had almost rolled the boat over, knocked out all electrical power, smashed instruments, caused water leaks, and contaminated the air on the boat. The inexperienced crew believed the contamination to be
chlorine Chlorine is a chemical element; it has Symbol (chemistry), symbol Cl and atomic number 17. The second-lightest of the halogens, it appears between fluorine and bromine in the periodic table and its properties are mostly intermediate between ...
, caused by acid from
leaking A leak is a way (usually an opening) for fluid to escape a container or fluid-containing system, such as a Water tank, tank or a Ship, ship's Hull (watercraft), hull, through which the contents of the container can escape or outside matter can e ...
battery cells mixing with sea-water, and the engine-compartment crew panicked and fled forward to escape the gas. Restoring electrical power—for the underwater electric motors and for lighting—would have been straightforward, yet there was nobody remaining in the engine compartment to do this.Blair 1996, p. 342 The submarine was dead in the water and in darkness. Rahmlow believed the chlorine would make it fatal to stay submerged so he resurfaced. The sea was too rough for the crew to man their anti-aircraft gun so they displayed a white flag to forestall another, probably fatal, depth charge attack from the Hudson—they were unaware the aircraft had dropped all its depth charges. Most of the crew remained on the deck of the submarine as Thompson circled above them, his aircraft now joined by a second Hudson that had been en route from Scotland to Iceland and had broken off its journey to lend assistance.The Imperial War Museum's collection includes
recorded interview
of former RAF Flying Officer Hugh Eccles, who was one of the crew of this aircraft.
A radio request for help saw a Consolidated Catalina flying boat of 209 SquadronThe aircraft was Catalina number ''AH553'', flown by Flying Officer Edward Jewiss; see; Conyers Nesbit (2008), p.74. Jewiss had been partially responsible for sinking the two days earlier. See: Blair (1996), p.342.Conyers Nesbit 2008, p.74 being scrambled at
Reykjavík Reykjavík is the Capital city, capital and largest city in Iceland. It is located in southwestern Iceland on the southern shore of Faxaflói, the Faxaflói Bay. With a latitude of 64°08′ N, the city is List of northernmost items, the worl ...
; it reached the scene three hours later. The German crew radioed their situation to the German naval high-command, destroyed their radio, smashed their
Enigma machine The Enigma machine is a cipher device developed and used in the early- to mid-20th century to protect commercial, diplomatic, and military communication. It was employed extensively by Nazi Germany during World War II, in all branches of the W ...
, and dumped its parts overboard along with the boat's secret papers. Admiral Dönitz later noted in his war diary that he ordered U-boats in the area to go to ''U-570''s assistance after receiving this report; responded, but Allied air patrols prevented ''U-82'' from reaching ''U-570''. ''U-570''s transmission was in plain language and the British intercepted it. Admiral Percy Noble, commander of Western Approaches Command, immediately ordered several ships to race to the scene. By early afternoon, fuel levels had forced the Hudsons to return to Iceland. The Catalina, a very long-range aircraft, was ordered to watch the submarine until Allied ships arrived. If none came before sunset, the aircraft was to warn ''U-570''s crew to take to the water, then sink her. The first vessel to reach ''U-570'', the anti-submarine trawler HMT ''Northern Chief'', arrived around 10:00 pm, guided to the scene by flares the Catalina dropped. The Catalina returned to Iceland after having circled ''U-570'' for 13 hours. The German crew remained on board ''U-570'' overnight; they made no attempt to scuttle their boat as ''Northern Chief'' had signalled she would open fire and not rescue survivors from the water if they did this. (''Northern Chief''s captain, N.L. Knight, had been ordered to prevent the submarine from being scuttled by any means.) During the night, five more Allied vessels reached the scene: the armed trawler ''Kingston Agate'', two anti-submarine whalers,The lake-class armed whalers HMS ''Wastwater'' and HMS ''Windermere'' the Royal Navy destroyer , and the Canadian destroyer . At daybreak, the Allies and Germans exchanged signal lamp messages, with the Germans repeatedly requesting to be taken off as they were unable to stay afloat, and the British refusing to evacuate them until the Germans secured the submarine and stopped it from sinking—the British were concerned that the Germans would deliberately leave behind them a sinking U-boat if they were evacuated. The situation became more confused when a small float-plane appeared: a Northrop N-3PB of 330 (Norwegian) Squadron).Dunmore, p. 129 Unaware of the surrender, it attacked ''U-570'' with small bombs and fired on ''Northern Chief'', which fired back. No damage was done and ''Burwell'' ordered the aircraft away by radio. The weather worsened; several attempts to attach a tow-line to ''U-570'' were unsuccessful. Believing the Germans were being obstructive, ''Burwell's'' captain, S.R.J. Woods ordered a machine gunner to fire warning shots, shots that accidentally hit and slightly wounded five of the German crew. With much difficulty, an officerLieutenant H.B. Campbell, ''see Conyers Nesbit 2008, p.75'', ''Blair 1996, p. 344'' and three sailors from ''Kingston Agate'' reached the submarine using a Carley float (a liferaft). After a quick search failed to find the U-boat's Enigma machine, they attached a tow line and transferred the five wounded men and the submarine's officers to ''Kingston Agate''. The remaining crew were taken on board HMCS ''Niagara'', which by this time had come alongside ''U-570''. The ships began slowly sailing to Iceland with ''U-570'' under tow, and with a relay of Hudsons and Catalinas constantly patrolling overhead. They arrived at dawn on 29 August at
Þorlákshöfn Þorlákshöfn (, ) is a town on the southern coast of Iceland in the Municipality of Ölfus. The town is named after Saint Thorlak who was a bishop at Skálholt. Its main importance is as a port as it has the only harbour on Iceland's southern c ...
. There, they beached ''U-570'' as she had been taking on water and was thought to be in danger of sinking.


Salvage and repair

Two days after ''U-570''s arrival, a British submarine commander—Lieutenant George Robson Colvin—together with a team of engineering warrant officers and civilian technical experts, arrived at Þorlákshöfn from Britain. They then carried out the initial examination and salvage of ''U-570''. Colvin's team was able to restore lighting and buoyancy; a refloated ''U-570'' was towed around the coast to the British naval base at
Hvalfjörður Hvalfjörður (, "whale fjord") is situated in the west of Iceland between Mosfellsbær and Akranes. The fjord is approximately long and wide. The origin of the name Hvalfjörður is uncertain. Certainly today there is no presence of whales i ...
. There ''U-570'' was docked to the depot ship HMS ''Hecla'' for repair, with the aim that ''U-570'' could make the trip to Britain under her own power.CB4318, Appendix 1, p. 50 The British discovered that the depth charge damage to the U-boat was not critical—there were leaks in some of the ballast tanks and a small leak in a fuel tank. Around one third of the battery cells were cracked and the bow had been buckled. Water had leaked in through a valve that had been unseated by the explosions and through glass gauges that had broken; other damage was minor and no evidence of chlorine gas found. In his report, Colvin stated his opinion that there was no evidence of any damage control being carried out and that an experienced submarine crew would have been easily able to improvise repairs, stay submerged and likely evade the air-attack. After their surrender, the German crew had attempted to destroy instruments and fittings, but, with the exception of the wrecked radio and the damaged torpedo firing computer, the attempt appeared half-hearted and the damage was not significant. Also, useful papers had missed destruction. Copies of encrypted signals and their corresponding, plain-language, German texts were found—material of use to the British Enigma code breaking effort.Sebag-Montefiore p. 162 A significant discovery was the U-boat commander's handbook, which provided context and background information for decrypted messages. The British, unfamiliar with German naval procedures, abbreviations and jargon, had often found German naval traffic hard to understand even when decrypted. ''U-570'' spent three weeks at Hvalfjörður, being repaired and taking short sea trials to test the engines and steering. Between 23 and 26 September, she was carefully inspected by two US Navy officers who had been sent from the United Kingdom to Iceland for that purpose; one of the submarine's G7a torpedoes was off-loaded, handed over to the Americans, and later sent to the United States. An eyewitness recalled that at one point, a Hudson bomber flew low over ''U-570'' and HMS ''Hecla'', signalling with a Morse lamp, "This ****** is mine." On 29 September, the submarine set out for the UK, manned by a Royal Navy
prize crew A prize crew is the selected members of a ship chosen to take over the operations of a captured ship. History Prize crews were required to take their prize to appropriate prize courts, which would determine whether the ship's officers and crew h ...
under the command of Lieutenant Colvin. Escorted by the S class destroyer HMS ''Saladin'' and HMS ''Kingston Agate'', she sailed on the surface as her diving planes had been damaged by the beaching at Þorlákshöfn. Her arrival at
Barrow-in-Furness Barrow-in-Furness is a port town and civil parish (as just "Barrow") in the Westmorland and Furness district of Cumbria, England. Historic counties of England, Historically in the county of Lancashire, it was incorporated as a municipal borou ...
on 3 October was filmed by Pathé News newsreel cameras, and reported in the press. The capture would later be featured in British propaganda. The capture of several other U-boats, such as the , which had sunk whilst under tow, was kept secret to conceal the seizure of their code-books and
Enigma machine The Enigma machine is a cipher device developed and used in the early- to mid-20th century to protect commercial, diplomatic, and military communication. It was employed extensively by Nazi Germany during World War II, in all branches of the W ...
s. ''U-570''s situation had been reported to the German high command. Also, so many ships, aircraft, and personnel had been involved in her capture that any attempt at secrecy would have been futile. ''U-570'' was placed in a dry-dock in the
Vickers Vickers was a British engineering company that existed from 1828 until 1999. It was formed in Sheffield as a steel foundry by Edward Vickers and his father-in-law, and soon became famous for casting church bells. The company went public in 18 ...
shipyard in Barrow. Her repair was complicated by depth-charge damage to her bow—her plating had been buckled, trapping four electrically powered
torpedo A modern torpedo is an underwater ranged weapon launched above or below the water surface, self-propelled towards a target, with an explosive warhead designed to detonate either on contact with or in proximity to the target. Historically, such ...
es in their torpedo tubes. Two officers from the Royal Navy's Department of Torpedoes and Mines Investigations had the task of retrieving them for examination. The dock was evacuated while a volunteer shipyard worker cut the armed torpedoes free with an oxyacetylene cutter under the officers' supervision. One of the officers—Lt Martin Johnson—then removed the magnetic pistols (detonators) from the torpedoes and made them safe—a dangerous task as the pistols were sensitive mechanisms and large enough to produce a lethal explosion on their own. For this act he was awarded the
George Medal The George Medal (GM), instituted on 24 September 1940 by King George VI,''British Gallantry Medals'' (Abbott and Tamplin), p. 138 is a decoration of the United Kingdom and Commonwealth of Nations, Commonwealth, awarded for gallantry, typically ...
on 8 December 1942. Squadron Leader Thompson, his navigator/bomb-aimer— Flying Officer John Coleman, and Flying Officer Edward Jewiss (the pilot of the 209 Squadron Catalina), all received the Distinguished Flying Cross on 23 September 1941. The captain of ''Kingston Agate'', Henry L'Estrange, was awarded the Distinguished Service Cross for his part in the capture.


German response

Initially, all the German naval high command knew of ''U-570''s situation was her radio message, saying she was under air-attack and unable to submerge; they only learned of her capture from later British press reports. They were concerned for the security of their communications and '' Vizeadmiral'' Erhard Maertens, the Director of the Naval Intelligence Command, was ordered to report on this. He concluded that in the worst-case scenario—that is, the British had secured ''U-570''s codebooks and Rahmlow had revealed to them his memorised, secret keyword—communications would be compromised until a new list of Enigma machine settings came into force in November. However, he believed this worst case to be unlikely and that ''U-570''s crew would have almost certainly destroyed their secret material. Even if they had not, the additional security of the commander's secret keyword would defeat British cryptanalysis.Sebag-Montefiore p. 163 In fact, the British code-breakers at
Bletchley Park Bletchley Park is an English country house and Bletchley Park estate, estate in Bletchley, Milton Keynes (Buckinghamshire), that became the principal centre of Allies of World War II, Allied World War II cryptography, code-breaking during the S ...
found the extra security of the keyword procedure to be simply of "nuisance value".Sebag-Montefiore p. 164 ''U-570''s crew had indeed destroyed their Enigma machine and code-books but the Germans were unaware of the Royal Navy's earlier capture of 's secret material, thanks to which the British had been breaking German naval cyphers since June 1941. British code-breaking was not seriously impeded until February 1942, when a new naval Enigma cypher remained unbroken for 10 months—the so-called "Shark Blackout". Apart from Rahmlow, ''U-570''s officers were taken to an officers' prisoner-of-war camp at Grizedale Hall in
Cumbria Cumbria ( ) is a ceremonial county in North West England. It borders the Scottish council areas of Dumfries and Galloway and Scottish Borders to the north, Northumberland and County Durham to the east, North Yorkshire to the south-east, Lancash ...
.Blair 1996, p. 347. This was nicknamed ''U-boat Hotel'' by the British as, during the early part of the war, the majority of prisoners were naval officers rescued from sunken U-boats. There, a " Court of Honour" convened by other German prisoners, including captured U-boat ace Otto Kretschmer, tried Rahmlow, ''in absentia'', and ''U-570''s other officers. Rahmlow and his second-in-command, Bernhard Berndt, were found "guilty of cowardice"; the other two officers were "acquitted". On the night of 18/19 October, Berndt escaped from the camp. A detachment of the
Home Guard Home guard is a title given to various military organizations at various times, with the implication of an emergency or reserve force raised for local defense. The term "home guard" was first officially used in the American Civil War, starting ...
apprehended him, shooting him when he tried to escape. According to some sources, he had escaped from the camp with the stated intention of redeeming himself by making his way to ''U-570''s dockyard at Barrow–a distance of only –and somehow destroying her. Another source states he was forced to make an escape attempt by a group of senior German prisoners who enforced a brutal regime of punishing those who held anti-Nazi views or who co-operated with the British, and that Berndt only broke away and ran from the Home Guard when he realised they were returning him to Grizedale Hall; they shot him dead after he ignored warning shots. The British placed Rahmlow in a camp with German Army and Air Force prisoners to avoid further incidents of this kind.These events may have formed the basis for the 1970 film '' The McKenzie Break'', in which a German PoW, played by Horst Janson, is victimised by his fellow prisoners in a Scottish PoW camp, while others escape and are subsequently recaptured. The German high command recognised ''U-570''s loss could be partially blamed on the crew's lack of training and experience (during the early part of the war, U-boat training had been cut down to two months).Mulligan (2011), p.79 Both this and mounting U-boat losses, including many boats sunk on their first patrol, prompted the Germans to put more resources into training. Also, the Germans broke up existing veteran crews and dispersed the men amongst the U-boat fleet, so the crews of all newly commissioned boats would include a core of experienced, long-serving crewmen. Months later, the German command was still trying to discover the fate of ''U-570''s codebooks. A system of coded messages, hidden in the text of apparently ordinary, personal letters, was used to order Otto Kretschmer to report on this. They were unaware that the Allies had discovered this channel of communication with German prisoners.


Royal Navy service

The disposition of ''U-570'' was initially uncertain.
Winston Churchill Sir Winston Leonard Spencer Churchill (30 November 1874 – 24 January 1965) was a British statesman, military officer, and writer who was Prime Minister of the United Kingdom from 1940 to 1945 (Winston Churchill in the Second World War, ...
was in favour of handing her over to the Americans for repair, both for propaganda and as a means of deepening then-neutral America's engagement in the
Battle of the Atlantic The Battle of the Atlantic, the longest continuous military campaign in World War II, ran from 1939 to the defeat of Nazi Germany in 1945, covering a major part of the naval history of World War II. At its core was the Allies of World War II, ...
. The Americans were eager to have her, but the Royal Navy objected both to this and to Churchill's other idea – to have her serve in the Mediterranean with a Yugoslav crew. Instead, she was commissioned into the Royal Navy as HMS ''Graph'' on 5 October 1941, and assigned the Royal Navy pennant number P715. She was given a name beginning with a 'G' to signify ''German'', i.e., denoting that ''Graph'' was a captured vessel. The name Graph was also chosen owing to the extensive testing carried out on her (and therefore the many "Graphs" drawn up), but was also a play on the German word ''Graf'' meaning "Count".


Trials

Once seaworthy, meticulous trials were conducted to measure every aspect of ''Graph''s sailing and diving characteristics. Even the Zeiss binoculars found on board were carefully tested. ''Graph''s safe diving depth was discovered to be —much deeper than the British thought for this kind of boat. At the time, Royal Navy depth charges had a maximum depth setting of so the Germans could dive out of their reach. Depth charges were soon modified to take account of this. The boat's acoustic and magnetic characteristics were examined by different Admiralty research establishments. The Allied technical experts found much to praise about her design and construction. ''Graph''s auxiliary machinery was on rubber mountings, making her stealthier by reducing sound transmission into the hull. The British and the Americans who examined ''Graph'' singled out her Zeiss periscope for particular praise. The American officers who carried out her initial inspection in Iceland recommended it be copied as quickly as possible for possible US Navy use. Her underwater acoustic equipment was found to be a sophisticated array of
hydrophone A hydrophone () is a microphone designed for underwater use, for recording or listening to underwater sound. Most hydrophones contains a piezoelectric transducer that generates an electric potential when subjected to a pressure change, such as a ...
s that was significantly better than the British equivalents.Blair 1996, p. 346. The main criticism of the boat was poor and cramped crew accommodation, which would degrade crew performance on long patrols. In mid-1942, ''Graph'' was carefully studied by the US Navy, which then had an interest in a new, smaller submarine that would be roughly her size – around two-thirds the length and half the displacement of the ''Gato''-class boats that formed the bulk of the US submarine fleet. She was considered superior in many ways to the two experimental ''Mackerel''-class, the existing class of small US submarine, but the project was dropped. Full-scale models of her pressure hull were constructed, and used during mid-1942 for underwater tests of experimental shaped charge anti-submarine bombs. In a highly secret British project, ''Graph'' was also used as a model for the construction of three, full-sized, mock-ups of the control compartment, wardroom and radio room of a Type VII U-boat. These were used to train specialist groups of sailors, who would form boarding parties whenever a damaged U-boat was blown to the surface. They were trained to operate a U-boat's ballast-tank valves, to reverse any scuttling attempts by the crew, and to search quickly for cryptographic equipment and documents.


Active service

After completing trials under the command of Lieutenant Commander E.D. Norman, ''Graph'' was placed under the command of Lieutenant Peter Barnsley Marriott, who had assisted in the trials. She departed from
Holy Loch The Holy Loch () is a sea loch, part of the Firth of Clyde, in Argyll and Bute, Scotland. The "Holy Loch" name is believed to date from the 6th century, when Saint Munn landed there after leaving Ireland. Kilmun Parish Church and Argyll Mausole ...
for her first Royal Navy war patrol on 8 October 1942, with the intention of patrolling the
Bay of Biscay The Bay of Biscay ( ) is a gulf of the northeast Atlantic Ocean located south of the Celtic Sea. It lies along the western coast of France from Point Penmarc'h to the Spanish border, and along the northern coast of Spain, extending westward ...
. On the afternoon of 21 October 1942, about north-north-east of Cape Ortegal (), ''Graph'' dived to evade a German
Focke-Wulf Fw 200 The Focke-Wulf Fw 200 ''Condor'', also known as ''Kurier'' (German language, German for ''courier'') to the Allies of World War II, Allies, is an all-metal four-engined monoplane designed and produced by the German aircraft manufacturer Focke-Wul ...
long-range patrol aircraft. A loud hydrophone contact made Marriott believe a nearby submarine had likewise dived and, 12 minutes later, he observed its conning-tower against the setting sun. After pursuing the German boat, ''Graph'' fired four torpedoes. Explosions were heard, and also banging noises, leading the British to believe they had hit the other submarine and the banging noises were caused by her breaking up as she sank.Terrell (1958), p. 146 In early 1943, Marriott was awarded the
Distinguished Service Order The Distinguished Service Order (DSO) is a Military awards and decorations, military award of the United Kingdom, as well as formerly throughout the Commonwealth of Nations, Commonwealth, awarded for operational gallantry for highly successful ...
for "great courage, skill and determination in a successful submarine patrol". After the war, examination of German records showed the submarine attacked was the , badly damaged after being rammed by the Flower-class corvette HMS ''Crocus'' off the coast of West Africa. German lookouts had seen the torpedoes' tracks, enabling ''U-333'' to evade the torpedoes; the torpedoes then self-detonated for unknown reasons. The commander of ''U-333'' was
Peter-Erich Cremer Peter-Erich Cremer (25 March 1911 – 5 July 1992) was a German U-boat commander during the Second World War. He was a recipient of the Knight's Cross of the Iron Cross of Nazi Germany. Biography Peter-Erich Cremer was born in Metz, Alsace-Lorr ...
. In his post-war account of the attack, he suggested the rattling and banging noises ''Graph''s crew had heard were due to the severe damage previously inflicted on ''U-333''. His route back to France closely hugged the Spanish coastline, a pattern followed by other U-boats, and he had also believed that Marriott was aware of this and had been lying in wait. ''Graph's'' second war patrol was from 19 November 1942 to 8 December 1942, also in the Bay of Biscay. During the patrol, she was ordered to intercept the Italian cargo ship ''Cortellazzo'', which was passing through the area ''en route'' from Bordeaux to Japan with a cargo of 2000 tons of machinery. However, ''Graph'' failed to find the ship and the patrol was without incident. ''Cortellazzo'' was sunk within days by HMS ''Redoubt'', one of the destroyer escorts of an Allied troop convoy, after ''Redoubt'' had ordered ''Cortellazzo''s crew to abandon ship and had picked them up. ''Graph'' departed from
Lerwick Lerwick ( or ; ; ) is the main town and port of the Shetland archipelago, Scotland. Shetland's only burgh, Lerwick had a population of about 7,000 residents in 2010. It is the northernmost major settlement within the United Kingdom. Centred ...
on her third war patrol on 24 December 1942 with three other Royal Navy submarines; their task was to patrol the waters off the coast of Norway in the area of Altafjord. At 1am on 1 January 1943, at the position , she sighted the German heavy cruiser ''Admiral Hipper'', returning from the unsuccessful attack on convoy JW 51B, better known as the Battle of the Barents Sea. ''Hipper'' was too far off and travelling too fast to be attacked.Terrell (1958), p. 147 At 4:23am, ''Graph'' sighted two German destroyers moving erratically and at low speed.Six German destroyers took part in the Battle of the Barents Sea; one was sunk. ''Graph'' closed to a range of and fired four torpedoes. Again, explosions convinced the British that hits had been scored and a destroyer probably sunk, but again all the shots had missed. ''Graph'' returned to Lerwick on 13 January 1943. ''Graph'' undertook no further war patrols. In 1943, she was assigned for training duties and command of her passed to Lt. D. Swanston. Peter Marriott went on to command , where he was awarded a
DSC DSC or Dsc may refer to: Education * Doctor of Science (D.Sc.) * District Selection Committee, an entrance exam in India * Doctor of Surgical Chiropody, superseded in the 1960s by Doctor of Podiatric Medicine Educational institutions * Dyal Sin ...
.


Decommissioning

Defects, exacerbated by a shortage of spare parts, led to ''Graph'' being placed in reserve. Also, her batteries and her
MAN A man is an adult male human. Before adulthood, a male child or adolescent is referred to as a boy. Like most other male mammals, a man's genome usually inherits an X chromosome from the mother and a Y chromosome from the f ...
diesel engine The diesel engine, named after the German engineer Rudolf Diesel, is an internal combustion engine in which Combustion, ignition of diesel fuel is caused by the elevated temperature of the air in the cylinder due to Mechanics, mechanical Compr ...
s had a comparatively short service life; German submarine batteries required annual replacement, unlike British batteries, which were intended to last for the lifetime of the boat. She was decommissioned from active service on 21 June 1943. She saw some use as a target, to determine the damage caused by depth charges in full-scale trials. After surviving these experiments, she was to be towed by the Royal Navy rescue tug HMRT ''Growler'' from Chatham to the Clyde for scrapping. But on 20 March 1944 her tow–rope broke in gale-force winds and, driven by wind and waves, she ran aground at a position , near Coul Point, on the west coast of
Islay Islay ( ; , ) is the southernmost island of the Inner Hebrides of Scotland. Known as "The Queen of the Hebrides", it lies in Argyll and Bute just south west of Jura, Scotland, Jura and around north of the Northern Irish coast. The island's cap ...
, Scotland. ''Growler'' was unable to re-float the submarine and she was abandoned. ''Graph'' was partially salvaged and scrapped in 1961. In 1966, the salvage diver Keith Jessop and others removed some more of the wreck, without the permission of the owner of the wreck's salvage rights; they paid £400 in compensation to the owner, but were still prosecuted and fined £50. Some remains of HMS ''Graph'' still remained visible at low tide on the rocks near Saligo beach in 1970, with the pressure casing of the conning tower and periscope tube visible (the cladding, railings and other parts had all broken off in the Atlantic storms many years before). Today, the remains of the wreck lie in about of water; the site has been visited and photographed by recreational divers. One of the ''Kriegsmarine'' battle flags of ''U-570'' was presented to Squadron Leader Thompson and is now part of the collection of the RAF Museum. Other surviving relics from the boat include her typewriter, held by the museum at
Bletchley Park Bletchley Park is an English country house and Bletchley Park estate, estate in Bletchley, Milton Keynes (Buckinghamshire), that became the principal centre of Allies of World War II, Allied World War II cryptography, code-breaking during the S ...
, a small
celestial globe Celestial globes show the apparent positions of the stars in the sky. They omit the Sun, Moon, and planets because the positions of these bodies vary relative to those of the stars, but the ecliptic, along which the Sun moves, is indicated. ...
used for navigation, that is owned by a private collector, and a German sailor's cap, that was taken as a souvenir by one of the officers of HMCS ''Niagara'' and is in the
Canadian War Museum The Canadian War Museum (CWM) () is a National museums of Canada, national museum on the military history of Canada, country's military history in Ottawa, Ontario, Canada. The museum serves as both an educational facility on Canadian military hist ...
. Another battle flag is claimed to have come into the possession of a young apprentice fitter at the Vickers Barrow shipyard and still survives.While it is quite possible the apprentice fitter was the volunteer who cut the torpedoes free and the flag was his reward, the sources do not explicitly confirm this.


See also

* List of submarines of the Second World War * – Formerly, the experimental,
German Type XVII submarine The Type XVII U-boats were small coastal submarines that used a high-test peroxide propulsion system, which offered a combination of air-independent propulsion and high submerged speeds. Background In the early 1930s Hellmuth Walter had designe ...
''U-1407''; used by the Royal Navy post-war. * – Royal Navy submarine, captured and taken into service by the Germans. * – Italian submarine captured and taken into service by the Royal Navy. * – German Type VII-C/41 U-boat that was commissioned as the Royal Navy submarine ''N2'' between 1945 and 1946.


Notes


References


Bibliography


"ADM 186/806—CB 4051 ''U 570, Interrogation of Crew''"
Intelligence Division Naval Staff, Admiralty. January 1941. Now in The National Archives an
reproduced in full
by uboatarchive.net * * * * * *: The memoir of a Royal Navy submariner who served on ''Graph'' * *: See chapter VIII in which the author describes joining Lieutenant Martin Johnson at Barrow to work out how to access the torpedoes. * * * * *


External links



269 Squadron RAF Website. A 1956 article from the German magazine ''Kristall'', translated by Gerry Raffé. Includes an account of Bernhard Berndt's prison camp escape and Rahmlow's own description of the circumstances of the boat's surrender.

269 Squadron RAF Website, Pictures of the U-570's capture and her beaching at ?orlákshöfn. * {{DEFAULTSORT:Graph (P715) Ships built in Hamburg German Type VIIC submarines German submarine U-570 Submarines of the Royal Navy German submarine U-570 German submarine U-570 1941 ships Naval ships of Germany captured by the United Kingdom during World War II Maritime incidents in August 1941 Maritime incidents in March 1944