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The ''Blockhaus d'Éperlecques'' (, also referred to as "the Watten bunker" or simply "Watten") is a
Second World War 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 ...
bunker A bunker is a defensive military fortification designed to protect people and valued materials from falling bombs, artillery, or other attacks. Bunkers are almost always underground, in contrast to blockhouses which are mostly above ground. T ...
, now part of a museum, near
Saint-Omer Saint-Omer (; ; Picard: ''Saint-Onmé'') is a commune and sub-prefecture of the Pas-de-Calais department in France. It is west-northwest of Lille on the railway to Calais, and is located in the Artois province. The town is named after Sa ...
in the northern
Pas-de-Calais The Pas-de-Calais (, ' strait of Calais'; ; ) is a department in northern France named after the French designation of the Strait of Dover, which it borders. It has the most communes of all the departments of France, with 890, and is the ...
''département'' of France, and only some 14.4 kilometers (8.9 miles) north-northwest from the more developed
La Coupole ''La Coupole'' (), also known as the ''Coupole d'Helfaut-Wizernes'' and originally codenamed ''Bauvorhaben'' 21 ('Building Project 21') or ''Schotterwerk Nordwest'' (Northwest Gravel Works), is a Second World War bunker complex in the Pas-de-Cal ...
V-2 launch facility, in the same general area. The bunker, built by
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 ...
under the
codename A code name, codename, call sign, or cryptonym is a code word or name used, sometimes clandestinely, to refer to another name, word, project, or person. Code names are often used for military purposes, or in espionage. They may also be used in ...
Kraftwerk Nord West (Powerplant Northwest) between March 1943 and July 1944, was originally intended to be a launching facility for the V-2 (A-4)
ballistic missile A ballistic missile is a type of missile that uses projectile motion to deliver warheads on a target. These weapons are powered only during relatively brief periods—most of the flight is unpowered. Short-range ballistic missiles (SRBM) typic ...
. It was designed to accommodate over 100 missiles at a time and to launch up to 36 daily. The facility would have incorporated a
liquid oxygen Liquid oxygen, sometimes abbreviated as LOX or LOXygen, is a clear cyan liquid form of dioxygen . It was used as the oxidizer in the first liquid-fueled rocket invented in 1926 by Robert H. Goddard, an application which is ongoing. Physical ...
factory and a bomb-proof railway station to allow missiles and supplies to be delivered from production facilities in Germany. It was constructed using the labour of thousands of prisoners of war and forcibly conscripted workers used as slave labourers. The bunker was never completed as a result of the repeated bombing by the
British British may refer to: Peoples, culture, and language * British people, nationals or natives of the United Kingdom, British Overseas Territories and Crown Dependencies. * British national identity, the characteristics of British people and culture ...
and United States air forces as part of
Operation Crossbow ''Crossbow'' was the code name in World War II for Anglo-American operations against the German V-weapons, long range reprisal weapons (V-weapons) programme. The primary V-weapons were the V-1 flying bomb and V-2 rocket, which were launched agai ...
against the German V-weapons programme. The attacks caused substantial damage and rendered the bunker unusable for its original purpose. Part of the bunker was subsequently completed for use as a liquid oxygen factory. It was captured by Allied forces at the start of September 1944, though its true purpose was not discovered by the Allies until after the war. V-2s were instead launched from ''
Meillerwagen The ''Meillerwagen'' () was a German World War II trailer used to transport a V-2 rocket from the 'transloading point' of the Technical Troop Area to the launching point, to erect the missile on the ''Brennstand'' (), and to act as the Service to ...
''-based mobile batteries which were far less vulnerable to aerial attacks. The bunker is preserved as part of a privately owned museum that presents the history of the site and the German V-weapons programme. It has been protected by the French state as a since 1986.


Background

The A-4 ballistic missile (referred to as the V-2 from September 1944) was developed by the Germans between 1939 and 1944. It was regarded by
Adolf Hitler Adolf Hitler (20 April 1889 – 30 April 1945) was an Austrian-born German politician who was the dictator of Nazi Germany from 1933 until Death of Adolf Hitler, his suicide in 1945. Adolf Hitler's rise to power, He rose to power as the lea ...
as a '' Wunderwaffe'' (wonder weapon) that he believed to be capable of turning the tide of the war. Its operational deployment was restricted by several factors. Large supplies of cryogenic liquid oxygen (LOX) were required as the
oxidizer An oxidizing agent (also known as an oxidant, oxidizer, electron recipient, or electron acceptor) is a substance in a redox chemical reaction that gains or " accepts"/"receives" an electron from a (called the , , or ''electron donor''). In ot ...
to fuel the missiles. LOX evaporates rapidly, necessitating a source reasonably close to the firing site in order to minimise loss through evaporation. Germany and the occupied countries did not at that time have sufficient manufacturing capacity for the amount of LOX required for a full-scale A-4 campaign; the total production capacity in 1941 and 1942 was about 215 tons daily, but each A-4 launch required about 15 tons. As the missile was intended for use against London and southern England, its operational range of meant that the launch sites had to be located fairly close to the
English Channel The English Channel, also known as the Channel, is an arm of the Atlantic Ocean that separates Southern England from northern France. It links to the southern part of the North Sea by the Strait of Dover at its northeastern end. It is the busi ...
or southern
North Sea The North Sea lies between Great Britain, Denmark, Norway, Germany, the Netherlands, Belgium, and France. A sea on the European continental shelf, it connects to the Atlantic Ocean through the English Channel in the south and the Norwegian Se ...
coasts, in northern France, Belgium or the western Netherlands. This was within easy reach of the Allied air forces, so any site would have to be able to resist or evade the expected aerial bombardments. Various concepts were mooted for the A-4's deployment in a March 1942 study by Walter Dornberger, the head of the A-4 development project at the Peenemünde Army Research Center. He suggested that the missiles should be based in heavily defended fixed sites of a bunker-style design similar to the massive submarine pens then under construction in occupied France and Norway. The rockets could be stored in such sites, armed, fuelled from an on-site LOX production plant, and launched. This offered significant technical advantages; not only would the LOX loss be minimised, but the complex process of pre-launch testing would be simplified. A high rate of fire could be sustained as the facility could effectively operate like a production line, sending a steady flow of missiles to the launch pads. The submarine pens and other
Atlantic Wall The Atlantic Wall () was an extensive system of coastal defence and fortification, coastal defences and fortifications built by Nazi Germany between 1942 and 1944 along the coast of continental Europe and Scandinavia as a defense (military), d ...
fortifications had been built in 1940 and 1941, when the Germans had air superiority and could deter Allied air attacks. By 1942 this advantage had been lost to the
United States Army Air Forces The United States Army Air Forces (USAAF or AAF) was the major land-based aerial warfare service component of the United States Army and ''de facto'' aerial warfare service branch of the United States during and immediately after World War II ...
, which had begun deploying to England in May 1942, and a greatly expanded
Royal Air Force The Royal Air Force (RAF) is the Air force, air and space force of the United Kingdom, British Overseas Territories and Crown Dependencies. It was formed towards the end of the World War I, First World War on 1 April 1918, on the merger of t ...
. The
German Army The German Army (, 'army') is the land component of the armed forces of Federal Republic of Germany, Germany. The present-day German Army was founded in 1955 as part of the newly formed West German together with the German Navy, ''Marine'' (G ...
preferred an alternative approach which would use trailer-style mobile launch platforms called ''
Meillerwagen The ''Meillerwagen'' () was a German World War II trailer used to transport a V-2 rocket from the 'transloading point' of the Technical Troop Area to the launching point, to erect the missile on the ''Brennstand'' (), and to act as the Service to ...
'' accompanied by testing and fuelling equipment mounted on railway cars or trucks. Although this configuration was far less efficient and would have a much lower rate of fire, it would have the great advantage of presenting a much smaller target for the Allied air forces. The Army was not convinced that fixed bunkers could resist repeated air attacks and was particularly concerned about the vulnerability of the launch sites' road and rail links, which were essential for resupplying them with missiles and fuel. In November 1942, Hitler and Minister of Munitions
Albert Speer Berthold Konrad Hermann Albert Speer (; ; 19 March 1905 – 1 September 1981) was a German architect who served as Reich Ministry of Armaments and War Production, Minister of Armaments and War Production in Nazi Germany during most of W ...
discussed possible launch configurations and examined models and plans of the proposed bunkers and mobile launchers. Hitler strongly preferred the bunker option, though he also gave the go-ahead for the production of mobile launchers. Two different bunker designs had been prepared: the B.III-2a design envisaged preparing the missile for launch inside the bunker, then transporting it outside to a launch pad, while the B.III-2b design would see the missile being elevated from within the bunker to a launch pad on the roof. Speer gave orders that two bunkers were to be constructed by the
Organisation Todt Organisation Todt (OT; ) was a Civil engineering, civil and military engineering organisation in Nazi Germany from 1933 to 1945, named for its founder, Fritz Todt, an engineer and senior member of the Nazi Party. The organisation was responsible ...
construction group to a "special fortification standard" (''Sonderbaustärke''), requiring a steel-reinforced concrete ceiling thick and walls thick. They would be built near the coasts opposite England, one on the Côte d'Opale near
Boulogne-sur-Mer Boulogne-sur-Mer (; ; ; or ''Bononia''), often called just Boulogne (, ), is a coastal city in Hauts-de-France, Northern France. It is a Subprefectures in France, sub-prefecture of the Departments of France, department of Pas-de-Calais. Boul ...
and the other on the
Cotentin Peninsula The Cotentin Peninsula (, ; ), also known as the Cherbourg Peninsula, is a peninsula in Normandy that forms part of the northwest coast of France. It extends north-westward into the English Channel, towards Great Britain. To its west lie the Gu ...
near
Cherbourg Cherbourg is a former Communes of France, commune and Subprefectures in France, subprefecture located at the northern end of the Cotentin peninsula in the northwestern French departments of France, department of Manche. It was merged into the com ...
. Each would be capable of launching 36 missiles a day, would hold sufficient supplies of missiles and fuel to last three days, and would be manned by 250 troops.


Design and location

In December 1942, Speer ordered
Peenemünde Peenemünde (, ) is a municipality on the Baltic Sea island of Usedom in the Vorpommern-Greifswald district in Mecklenburg-Vorpommern in north-eastern Germany. It is part of the ''Amt (country subdivision), Amt'' (collective municipality) of Used ...
officers and engineers (including Colonel Gerhard Stegmair, Dr Ernst Steinhoff and Lieutenant-Colonel Georg Thom) to tour the
Artois Artois ( , ; ; Picard: ''Artoé;'' English adjective: ''Artesian'') is a region of northern France. Its territory covers an area of about 4,000 km2 and it has a population of about one million. Its principal cities include Arras (Dutch: ...
region in northwest France and locate a suitable site for an A-4 launch facility. The site chosen was just to the west of the small town of Watten, in the Forest of Éperlecques, near
Saint-Omer Saint-Omer (; ; Picard: ''Saint-Onmé'') is a commune and sub-prefecture of the Pas-de-Calais department in France. It is west-northwest of Lille on the railway to Calais, and is located in the Artois province. The town is named after Sa ...
in the
Pas-de-Calais The Pas-de-Calais (, ' strait of Calais'; ; ) is a department in northern France named after the French designation of the Strait of Dover, which it borders. It has the most communes of all the departments of France, with 890, and is the ...
department. It was given the cover name of ''Kraftwerk Nord West'' (Northwest Power Plant). The location was conveniently close to the main railway line between
Calais Calais ( , , traditionally , ) is a French port city in the Pas-de-Calais department, of which it is a subprefecture. Calais is the largest city in Pas-de-Calais. The population of the city proper is 67,544; that of the urban area is 144,6 ...
and Saint-Omer, the canalised river Aa, main roads and electric grid lines. Situated from London, it was far enough inland to be safe from naval guns and it was sheltered to an extent by a ridge that rises to a height of to the north. At nearby Saint-Omer, there was a major
Luftwaffe The Luftwaffe () was the aerial warfare, aerial-warfare branch of the before and during World War II. German Empire, Germany's military air arms during World War I, the of the Imperial German Army, Imperial Army and the of the Imperial Ge ...
base which was capable of providing air defence for the area. There were existing gravel and sand quarries as well as cement works in the vicinity, which would help with the enormous amount of material that would be needed for the construction works. The quantities required were very substantial indeed; 200,000 tons of concrete and 20,000 tons of steel would be required to build the facility. When US Army Major General Lewis H. Brereton inspected the site after it had been captured by the Allies, he described the bunker as "more extensive than any concrete constructions we have in the United States, with the possible exception of Boulder Dam." The Watten bunker was to be built to a design based on the B.III-2a bunker, though substantially larger. The Germans had originally planned to build a separate LOX plant at Stenay but this option was abandoned in favour of installing a LOX production facility within the Watten bunker. The bunker consisted of three main elements. The main part of the building was a giant structure some wide and high, housing the LOX plant and a vault where missiles would be assembled and prepared. Its walls were up to thick and the bunker's working levels descended below ground. The plant would house five Heylandt compressors, each capable of producing about 10 tons of LOX per day. About 150 tons of LOX were to be stored in insulated tanks on-site. The facility was intended to store up to 108 missiles and enough fuel to supply three days' worth of launches. The Germans planned to fire up to 36 rockets a day from the site. On the north side of the building was a fortified standard gauge railway station, linked to the main Calais-Saint-Omer line at Watten via a spur line. Missiles, warheads and other components would be shipped to the station and transported on trucks into the main area of the bunker. Here the rockets were to be assembled, raised into a vertical position and fuelled and armed. From the arming halls, they would be moved to either end of the building through pivoting doors high. They would exit through the south face of the building and would be moved on tracks to the launch pads. There were no doors on the exit portals so chicanes were installed in the exit passage to deflect the blast of rockets being launched from outside. Launches would be overseen from a command tower located in the centre of the south side of the bunker, overlooking the launch pads. To the north of the bunker, the Germans erected a bomb-proof power station with a generating capacity. The site was initially powered from the main electricity grid, but it was intended that it would have its own independent power source to minimise the likelihood of disruption. Also associated with the Watten complex was a radar tracking site at Prédefin, south of Saint-Omer. A Giant Würzburg radar system was installed there to follow the trajectories of V-2s being launched from Watten. The intention was to follow the trajectory for as long as possible so that the accuracy of the missile launches could be determined.


Construction

The site was designed in January and February 1943 by engineers from the Peenemünde research facility and the Organisation Todt. On 25 March 1943 the construction plans were presented to Hitler, who immediately gave the go-ahead for the project to begin. The construction firm Holzman & Polanski was awarded the contract and 6,000 workers from Building Battalion 434 started construction that same month using plans by Franz Xaver Dorsch, Construction Director at the Organisation Todt. It was envisaged that the structure would be ready by the end of July 1943, though not its wiring and plant, and it was intended that it would be fully operational by 1 November 1943. The workforce consisted of a mixture of German specialists and forcibly conscripted Frenchmen from the ''
Service du Travail Obligatoire The ' (STO; ) was the forced enlistment and deportation of hundreds of thousands of French workers to Nazi Germany to work as Forced labor in Germany during World War II, forced labour for the German war effort during World War II. The STO was ...
'' (STO). They were supplemented by Belgian, Dutch, French, Polish, Czech and Soviet prisoners of war and civilian conscripts, who were used as slave labour. The labour force also included many French political prisoners and Spanish Republicans who had fled to France after General Franco's victory in the
Spanish Civil War The Spanish Civil War () was a military conflict fought from 1936 to 1939 between the Republican faction (Spanish Civil War), Republicans and the Nationalist faction (Spanish Civil War), Nationalists. Republicans were loyal to the Left-wing p ...
but had then been interned by the invading Germans. The non-German workers lived in two camps officially known as Organisation Todt Watten ''Zwangsarbeitslager'' 62 (Forced Labour Camp 62) about distant from the site, near the village of Éperlecques. The camps were guarded by the French civil police with the assistance of Belgian and Dutch Nazis and Russian POWs who had volunteered for guard duty. Although escape attempts were punished by immediate execution, there were up to three escapes daily with external assistance. The commandant of the camp is said to have complained that it would have been easier to "guard a sack of fleas". Over 35,000 foreign workers passed through the camps during the period in which they were operational. The labourers worked in 12-hour shifts of 3,000–4,000 men, with three 20-minute breaks during each shift. The work continued around the clock, seven days a week, under giant floodlights during the night. The living and working conditions were extremely harsh, especially for the political prisoners and the eastern Europeans, who were given especially punitive treatment due to their status as the most expendable members of the workforce. For the non-German workers, falling ill or being unable to work through injury was the equivalent of a death sentence, as they would either be left to die or be transported back to the concentration camps from which they had been brought. A German commission that inspected the labour camps in the area in late 1943 commented: "The Eastern uropeanworker is very tough. He works at his job until he falls flat on his face in the mire, and all that is left for the doctor to do is to issue the death certificate." A large supply dump was established at Watten next to the River Aa. This site was eventually used to store material required for all the V-weapon sites in the Saint-Omer area. Building materials were brought there by barges and trains where they were unloaded onto a Decauville narrow-gauge railway for transportation to the construction site, where concrete mixers operated day and night. A 90 kV power line running to a transformer at Holque north of Watten provided electricity. An old quarry at
Wizernes Wizernes (; ) is a Communes of France, commune in the Pas-de-Calais department, northern France. It lies southwest of Saint-Omer on the banks of the river Aa (France), Aa at the D928 and D211 road junction. The commune is twinned with Ensdorf, ...
codenamed ' (Gravel Quarry Northwest), some south of Watten, was also converted into a storage dump to supply the Watten facility.


Discovery and Allied attacks

In early April 1943, an Allied agent reported "enormous trenches" being excavated at the Watten site, and on 16 May 1943 an RAF reconnaissance mission led to Allied photographic interpreters noticing unidentified activity there. Other large facilities were observed to be under construction elsewhere in the Pas-de-Calais. The purpose of the construction works was very unclear; Lord Cherwell,
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, ...
's scientific adviser, admitted that he had little idea what "these very large structures similar to gun emplacements" were but he believed that "if it is worth the enemy's while to go to all the trouble of building them it would seem worth ours to destroy them." At the end of May, the British Chiefs of Staff ordered that aerial attacks be carried out against the so-called "heavy sites" being built by the Germans. On 6 August, Duncan Sandys, who headed a high-level Cabinet committee to coordinate the British defence against the German V-weapons, recommended that the Watten site should also be attacked because of the progress being made in its construction. The British Chiefs of Staff noted that a daylight attack by US bombers was under consideration but they raised objections to the proposal, as the Air Staff thought that Watten had nothing to do with rockets, suggesting that instead it might be merely a "protected operations room". The timing of the first raid was influenced by advice given by Sir Malcolm McAlpine, the chairman of the construction company Sir Robert McAlpine, who suggested that the Watten site should be attacked while the concrete was still setting. On 27 August 1943, 187
B-17 Flying Fortress The Boeing B-17 Flying Fortress is an American four-engined heavy bomber aircraft developed in the 1930s for the United States Army Air Corps (USAAC). A fast and high-flying bomber, the B-17 dropped more bombs than any other aircraft during ...
es of the US 8th Air Force attacked the site with devastating effect. The fortified train station on the north side of the bunker was especially badly damaged, as concrete had just been poured there. Dornberger later wrote that following the attack the site was "a desolate heap of concrete, steel, props and planking. The concrete hardened. After a few days the shelter was beyond saving. All we could do was roof in a part and use it for other work." The bombing killed and injured hundreds of the slave workers on site; although the Allies had sought to avoid casualties by timing the raid with what they thought was a change of shifts, the shift pattern had been changed by the Germans at the last minute to achieve the day's work quota. Only 35% of the Watten bunker had been completed by this time."An Engineer Returns ... And A Museum Is Born", ''After the Battle'' 57:49–53. London: After the Battle Magazine It was clearly no longer possible to use it as a launch site, but the Germans still needed LOX production facilities to supply V-2 sites elsewhere. After surveying the site in September and October 1943, Organisation Todt engineers determined that the northern part of the facility was irretrievably damaged but decided to focus on completing the southern part to serve as a LOX factory. One of OT's engineers, Werner Flos, came up with an idea to protect the bunker from bombardment by building it up from the roof first. This was done by initially constructing a concrete plate, flat on the ground, which was thick and weighed 37,000 tons. It was incrementally raised by hydraulic jacks and then supported by walls which were built underneath it as it was raised, becoming the roof. The resulting concrete cavern was intended to be used by the Germans as a bombproof liquid oxygen factory. The thickness of the roof was chosen on the assumption that Allied bombs were incapable of penetrating such a depth of concrete; the Germans, however, were unaware of the British development of earthquake bombs. The Germans' main focus of attention switched instead to ''Schotterwerk Nordwest'', the former quarry at nearby Wizernes, where work had been ongoing to build a bombproof V-2 storage facility. This project was expanded to turn the quarry into a fixed launch facility. Plans were put into effect to build a huge concrete dome – now open to the public as the museum of
La Coupole ''La Coupole'' (), also known as the ''Coupole d'Helfaut-Wizernes'' and originally codenamed ''Bauvorhaben'' 21 ('Building Project 21') or ''Schotterwerk Nordwest'' (Northwest Gravel Works), is a Second World War bunker complex in the Pas-de-Cal ...
 – under which missiles would be fuelled and armed in a network of tunnels before being transported outside for launching. The Allies carried out further heavy bombing against both the Watten and Wizernes sites with little initial effect on the buildings themselves, although the rail and road network around them was systematically destroyed. On 3 July 1944, Oberkommando West gave permission to stop construction at both sites, which had been so disrupted by bombing that work could no longer proceed. Three days later an Allied raid succeeded in wrecking the interior of the Watten bunker with a Tallboy bomb that brought down part of the roof. Finally, on 18 July 1944, Hitler decreed that plans for launching missiles from bunkers need no longer be pursued. Dornberger's staff subsequently decided to continue minor construction at Watten "for deception purposes". The site itself was now useless, as the Germans recognised when they wryly codenamed it ''Concrete Lump'', and the liquid oxygen generators and machinery were transferred to the Mittelwerk V-2 factory in central Germany, well away from Allied bombers. The Watten site was captured on 4 September 1944 by Canadian forces. The Germans had evacuated it a few days earlier and removed the pumps which kept the cavernous basement free from water; not long afterwards it began to flood. This made a substantial amount of the bunker inaccessible to the Allies.


Air raids


Subsequent investigations and utilisation

The bunker was inspected on 10 September 1944 by the French atomic scientist
Frédéric Joliot-Curie Jean Frédéric Joliot-Curie (; ; 19 March 1900 – 14 August 1958) was a French chemist and physicist who received the 1935 Nobel Prize in Chemistry with his wife, Irène Joliot-Curie, for their discovery of induced radioactivity. They were t ...
, accompanied by Sandys. Following the visit, Sandys ordered a Technical Inter-Services Mission under Colonel T.R.B. Sanders to investigate the sites at Mimoyecques, Siracourt, Watten, and Wizernes, collectively known to the Allies as the "Heavy Crossbow" sites. Sanders' report was submitted to the War Cabinet on 19 March 1945. Despite the capture of Watten, it was still not known at this time what the site had been intended for. Sanders noted that "the purpose of the structures was never known throughout the period of intensive reconnaissance and attack". Based on the discovery of large aluminium tanks installed in the main part of the bunker, he opined that the Germans had intended to use it as a factory for the production of
hydrogen peroxide Hydrogen peroxide is a chemical compound with the formula . In its pure form, it is a very pale blue liquid that is slightly more viscosity, viscous than Properties of water, water. It is used as an oxidizer, bleaching agent, and antiseptic, usua ...
for use in the fuelling of V-1 and V-2 missiles. He ruled out the possibility that it could have been used for LOX production and concluded, erroneously, that "the site had no offensive role." He recommended that (unlike the Mimoyecques and Wizernes sites) the Watten bunker presented no threat to the UK's security and "there is thus no imperative need, on that account, to ensure the destruction of the workings." The bunker was targeted again by the Allies in February 1945, this time to test the newly developed CP/RA
Disney bomb The Disney bomb, also known as the Disney Swish, officially the 4500 lb Concrete Piercing/Rocket Assisted bomb was a 4,500lb bunker buster bomb developed during the World War II, Second World War by the British Royal Navy to penetrate harde ...
 – a concrete-piercing rocket-assisted bomb designed to double the normal impact velocity, and thereby increase the penetration, of the projectile. The site had been chosen for testing purposes in October 1944 as it had the largest accessible interior area of the targets under consideration and was furthest from an inhabited town. On 3 February 1945, a B-17 of the US Eighth Air Force dropped a
Disney bomb The Disney bomb, also known as the Disney Swish, officially the 4500 lb Concrete Piercing/Rocket Assisted bomb was a 4,500lb bunker buster bomb developed during the World War II, Second World War by the British Royal Navy to penetrate harde ...
on the Watten bunker and scored a hit over the wall section, but the results were inconclusive and the Air Force was not able to determine how well the bomb had penetrated the concrete. Although Disney bombs were used operationally on a number of occasions, the weapon's introduction came too late to be of any significance in the war effort. In January 2009 the body of the Disney bomb was extracted from the roof, where it had embedded itself.


Preservation

The Watten bunker was inspected again on 20 June 1951 by an Anglo-French commission to determine whether it was capable of being reused for military purposes. The British Assistant Military Attaché, Major W.C. Morgan, reported to the Director of Military Intelligence at the
War Office The War Office has referred to several British government organisations throughout history, all relating to the army. It was a department of the British Government responsible for the administration of the British Army between 1857 and 1964, at ...
that the main part of the bunker had not been significantly damaged by bombing and that although it was flooded, if it was patched and drained "the building could be quickly made ready to receive oxygen liquifying plant machinery, or for any other purpose requiring a large and practically bomb-proof building."Morgan, W.C. (30 June 1951) "Crossbow Sites". Memo MA/Paris/732. No further military use was made of the bunker and the land on which it stands reverted to private ownership. It was left abandoned for many years before the owners decided to redevelop the site. In 1973, the bunker was opened to the public for the first time under the name of ''Le Blockhaus d'Éperlecques''. The ownership was taken over by Hubert de Mégille in the mid-1980s and on 3 September 1986 the French state declared it a . The area around the bunker has been re-forested, though it is still heavily scarred by bomb craters, and various items of Second World War military equipment (including a V-1 on a launch ramp) are on display alongside paths around the site. An open-air trail leads to and around the bunker with interpretative signs posted at various points to tell the story of the site and the German V-weapons programme. In 2009, the museum welcomed 45,000 visitors.


See also

* Fortress of Mimoyecques *
La Coupole ''La Coupole'' (), also known as the ''Coupole d'Helfaut-Wizernes'' and originally codenamed ''Bauvorhaben'' 21 ('Building Project 21') or ''Schotterwerk Nordwest'' (Northwest Gravel Works), is a Second World War bunker complex in the Pas-de-Cal ...


Notes


References

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External links


Le Blockhaus d'Éperlecques
– museum website
German bunkers in Northern France3D model of the bunker as it would have looked if completed
(requires Google SketchUp to view) {{DEFAULTSORT:Blockhaus D'eperlecques V-weapon subterranea Museums in Pas-de-Calais World War II museums in France World War II sites in France Military installations established in 1943 Protected areas established in 1986 Ruins in Hauts-de-France World War II strategic bombing lists Operation Crossbow 1986 establishments in France Saint-Omer Monuments historiques of Pas-de-Calais