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'Éperlecques' (''Dutch: Sperleke'') is a small village and commune of the Pas-de-Calais ''département'', in northern France, north of Saint-Omer.

Contents

Blockhouse

Planning

Mission change and capture

References & Footnotes

Blockhouse

''Le Blockhaus'', in the nearby woods, is a vast concrete structure built by the German army during the Second World War for the V-2 rocket. The site was given the code name Kraftwerk Nord West (KNW).
It is the largest blockhouse in northern France and was originally intended as a factory and launch facility for the V2. This function was transferred to the nearby site of La Coupole before KNW was completed and the blockhouse was instead used in producing the liquid oxygen necessary for the rockets' fuel.

Planning

In December 1942, Albert Speer ordered Peenemünde officers and engineers (including Dr Ernst Steinhoff and Dornberger's Chief of Staff, Lieutenant-Colonel Thom) to tour the Artois region in Northeast France and locate a Channel coast site for a V-2 launch facility West of 'Watten', V2--Der Schuss ins Weltall, , Walter, Dornberger, Bechtle Verlag, 1952 -- US translation ''V-2'' Viking Press:New York, 1954, in the forest of Eperlecques, near St Omer and Calais. The Birth of the Missile:The Secrets of Peenemünde, , Ernst, Klee, Gerhard Stalling Verlag, 1963, English translation 1965, The construction used 120,000 cubic metres of concrete and slave labour working for the Organisation Todt. A complex system of railway lines brought the workers and concrete on site from Calais and St Omer. The blockhouse was designed to be able to launch 36 rockets per day and also make sufficient liquid oxygen to fuel them, a daily requirement of 65 tonnes of it. By combining the fuelling and launching at the same heavily fortified site, the Nazis were able to avoid the evaporation losses of transporting the liquid oxygen.
Four 4-storey high Heyland compressors were intended to be installed to make the liquid oxygen and the rockets were to be assembled in the northern part of the site and moved on trollies to be launched in the southern part.
On July 8, 1943, Hitler viewed a colour V-2 rocket film and scale models of the Watten 'bunker' and mobile launching-troop vehicles. Instead of the "shoot-and-run" mobile launching Walter Dornberger advocated, Hitler ordered that there should be more than one fixed bunker.
Bombing damage of the north of the structure on August 27, 1943 resulted in a change in construction technique. The south section of the blockhaus was constructed by initially constructing a 5 meter (~16 feet) thick concrete plane weighing 37,000 tons, which was to serve as the roof. After the plane was constructed, hydraulic jacks were used to lift the roof several meters, at which point concrete was poured to create a surrounding wall and 4 interior supporting walls. After this pour had sufficiently hardened, the roof was further raised several meters and another pour was performed; this was repeated until completion. The final structure built using this method was 28 m (~92 feet) high. This technique permitted construction to continue in spite of repeated allied bombings using munitions of up to 6 tonne, including the famous tallboy bombs.
By September 1943, construction at Watten (as well as at Wizernes, and the 'special' V-2 site at Sottevast) was on schedule, despite Allied bombings. Hitler’s Rocket Sites, , , Heashall, St Martin's Press, 1985,

Mission change and capture

Eventually the Nazi command considered the site too vulnerable and instructed the engineers at the blockhouse to concentrate on liquid oxygen production for their new underground launch site at La Coupole, using three Heyland compressors. The Kraftwerk Nord West (KNW) code name was changed to KNW ALT (KNW Old) to reflect this.
On July 3, 1944, the ''Oberkommando West'' gave permission to stop construction at the heavily damaged Watten and Wizernes sites. The Rocket Team, , Frederick I, III, Ordway, Thomas Y. Crowell, , Finally, on July 18, 1944, Hitler ruled that the V-2 'bunker' launch plans need no longer be pursued. The Mare's Nest, , David, Irving, William Kimber and Co, 1964, Nevertheless, a few days after July 18, 1944, Dornberger's staff decided to continue minor construction at Watten (wryly code named 'Concrete Lump') ''for deception purposes'', and the valuable liquid-oxygen generators and machinery were transferred to the Mittelwerk. Some historians believe the engineers at the blockhouse still worked on this part of the site as a standby option, with or without official permission.
On September 4, 1944, Canadian forces captured the Watten site, the most easterly of the fixed V-2 rocket launch sites. ''Le Blockhaus'' is protected under French law as a historic building and is open to the public.

Operation Crossbow bombing of 'Éperlecques (Watten)'
Mission	Date	Result
	August 27, 1943	Thought to be for the V-1 flying bombs, and unknown to the Allies at the time of the attack to be designed for V-2 rockets, Flying Bomb, , Peter G, Cooksley, Charles Scribner’s Sons, 1979, Flying Fortresses of the US Eighth Air Force, briefed on an 'aeronautical facilities' mission, low-level bomb the freshly-poured concrete beginning to harden at the 'special target'/'large site' The Battle of the V-Weapons, 1944-1945, , Basil, Collier, The Emfield Press, 1976, at 'Watten'. Hitler's Last Weapons: The Underground War against the V1 and V2, , Józef, Garliński, Times Books, 1978, The Rocket and the Reich: Peenemünde and the Coming of the Ballistic Missile Era, , Michael J, Neufeld, The Free Press, 1995, Bombing caused the still-wet cement to solidify into a mess that was beyond description. Peenemünde to Canaveral, , Dieter K, Huzel, Prentice Hall, 1960,
Mission 38	August 30, 1943	36 B-26's are dispatched to an ammunition dump at 'Foret d'Eperlecques' near Saint-Omer, France; 33 hit the target at 1859 hours; 14 aircraft are damaged; casualties are 3 WIA. 8th Air Force 1944 Chronicles '1943':July, August, September '1944':February, June, July, August
Mission 92	September 7, 1943	US Eighth Air Force conducted a light attack on the 'Watten' site.
Mission 205	February 2, 1944	95 of 110 B-24s hit V-weapon construction sites at St Pol/Siracourt and 'Watten', France; 2 B-24s are lost, 1 is damaged beyond repair and 2 damaged; casualties are 10 KIA and 19 MIA. 183 P-47s escort the B-24s without loss.
Mission 214	February 8, 1944	53 of 54 B-24s hit the V-weapon site at Siracourt, France while 57 of 73 B-24s hit the V-weapon site at 'Watten', France; 41 B-24s are damaged and 10 airmen are WIA; escort is 89 Eighth and Ninth Air Force P-47s
	June 19 & July 27, 1944	The nearest Tallboy bomb dropped by Royal Air Force No. 617 Squadron on June 19 landed 50 yards (46 m) from the target, Campaign Diary '1944':June, July while one Tallboy hit the target on July 27 (but did not penetrate the structure.) World War II German hardened A4/V2 rocket launch sites The Tallboy bombs dug up the nearby ground and tilted the machinery foundations, making the bunker useless.
Mission 515 Aphrodite	August 4, 1944	The first APHRODITE mission is flown using 4 radio-controlled war weary B-17s as flying bombs; targets are Mimoyecques, Siracourt, 'Watten', and Wizernes V-weapon sites but none are hit; 1 drone B-17 crashes killing 1 crew. Escort is provided by 16 P-47s and 16 P-51s.
Aphrodite	August 6, 1944	crews were able to abandon the BQ7 drones without complications, a few minutes later one lost control and fell into the sea. The other also lost control, but turned inland and began to circle the important industrial town Ipswich. After several minutes, it crashed harmlessly at sea. Aircraft: 1942 USAAF Serial Numbers (42-30032 to 42-39757) B-17 30342 ★ Taint A Bird ★ : impacted at Gravelines, probably due to flak damage. B-17 31394: experienced control problems and crashed into sea. B-17 30212 ★ Quarterback ★ : experienced control problems and crashed into sea

References & Footnotes