Operation Chastise


The Möhne dam the day following the attacks

Date: 16–17 May 1943
Location: Eder, Möhne, and Sorpe (Röhr) rivers, Germany
Result: 2 dams breached

Casualties and losses
British: 8 aircraft lost, 53 aircrew killed, 3 aircrew taken prisoner.
German: 2 dams breached, 1 dam lightly damaged, c. 1,600 civilians killed, (including c, 1,000 prisoners and slave labourers, mainly Soviet)

Operation Chastise, commonly known as the Dambusters Raid, was an attack on German dams carried out on the night of 16/17 May 1943 by 617 Squadron RAF Bomber Command, later called the Dam Busters, using special "bouncing bombs" developed by Barnes Wallis. The Möhne and Edersee dams were breached, causing catastrophic flooding of the Ruhr valley and of villages in the Eder valley; the Sorpe Dam sustained only minor damage. Two hydroelectric power stations were destroyed and several more damaged. Factories and mines were also damaged and destroyed. An estimated 1,600 civilians – about 600 Germans and 1,000 enslaved labourers, mainly Soviet – were killed by the flooding. Despite rapid repairs by the Germans, production did not return to normal until September. The RAF lost 56 aircrew, with 53 dead and 3 captured, amid losses of 8 aircraft.

Concept

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Assignment


Air Vice-Marshal Ralph Cochrane, Wing Commander Guy Gibson, King George VI and Group Captain John Whitworth discussing the Dambuster Raid in May 1943

The operation was given to No. 5 Group RAF, which formed a new squadron to undertake the dams mission. It was initially called Squadron X, as the speed of its formation outstripped the RAF process for naming squadrons. Led by 24-year-old Wing Commander Guy Gibson, a veteran of more than 170 bombing and night-fighter missions, twenty-one bomber crews were selected from 5 Group squadrons. The crews included RAF personnel of several nationalities, members of the Royal Australian Air Force (RAAF), Royal Canadian Air Force (RCAF) and Royal New Zealand Air Force (RNZAF). The squadron was based at RAF Scampton, about 5 mi (8 km) north of Lincoln.

The targets selected were the Möhne Dam and the Sorpe Dam, upstream from the Ruhr industrial area, with the Eder Dam on the Eder River, which feeds into the Weser, as a secondary target. The loss of hydroelectric power was important but the loss of water to industry, cities and canals would have greater effect and there was potential for devastating flooding if the dams broke.

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Preparations


Barnes Wallis and others watch a practice Upkeep bomb strike the shoreline at Reculver, Kent.

Bombing from an altitude of 60 ft (18 m), at an air speed of 240 mph (390 km/h) and at set distance from the target called for expert crews. Intensive night-time and low-altitude training began. There were also technical problems to solve, the first one being to determine when the aircraft was at optimum distance from its target. The Möhne and Eder Dams had towers at each end. A special targeting device with two prongs, making the same angle as the two towers at the correct distance from the dam, showed when to release the bomb. (The BBC documentary Dambusters Declassified (2010) stated that the pronged device was not used, owing to problems related to vibration and that other methods were employed, including a length of string tied in a loop and pulled back centrally to a fixed point in the manner of a catapult.)

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Bomb damage assessment

Bomber Command wanted a bomb damage assessment as soon as possible and the CO of 542 Squadron was informed of the estimated time of the attacks. A photo-reconnaissance Spitfire, piloted by Flying Officer Frank 'Jerry' Fray, took off from RAF Benson at 07:30 hours and arrived over the Ruhr River some hours after first light.[28] Photos were taken of the breached dams and the huge floods.[29] The pilot later described the experience:

When I was about 150 miles [240 km] from the Möhne Dam, I could see the industrial haze over the Ruhr area and what appeared to be a cloud to the east. On flying closer, I saw that what had seemed to be cloud was the sun shining on the floodwaters. I looked down into the deep valley which had seemed so peaceful three days before but now it was a wide torrent. The whole valley of the river was inundated with only patches of high ground and the tops of trees and church steeples showing above the flood. I was overcome by the immensity of it.

— Jerry Fray

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In popular culture

• In 1954 a radio dramatisation of Paul Brickhill's book The Dam Busters was produced by Australasian Radio in 26 half-hour episodes.
• A 1955 film, The Dam Busters, was made about the raids and was very popular.

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