Wallis realized that a much smaller explosive charge would suffice if it exploded against the dam wall under the water but German reservoir dams were protected by heavy torpedo nets to prevent an explosive device from travelling through the water. No bomber aircraft was capable of flying at such an altitude or of carrying such a heavy bomb and although Wallis proposed the six-engined Victory Bomber for this purpose this was rejected. At first, Wallis wanted to drop a 10 long tons (22,000 lb 10,000 kg) bomb from an altitude of about 40,000 ft (12,000 m), part of the earthquake bomb concept. Wallis had worked on the Vickers Wellesley and Vickers Wellington bombers and while working on the Vickers Windsor, he had also begun work, with Admiralty support, on an anti-shipping bomb, although dam destruction was soon considered. The mission grew out of a concept for a bomb designed by Barnes Wallis, assistant chief designer at Vickers. A one-off surprise attack might succeed but the RAF lacked a weapon suitable for the task. Calculations indicated that attacks with large bombs could be effective but required a degree of accuracy which RAF Bomber Command had been unable to attain when attacking a well-defended target. The dams provided hydroelectric power and pure water for steel-making, drinking water and water for the canal transport system. The RAF lost 56 aircrew, with 53 dead and 3 captured, amid losses of 8 aircraft.īefore the Second World War, the British Air Ministry had identified the industrialised Ruhr Valley, especially its dams, as important strategic targets.

Despite rapid repairs by the Germans, production did not return to normal until September. An estimated 1,600 civilians – about 600 Germans and 1,000 enslaved labourers, mainly Soviet – were killed by the flooding.

Factories and mines were also damaged and destroyed. Two hydroelectric power stations were destroyed and several more damaged. 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.

Operation Chastise, commonly known as the Dambusters Raid, was an attack on German dams carried out on the night of 16/ by 617 Squadron RAF Bomber Command, later called the Dam Busters, using special ' bouncing bombs' developed by Barnes Wallis.

1,000 prisoners and slave labourers, mainly Soviet) Eder, Möhne and Sorpe (Röhr) rivers, Germany

For apple instal WWII: Clear Sky 41