In February, 1943, the Royal Air Force decided to plan an attack on the five hydroelectric dams on which the Ruhr industrial area depended. Barnes Wallis advised the Royal Air Force to use the new bouncing bomb he had been developing at the National Physics Laboratory in Teddington.
Guy Gibson was selected to take part in Operation Chastise (also known as Dambusters Raid). The targets were the three key dams near the Ruhr area, the Möhne, the Sorpe and the Eder Dam on the Eder River. It was hoped that the raid would result in the loss of hydroelectric power and the supply of water to nearby cities. The success of the operation involved precision bombing. The cylindrical bombs developed by Barnes Wallis had to be dropped from 60 feet to skip into the dam face and roll down it to explode at a depth that triggered a pressure fuse. The pilots had to judge the critical release point by using dual spotlights whose beams converged vertically at 60 feet.
The aircraft used were adapted Avro Lancasters. To reduce weight, much of the armour was removed, as was the mid-upper turret. The substantial bomb and its unusual shape meant that the bomb doors were removed and the bomb itself hung, in part, below the body of the aircraft. The crews practised over the Eyebrook Reservoir, the Derwent Reservoir and the Fleet Lagoon at Chesil Beach. The final test flights took place on 29th April 1943.
Operation Chastise began on the night of 15-16th May. The first wave of aircraft, led by Guy Gibson, would first attack the Möhne Dam. The second group was to attack the Sorpe Dam whereas the third group was a mobile reserve and would take off two hours later, either attacking the main dams or bombing smaller dams at Schwelm, Ennepe and Diemel.
Two aircraft piloted by Les Munro and Geoff Rice were forced to return to base following technical problems. Robert Barlow and Vernon Byers were shot down and crashed into the Waddenzee, whereas Bill Astell came down somewhere over Roosendaal.
The first group of aircraft piloted by Guy Gibson, Melvin Young, John Hopgood, Mick Martin, David Shannon, Henry Maudslay, David Maltby and Les Knight arrived safely at their first target. Gibson bombed first but it failed to hit the Möhne Dam. During his run Hopgood aircraft was hit by flak and destroyed. Gibson now flew his aircraft across the dam to draw flak from Martin's run. Martin's aircraft was hit but he made a successful attack.
Melvin Young was the next man to go. Guy Gibson recorded that Young's bomb made "three good bounces and made contact (with the dam)." A huge column of water rose and a shock wave could be seen rippling through the lake. The dam was now beginning to break but it did not collapse immediately. David Maltby was now ordered to attack the dam. He later said that "the crown of the wall was already crumbling" and that he could see a "breach in the centre of the dam" before dropping his bomb. Gibson radioed back to headquarters that he could now see a great gap, some 150 metres long, in the dam and a torrent of water that looked "like stirred porridge in the moonlight."
Guy Gibson then led Melvin Young, David Shannon, Henry Maudslay and Les Knight to the Eder Dam. The topography of the surrounding hills made the approach difficult and the first aircraft, Shannon's, made several unsuccessful runs without dropping his bomb. Shannon later recalled: "The Eder was a bugger of a job. I was the first to go; I tried three times to get a spot on approach but was never satisfied. To get out of the valley after crossing the dam wall we had to put on full throttle and do a steep climbing turn to avoid a vast rock face. My exit with a 9000lb bomb revolting at 500rpm was bloody hairy."
Gibson ordered David Shannon to take a break and called up Henry Maudslay to have a go. After Maudslay had two unsuccessful runs, Shannon made another attempt and this time he released his bomb and it hit the target. Maudslay made another run but his bomb hit the top of the dam and the aircraft was caught in the blast.
Only Les Knight had a bomb left. His first run ended in failure but the next one resulted in the bomb hitting the dam. Guy Gibson later recalled: "We saw the tremendous earthquake which shook the base of the dam, and then, as if a gigantic hand had punched a hole through cardboard, the whole thing collapsed."
Joe McCarthy reached the Sorpe alone. It was the most difficult to breach as it was a vast earth dam rather than the concrete structures of the Mohne and Eder dams. McCarthy's aircraft successfully dropped its bomb but it did little damage. Three of the reserve aircraft were directed to the Sorpe. However, they were unable to breach the dam.
Meanwhile, Guy Gibson, Melvin Young, David Shannon, and Les Knight were involved in a dangerous journey to get back to England. Henry Maudslay had started off earlier after his aircraft had been badly damaged while bombing the Eder Dam. However, he was shot down close to the German-Dutch border. At 02.58 gunners at Castricum-aan-Zee managed to hit Young's aircraft. It crashed into the sea and all its crew were killed.
Only 11 of Gibson's 19 bombers survived the mission. Eight aircraft had been lost and 53 flyers had been killed in the operation. Another three were captured and ended the war in prison camps.
Guy Gibson was awarded the Victoria Cross for his role in the mission. However, to use the bouncing bomb, the pilots had to fly very low and 45 per cent of the planes used in the Dambusters Raid were brought down by German anti-aircraft guns. The RAF could not sustain such high losses and the bouncing bomb was rarely used again during the war.