Wing Commander Guy Gibson was just completing his 173rd trip over Germany; he was 25 years of age and already had a D.S.O. and D.F.C. He was expecting to go to Cornwall on leave when he received a summons to report to 5 Group Headquarters. The commander of 5 Group was Air Vice-Marshal the hon. Ralph Cochrane, chosen by “Bomber” Harris to form the new squadron with Guy Gibson as its Wing Commander. Gibson was told he had four days to form a new squadron based at Scampton and he would not be told the target but was to concentrate on low level flying.
Gibson met Wallis a few days later and Wallis was horrified to learn he had not been told what target he was training for. Security was extremely tight for everyone involved in Project Downwood, from the inventor to the flight crews involved. It was only later Gibson learned of the 3 dams and was secretly relieved it was not going to be the “Tirpitz” that was causing the deaths of many of his friends. All mail was censored and telephones tapped to ensure nothing was given away about the operation that was now only 10 weeks away.
Wing Commander Dann, a sighting specialist, contacted Gibson with an answer to the problems he was having with accurate bombing. There were 2 towers on each dam about 600 feet apart. Using the simple gadget they were able to drop their bombs with an average error of only four yards letting the bomb make 3 skips before hitting the dam wall.
Using two searchlights beneath the Lancaster, the arcs of the lights touched on the surface of the water when the plane was at the agreed height for dropping, in this case 150 feet which was later reduced to 60 feet.
On the morning of May 15 pilots, navigators and bomb aimers were summoned to the briefing room. Gibson introduced Barnes Wallis and Mutt Summer and showed them the 3 models of the Mohne, Eder and Sorpe dams. Wallis told them of the effects that a successful operation would have on German industry. They spent 2 hours learning all they could about the targets, discussing drawbacks and making suggestions on approach, etc. They then went back to their mess rooms for an early night as the raid was taking place the next evening.
The Night of the Raid
At 4.00pm all crews were summoned to the briefing room. Soon all 133 bomber personnel were seated and heard for the first time their intended targets. Gibson told them what he had told the others the previous day, Wallis told them about the dams and what their destruction could do and Cochrane finished with a short crisp talk.
Formation 1 consisting of three waves, taking off with ten minutes between waves:
They were to attack the Moehne and once it was breached those who had not yet bombed would go on to the Eder.
Formation 2: one wave in loose formation:
These would attack the Sorpe, crossing the coast by the northern route as a diversion to split the German defences.
Formation 3: would take off later as the mobile reserve:
There followed a lengthy period of waiting, always the worst time before taking off. Gibson spoke to Chiefy Powell asking him to bury his dog, Nigger, at midnight. Nigger had been hit by a hit and run driver the previous day and it was an unusual request from the usual taciturn Gibson but he had it in his mind that he and Nigger might be going into the ground about the same time that evening.
At exactly ten past nine a red Very light curled up from Gibson’s aircraft, the signal for McCarthy’s five aircraft to start. The northern route was longer and they were taking off ten minutes earlier.
The map below shows the optimum routes they were to follow.
The dam did not give way and once the water had settled Gibson told Hopgood to take his turn. M for Mother was hit by flak as it came in for its run, the bomb bounced over the dam onto the power house below and M for Mother spun into the ground before anyone could get out.
P for Popsie was next and Gibson told them he would try and distract the flak by flying across the dam as he made his run in. He dropped his bomb and made it through the flak. When the bomb exploded water was pushed over the top of the dam but it did not give way.
A for Apple was next and this time both Gibson and Martin tried to distract the flak. Digby Young dropped his bomb as accurately as the others but only a high plume of water was seen.
This time he called Maltby in and then continued their distracting run across the dam. Maltby dropped his bomb and as he pulled away Gibson called up Shannon to start his run. When he heard Martin say, “It’s gone.” Gibson turned back over the dam and saw a ragged hole 100 yards across and 100 feet deep had appeared in the dam's face.
At the Eder Maudslay went first and had tremendous difficulty because of the hilly terrain to get low enough to release his bomb. After several attempts he finally released it only to see it bounce over the parapet. He never returned from the raid. Shannon was called up next and after a couple of goes finally released his bomb perfectly and managed to get back into the air. But the dam still stood. There was only Knight left and after aborting his first attempt came back-round and placed his bomb exactly right. As the water erupted Gibson turned his aircraft for a look and watched as the face of the dam collapsed and a torrent rush down the valley. The code word “Dinghy” was sent back to base to tell them the Eder had been destroyed and Gibson and the remaining Lancasters turned back to England.
McCarthy was the only Lancaster to get through to the Sorpe. After two abortive runs due to the hilly terrain he was finally able to drop his bomb accurately. He watched 50 yards of the parapet come crashing down and sent his successful code word back to London.
Only 10 planes returned from the raid. 56 young men out of the original 133 were missing. 3 of one craft had parachuted out at a very low height and spent the rest of the war in a prison camp.
Wallis was distraught when he realised how costly the raid had been, “If only I had known, I’d never have started this.”
Later Gibson was awarded the Victoria Cross, Martin, McCarthy, Maltby, Shannon and Knight got D.S.O.’s, Bob Hay, Hutchinson, Leggo and Walker got bars to their D.F.C’s. There were ten D.F.C.’s awarded and twelve D.F.M.’s.
When the King and Queen visited the new squadron they were able to select from a competition Gibson had run on a design for a squadron badge. Unanimously they picked a drawing showing a dam breached in the middle with water flowing out and bolts of lightning above with the motto “Apres nous le deluge”.