12 Wellingtons and 4 Lancasters minelaying off Biscay ports but the Wellingtons were recalled. No aircraft lost.
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from selected crews in 5 Group and the squadron trained for 6 weeks for this special operation. 19 Lancasters were dispatched in 3 waves, each aircraft armed with the special 'bouncing bomb' developed by Barnes Wallis for attacking German dams. The entire operation was to be carried out at low level to escape attack from German night fighters and to release the bombs just above the water in the dams.
One aircraft had to return early after it struck the sea a glancing blow which tore off its bomb. 5 further aircraft were shot down or crashed before reaching their targets and 1 was so badly damaged by Flak that it had to turn back. This left 12 Lancasters available to bomb the dams. Wing Commander Gibson's aircraft and 4 other crews bombed the Mhne Dam and breached it despite intense fire from light Flak defending the dam. 3 aircraft went on to bomb the Eder Dam, which was also breached. 2 aircraft bombed the Sorpe Dam and 1 the Schwelme Dam but without causing breaches in their walls. The twelfth surviving aircraft could not find its target in misty conditions and returned to England without dropping its bomb. 3 further Lancasters were shot down after they had bombed.
Total casualties were 8 aircraft out of the 19 dispatched. It is estimated that 4 were shot down by light Flak, 1 crashed after being damaged by the explosion of its own bomb, 2 crashed after hitting electricity cables and 1 after striking a tree when its pilot was dazzled by a searchlight. Of the 56 crew members in these planes, 53 were killed and only 3 became prisoners of war, 2 of them being badly injured. For his leadership of this amazing operation and for his courage in attacking Flak positions at the Mhne Dam after having carried out his own bombing run, Wing Commander Gibson was awarded the Victoria Cross. 34 other men received decorations.
The breaching of the Mhne and Eder Dams were major achievements. The Mhne reservoir contained nearly 140 million tons of water and was the major source of supply for the industrial Ruhr 20 miles away. The water released caused widespread flooding and disruption of rail, road and canal communications and of the supply of electricity and water. The water-supply network was particularly affected by the silting up of pumping stations by the flood water. It is not possible to state the effect of all this upon industrial production in precise terms but there was certainly some disruption and water rationing was in force until the winter rains came and filled the reservoirs again.
19 (a and b). The breach in the Mhne Dam caused by 617 Squadron. The conical shapes on the wall are dummy fir trees; the flotation balls visible on the far side of the lower water are the remains of the anti-torpedo netting which had been inside the dam before the raid.
The flood of water beating against a rail bridge.
The Eder was even larger than the Mhne, containing 210 million tons of water, but it was 60 miles from the Ruhr. The city of Kassel, 25 miles away, and the inland waterway system in the Kassel area, were more affected by the attack on the Eder than was the Ruhr area. The German view is that, if the aircraft which were allocated to the Eder had been switched to the Sorpe Dam, the effect upon the Ruhr's industrial production would have been extremely serious, but the Sorpe's construction was of a nature which made it a difficult target for the Wallis bomb, hence its low priority in the raid. The Sorpe reservoir just managed to keep the Ruhr supplied with water until the Mhne Dam was repaired.
The number of people drowned has been calculated at 1,294, most of them near the Mhne Dam. The town of Neheim-Hsten, which was situated 5 miles downstream of the Mhne Dam, took the full impact of the flood and at least 859 people died there. By one of those tragedies which periodically struck foreign workers and prisoners of war whose camps were near targets in Germany, 493 foreigners - mostly Ukrainian women landworkers - died in their camp at Neheim-Hsten. It is believed that 58 or more of the dead were around the Eder Dam. The total number of dead - as quoted at 1,294 - was a new record for a raid on Germany, easily exceeding the 693 people killed at Dortmund in a raid earlier in May in which 596 aircraft took part!
Minor Operations: 9 Mosquitoes to Berlin, Cologne, DÜSSELDORF and Mnster, 54 aircraft minelaying off Biscay ports and in the Frisians, 4 O.T.U. sorties. 1 Wellington minelayer lost.
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as a special squadron in 5 Group specifically for the raid on the German dams which took place on
