AJ-G THE DAMBUSTERS  (617 Squadron)

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The Briefing

In only 8 weeks, Chastise was ready to go. Wallis, Chadwick and everyone involved had managed to perfect Upkeep, modify the Lancasters (including designing a release mechanism), form and prepare an entire squadron and iron out all of the major problems facing them. Their effort was already a great achievement.

With only two days to go before Chastise was due to be launched, the Chiefs of staff had not confirmed the targets. More worryingly, they had not even made up their minds whether to launch the attack at all. The Navy had great hopes that a variation on Upkeep called Highball that could be used to sink enemy shipping and U-boats and thought that the dams raid would compromise the secrecy of Highball. They did however decide to go for the dams because Highball was still having teething problems and if they waited for the problems to be solved they would have missed the window in which the lakes were full.

The day before the attack on May 15th, Gibson was given a full briefing on the attack and the targets. Until then he and his squadron had still been kept in the dark. The three main objectives were:

  • Target A: The Mohne Dam
  • Target B: The Eder Dam
  • Target C: The Sorpe Dam

The secondary targets were:

  • Target D: The Lister Dam
  • Target E: The Ennepe Dam
  • Target F: The Diemel Dam

Gibson informed his two flight commanders Young and Maudslay, his deputy leader Hopgood and Bob Hay, Martins' bomb aimer who was squadron bombing leader.

After the meeting, Gibson was informed that his black Labrador, Nigger, had been hit by a car and killed outside Scampton's main gate. Nigger had flown with Gibson on many occasions and had become one of the 'boys' to crews, often enjoying a pint with them. Gibson did not want the others to know in case they thought it was a bad omen. He spent the night in a mood of depression. The next day (May 16th 1943) he arranged for the dog to be buried at around midnight, just about the same time he was due to lead the first wave into attack the Mohne dam.

On 16th May 1943 at 1800 hours (6pm), all crew members assembled for the final briefing. It was presented by Gibson, Wallis and Cochrane.
Gibson outlined the general plan of attack before the crews were briefed in detail about routes, call signs, codewords, weather conditions and ammunition loads. (For many of the crews this was the first time Gibson had spoken to them).
Wallis then explained the basic principles and development of the weapon and what he expected it to do. He outlined the characteristics of the dams and explained the effect on Hitler's industry if they were breached.
Finally Cochrane closed the briefing wishing the crews good luck.



The attacks would be carried out in three waves. The first wave of nine aircraft (AJ-G, AJ-M, AJ-P, AJ-A, AJ-J, AJ-Z, AJ-L, AJ-B and AJ-N) would take off in three sections ten minutes apart. They would fly a southerly route crossing the enemy cost at the Scheldt estuary in Holland. Their first target would be the Mohne dam. Wallis believed that only one Upkeep would be required to cause a breach in the dam. The planners allowed Gibson to use three, firstly in case one was not enough and secondly to expand the gap. Once the Mohne had been breached, the aircraft that had attacked and no longer had an Upkeep would turn back home while the remaining aircraft with Upkeeps would go onto Target B - the Eder. After breaching the Eder the process would be repeated and aircraft with remaining Upkeeps would proceed to Target C - the Sorpe.

The Sorpe would be the primary target of the second wave consisting of five aircraft (AJ-T, AJ-E, AJ-W, AJ-K and AJ-H). The second wave would actually leave Scampton first in order to fly a more northerly route to the Dutch island of Vlieland then down the Zuider Zee and join the flight path of the first wave just over the German border. The two routes were chosen to suggest to enemy radar that these were minor attacks. After attacking the Sorpe, the second wave would use any remaining bombs to attack the secondary targets - the Ennepe, Lister and Diemel.

The third wave of five aircraft (AJ-C, AJ-S, AJ-F, AJ-O and AJ-Y) would leave Scampton more than two hours after the first two waves. They would follow the route of the first wave and act as mobile reserve to attack any of the primary targets that had not been breached or move onto the secondary targets. If all targets had been breached before they reached the Dutch coast, the reserve unit would be recalled.

All crews were warned not to stray from the planned routes because they were designed to avoid flak batteries, night fighter bases and hot-spots all the way from the Dutch coast to the dams and back. They would maintain low level during the whole flight there and back. They were also warned that under no circumstances should anyone return with an Upkeep intact. It was far too dangerous to attempt to land with an armed weapon. They were advised to release the bomb over preferably German land.

After the briefing, the crews sat down to the traditional eggs and bacon before leaving to make their final preparations for the attack. Some wrote letters to their loved ones in case they did not make it back. Some made final meticulous inspections of their aircraft and weapon and one or two tried to make a last minute phone call only to find that there was a security cover on all communications of any kind outside of the base.

Everything had been prepared and the crews were ready to make history…

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