"On May 16 1943, 19 aircraft set out to destroy three dams in the Ruhr valley - the Mohne, the Eder and the Sorpe - and so damage a vital source of power to the key industrial area of Germany. The mission was hailed a success after the Mohne and Eder were breached. But eight aircraft and 53 crew were lost during the raids."
The men trained at the Derwent dam, where a flypast today paid tribute on the 65th anniversary. The anniversary is the 16th/17th May according to the dates kept in 617 Squadron, the Operational Record Book, 1943-1945. The crews left late on the evening of the 16th.