In World War II the Ruhr Valley and its dams had been identified as one of Germany's main industrial areas including factorys and hydro-electric power generation. The area was to be designated as a prime target but there was much deliberation on how to attack the area -- repeated bombing with large bombs could break the dams but a precision attack was required.
Barnes Wallis an aircraft designer who designed the wellington heavy bomber, came up with a dam breaking design and the final design for a bouncing bomb.
The initial idea was to drop a large bomb from high altitude but none of the bomber aircraft were capable of flying at high altitude with a heavy bomb payload at the time. The dams were protected by torpedo nets to stop attacks by torpedo carrying aircraft where the impact could be guaranteed below the water line against the dam wall.
A barrel bomb spinning at around 500 rpm, dropped at a sufficiently low height at the right speed could bounce over the surface of the water, just like skimming a stone in a series of bounces before reaching the dam wall. It could then roll down the side of the dam to its pre-determined depth before exploding against the dam wall.The calculations had to be critical otherwise the bomb or wake could bounce back up and take out the aircraft or the bomb would not bounce or move in a straight line to meet the target.
The targets selected were the Möhne Dam and the Sorpe Dam, with the Eder Dam as a secondary target. Bombing would take place from a height of 50 to 60ft, at around 200 mph and the bomb dropped a set distance from the dam wall. It was expected that the raids would take place at night-time and at low-altitude so extensive flying and bombing training was begun. It would be up to 617 Squadron flying modified Avro Lancaster bombers to carry out the raids.
The direct hits on the Möhne dam broke a few holes the largest around 240 feet wide and 260 feet deep. The broken dam let go of around 300 million tons of water into the Ruhr valley. A wave swept through the valleys causing significant flooding and damage to factories, houses, roads and rail links.
Last update: 17/06/2011 gdr-games.com ©2010