This Date in History: May 16/17th.1943.
Operation Chastise

Operation Chastise was an attack on German dams carried out on 16-17 May 1943
by Royal Air Force No. 617 Squadron, subsequently known as the "Dambusters",
using a specially developed "bouncing bomb" invented and developed by Barnes Wallis.
The Möhne and Edersee Dams were breached, causing catastrophic flooding of the Ruhr valley
and of villages in the Eder valley, while the Sorpe dam sustained only minor damage.

Prior to World War II, the British Air Ministry had identified Germany's heavily industrialised Ruhr Valley,
and especially its dams, as important strategic targets: in addition to providing hydro-electric power
and pure water for steel-making, they also supplied drinking water and water for the canal transport system.
The methods used to attack the dams had been carefully worked out. Calculations indicated that repeated air strikes
with large bombs could be effective, but required a degree of accuracy which Bomber Command
had been unable to attain in the face of enemy defences.

The mission grew out of a concept for a bomb designed by Barnes Wallis and developed by his team at Vickers.
Wallis was Assistant Chief Designer at Vickers. He had worked on both the Vickers Wellesley
and Vickers Wellington bombers. While working on the Vickers Windsor he had also begun work,
with support of the Admiralty, on a bomb designed initially for attacking ships,
though dam-destruction was soon considered.

Wallis's breakthrough design was a drum-shaped bomb spinning backwards at over 500 rpm,
dropped at a sufficiently low altitude, at the correct speed, would skip for a significant distance
over the surface of the water in a series of bounces before reaching the dam wall.
Its residual spin would run the bomb down the side of the dam to its underwater base.
Using a hydrostatic fuse, an accurate drop could bypass the dam's defences
and enable the bomb to explode against the dam.




On the night of 16-17 May 1943, 617 Squadron Lancasters, led by Wing Commander Guy Gibson,
flown at low level crossed the English Channel towards the enemy coast.
Their targets were the Mohne, Sorpe and Eder dams in the heart of the Ruhr.
The attacking Squadron was arranged in three waves of aircraft.
The first wave comprised three groups of three aircraft at 10 minute intervals apart
headed for the Mohne and Eder Dams. The second wave of five Lancasters headed direct
to the Sorpe whilst the third wave of five Lancasters, would act as backup.




Wing Commander Guy Gibson's Lancaster, with all it's lights on, attempted to draw the dam's defensive fire
away from Flt. Lt. Maltby's attacking aircraft, as it passes between the towers of the Mohne Dam,
just as his mine explodes and breaches the dam.




After the attack, Wing Commander Guy Gibson, under fire from the defending garrison,
powered his Lancaster 'AJ-G' at full throttle over the Möhne dam to confirm the extent
of the successful breach. Below him, and clearly visible, the bright moonlight revealed
the huge rupture in the dam’s massive wall as the swirling avalanche of water surged
into the valley below. With the subsequent destruction of the Eder Dam, and the damage to the Sorpe Dam,
the men of 617 Squadron had achieved what they trained and planned for.

With the attacks completed, eight of the attacking Lancasters failed to return
from the raids with a cost of 53 crew members.




At the completion of the 3 raids on the night of May 16/17,
2 dams were breached while the third was only damaged.
So successful was the British raid that the Germans
installed mumerous cabled gas bags to protect
the Ruhr Dams from future attacks....


More details about the raid found here:
http://en.wikipedia.org/wiki/Operation_Chastise


Cheers mates
David