As Great Britain urgently sought to counter Germany’s industrial might in the Second
World War, some military planners came to believe that striking the Third Reich’s
energy supply might be able to halt the German war machine. While the idea did not pan out
exactly how the British hoped, it did lead to one of the most famous bombing raids of
the war. During Operation Chastise, Britain’s Squadron 617 launched a daring and innovative
attack on German hydroelectric dams. The mission would see the use of a new, specially designed
bomb... one that could skip on the water like a pebble before blowing up its target at precisely
the right point...
Bouncing Bombs
The British Air Ministry knew that the Ruhr Valley and its dams were of crucial importance
to Germany’s stability even before the Second World War started. In particular, the Möhne
dam held the drinking water supply for the villages in the area. Together the Möhne
Dam and the Sorpe dams provided electricity for the region. The dams also supplied water
for the canals and for steel processing. Destroying the two dams, and others in the area would
theoretically allow the British to disrupt German lives and halt their war machine.
According to calculations made by the Royal Air Force, destroying them would require large
bombs delivered with greater accuracy than the technology at their disposal. Therefore,
no plans had been made to attack the Ruhr Valley.
Operation Chastise was born backward, planned as a result of technology developments by
the assistant chief designer at Vickers, Barnes Wallis. He first designed a 10-tonne concept
earthquake bomb that he wanted aircraft to drop from 40,000 feet above the ground. Since
no British planes could fly that high with such a heavy payload, he began looking into
other possibilities. The main challenge faced by Wallis was that German dams were protected
by torpedo nets.
His alternative was a 9,000-pound cylindrical bomb similar to a depth charge. These weapons
had a hydrostatic fuse, meaning they would detonate underwater at a predetermined depth.
Most importantly, the bomb’s key feature was inspired by him bouncing pebbles across
a water tub. The bouncing bomb would be released with a backward spin of 500 revolutions per
minute. It would skip across the water until the residual backspin sunk it, causing the
explosion.
The bouncing bomb was tested at the Building Research Establishment in May of 1942. The
following month it was used to partially demolish an obsolete dam in the Welsh Elan Valley.
In 1943, trials revealed that the bomb could be carried by modified Avro Lancaster aircraft.
This meant the British would not have to wait for a bigger bomber to enter service in order
to use the bouncing bombs...
Squadron X
A new squadron was created to carry out Operation Chastise. Formed with twenty-one bomber crews
selected from the No. 5 Group of the Royal Air Force, the team included Britons, Australians,
New Zealanders, and Americans. Assembled in March of 1943, the group was initially known
as Squadron X, but was later designated 617 Squadron, and colloquially known as the Dambusters.
The Squadron started training for low-altitude flight at night with a month left until the
Operation. Only their leader, Wing Commander Guy Gibson, was aware of the full plan.
Avro Lancaster Mk III aircraft were modified for the mission. The planes had their internal
armor, and mid-upper turret removed so they would weigh less. The bomb-bay doors were
also taken out so that the bouncing bomb could hang below the fuselage. The strange shape
and size of the Upkeep meant that it could not be traditionally delivered. After testing,
it was determine d that it should be dropped from an altitude of 60 feet while going at
a speed of 232 miles per hour. The bomb was carried by two crutches, and once it was released,
it would be spun by a motor so that it could reach the necessary speed to bounce.
Operation Chastise
The targeted dams were the Möhne, Eder, and Sorpe. Aside from the torpedo nets, each presented
unique challenges for the 617 Squadron. The Möhne Dam was surrounded by forest hills,
but the aircraft would be immediately exposed when they launched the attack. The curved
gravity dam was 40 meters high and was possibly the easiest to take down despite leaving the
bombers exposed during their attack.
The Eder dam presented a more significant challenge since it could only be reached from
the north and was harder to find. The topography of the hills around it made an attack unthinkable,
which yielded the benefit of no stationed anti-aircraft weaponry.
Finally, the Sorpe dam was the most difficult to attack. It was a different type of monster,
the embankment dam had a watertight concrete core, with a church spire standing in the
best path for an attack.
Three formations were assembled for the Operation, the first two took off on the night of May
16 while the third stood by as a reserve until the following day. Starting at 9:28 p.m.,
the 19 Lancaster planes of the three formations took off in groups of threes flying at only
1,000 feet above the ground and sea to avoid detection.
Problems arose as soon as the British aircraft entered the Netherlands. From Formation No.
2, one plane had to turn back after enemy fire destroyed its radar. Another plane was
flown too low and dove into the sea along with its bouncing bomb.
Another plane was lost to enemy fire by Texel Island. One of its companions crashed into
electricity pylons and fell near Haldern. Its bomb was dropped but remained intact.
Only the fifth plane of Formation No. 2 survived, partly because a leak at takeoff delayed the
pilot by half an hour.
Formation No.1 fared better. Only one of its nine aircraft was lost before the mission
started when one of its bombers flew into high voltage cables in Marbeck and crashed.
Guy Gibson, flying with the first wave, launched the first bomb at the Möhne Dam at 12:28
a.m. Five aircraft had to bomb the Dam to breach it. One of them was hit by enemy fire
while making its run and ended up succumbing to the blast of its own bouncing bomb. Three
crew members from that plane successfully aborted the aircraft.
The planes that remained headed towards the Eder Dam. The Valley it is in was covered
by low-lying fog. Yet, the Dam was undefended because it was believed to be too difficult
to attack for anyone to dare. One of the planes was damaged while dropping its bomb. The Dam
was eventually breached as well.
The two waves left with bombs headed towards the Sorpe Dam. The earthen Dam only saw two
Lancaster planes, due to several problems with the other aircraft. Due to the topography,
sending the Bouncing Bomb at right angles over the reservoir was too complicated. One
of the planes almost crashed against the church spire next to it. The other did 9 runs before
dripping its bomb. While it did hit, it only managed to blow up a part of the crest of
the Dam. The Dam was mostly unaffected.
Three reserve planes were sent to the Dam, but two of them never arrived. One was shot
down by Glize-Rijen. Another never found the target due to the dense fog. The one reserve
plane that arrived dropped incendiary bombs before dropping its bouncing bomb to lift
the fog and get a clear view.
The Sorpe Dam was hit but was not breached...
Effect on the War
19 crews had left base to conduct Operation Chastise. Only 11 returned. A total of 56
Royal Air Force members were lost in the Operation, with three of them taken captive by Germany.
The 617 Squadron were seen as heroes in the United Kingdom. Guy Gibson was given the Victoria
Cross for his role and was the most highly decorated Britton at the time.
The bombing raid succeeded in the United Kingdom and among the allies as it captured the news
cycle for months, increasing morale and suggesting hard-felt effects in Germany. British news
reports varied in their casualty estimates but continuously claimed that 50 or more German
towns had flooded. Articles and radio communications claimed that thousands of Germans had been
displaced, along with releasing stories about alleged civil disorder and disobedience stemming
from a collapse of the area’s government and economy.
These stories, in many cases, propagandist fantasies, were spread by the Allies. This
was done not only within their own countries but in Germany as well to demoralize their
troops. Further rumors claimed that dirty bombed water was causing typhoid and that
the war production of the country was collapsing. However, for all its bravery and novelty,
Operation Chastise did not nearly affect Germany as profoundly as the United Kingdom had hopped.
The German economy did not face a long-term destructive crisis, energy shortages were
not permanent, and steel production continued.
Despite these truths, Germany’s Ministry of Propaganda was facing an uphill battle.
The rumors merged and blew up when combined with first-hand accounts of the explosions.
It was difficult for German officials to reconcile the significant but limited effect of the
British Operation with the socially-spread narrative of severe damage and uncertainty.
To fight against weakening morale, the Germans withheld the names of the implicated dams
from the public. They banned journalists and photographers from visiting the flooded areas.
Despite this, conventional German wisdom shared by the majority of the invested population
held that around 30,000 German lives had been lost.
Even modern calculations for the losses incurred that day are imprecise estimates. That being
said, more trustworthy historical observers estimate that around 1,000 Soviet prisoners
taking part in forced labor, and approximately 600 German civilians, were lost.
The Germans quickly worked on repairs and resumed regular activity in the region by
September. Analysts have determined that for the Royal Air Force to induce the long-term
collapse of Germany that it sought, they would have needed to destroy Sorpe and other smaller
dams. The Royal Air Force would have also needed to bomb the pumping systems linking
the dams and launched routine bombings to fight reconstruction efforts. It has been
assessed that the British attacked a less than optimal combination of dams. The stand-alone
Operation that should have been just one step in a more extensive and sustained campaign.
Despite the muted outcome in the grand scheme of World War Two, Operation Chastise is remembered
by the Allied nations as one of the most prominent air raids of the conflict...