Busters ( Operation Downwood ) WW2
Operation Downwood was the official
name for the famous attacks on German dams on May 17,
1943 in World War II using a specially developed
"bouncing bomb". The Dam Busters were Royal Air
Force 617 Squadron.
The mission developed out of the bomb. The bomb was
designed by Barnes Wallis and developed into a working
device by a team at Vickers. Wallis was an aircraft
designer and had the successful Wellesley and Wellington
to his credit, while working on the Warwick he also began
work on bomb design with dams specifically in mind.
His initial idea was for a 10-ton bomb to be dropped from
40,000 feet, but research showed that without a direct
hit a bomb would need to be uncarriably vast to breach a
dam. However, a much smaller charge would suffice if it
could be exploded directly against the dam wall below the
surface of the water. But the major German dams were
protected by heavy torpedo netting to prevent such an
attack and it was Wallis's breakthrough to see a way past
this. A drum-shaped bomb, spinning rapidly and dropped
from a sufficiently low altitude at high speed would, for
a short distance, skip over the surface of the water in a
series of bounces before halting and sinking. An accurate
drop could bypass the dam protection and be detonated
against the dam with a hydrostatic fuse. After testing
and many meetings the idea was adopted on February 26,
1943. The dams were to be bombed in May of that year,
when water levels would be highest.
The operation was given to 5 Group
and a new squadron was formed to undertake the mission.
Initially called Squadron 'X' it was led by wing
Commander Guy Gibson, a veteran of over 170 missions. A
further 21 crews were chosen from 5 Group to join the new
squadron based at Scampton.
The dams were to be three key dams in the Ruhr area, the
Moehne and the Sorpe on the Ruhr River and the Eder Dam
on the Eder River. The loss of hydroelectric power was
important but the loss of water to industry, cities and
canals would be of greater impact.
The WW2 aircraft were adapted Avro Lancaster Mk IIIs,
dubbed Special Bs. To reduce weight much of the armour
was removed as was the mid-upper turret. The substantial
bomb and its unusual shape meant that the bomb doors were
removed and the bomb itself hung, in part, below the body
of the aircraft. It was mounted in two crutches and
before dropping it was spun up to speed by an auxiliary
Bombing from 60 feet at 240 mph, at a very precise
distance from the target, required expert crews,
intensive night and low-altitude flying training, and the
solutions to two technical problems. The first was to
know when the airplane was the correct distance from the
target. The two key dams at Moehne and Eder had a tower
at each of their ends. A special aiming device (basically
a triangle similar to that created by the two towers and
an airplane at the correct distance from the dam) showed
when to release the bomb. The second problem was to
measure the airplane's altitude (the usual barometric
altimeters were insufficiently accurate). Two spotlights
were mounted under the nose and under the fuselage such
that their beams would intersect 60 feet from the
underside of the plane. At the correct height, the two
spots of light would merge into one on the surface of the
The bombs were delivered to the squadron on May 13, after
the final tests on April 29. With promising weather
reports the pilots, navigators and bomb aimers were
informed of the targets on May 15, the rest of the crews
on the following day.
The WW2 Lancasters were organised into three groups.
Formation 1 was to attack the Moehne and after that
aircraft still with bombs would attack the Eder.
Formation 2 was to attack the Sorpe. The third group was
a mobile reserve, it would take off two hours later and
bomb as directed, either attacking the main dams or
bombing smaller dams at Schwelm, Ennerpe and Dieml.
The operations room for the mission was at 5 Group
headquarters in Grantham. The codes, transmitted in
morse, for the mission were agreed on as Goner for bomb
dropped, Nigger for the Moehne breached, Dinghy for the
Eder breached and ?? for the Sorpe breached. The Nigger
code was after Gibson's black dog that had been run-over
and killed on the morning of the 17th.
The aircraft flew two routes, carefully skirting known
flak hot-spots, and no more than 75 feet off the ground.
Formation 1 entered continental Europe between Walcheren
and Schouwen, crossed Holland, skirting the airbases at
Eindhoven and Gilze-Rijen, curved round the Ruhr defences
and turned north to avoid Hamm before turning to head
south to the Moehne. Formation 2 flew further northwards,
cutting over Vieland and crossing the Zuyder Zee before
joining the first route near Wesel and then flying south
beyond the Moehne to the Sorpe.
Formation 1 was of nine aircraft in three groups -
Gibson, Hopgood, Martin; Young, Astell, Maltby; and
Maudslay, Knight, Shannon. Formation 2 was of five
aircraft, those of McCarthy, Byers, Barlow, Rice and
Munro. Formation 3 consisted of the aircraft of Townsend,
Brown, Ottley and Burpee. Two crews were unable to make
the mission because of illness.
The first aircraft, those of Formation 2 and heading for
the longer northern route, took off at 21.10, McCarthy's
aircraft had a hydraulics fault and he took off in a
reserve craft twenty minutes late. Formation 1 took off
The first casualties were soon after the craft reached
the Dutch coast, Formation 2 was very badly attrited -
Munro's aircraft lost his radio to flak and turned back
over the Zuyder Zee, Rice flew too low and lost his bomb
in the Zuyder Zee but recovered the aircraft to return to
base. The aircraft of both Barlow and Byers crossed over
the coast around Harderwijk and were soon shot down. Only
the tardy aircraft of McCarthy survived across Holland.
Formation 1 lost only Astell, somewhere over Rosendaal.
Formation 1 arrived over Moehne Lake and Gibson's
aircraft (G for George) bombed first. Hopgood (M for
Mother) attacked second, the aircraft was hit by flak as
it made its 60 feet run and then caught in the blast of
it's own bomb and destroyed. Martin (P for Peter) bombed
third, his aircraft was hit but made a successful attack.
Then Young (A for Apple) made a successful run and after
him Maltby (J for Johnny) and then finally the dam was
breached. Gibson then led Young, Shannon, Maudslay and
Knight to the Eder.
The Eder valley was heavily fogged but not defended. The
tricky topology of the surrounding hills made the
approach difficult and the first aircraft, that of
Shannon, made six runs before taking a break. Maudslay (Z
for Zebra) then attempted a run, the bomb struck the top
of the dam and the aircraft was caught in the blast.
Shannon made another run and successfully dropped his
bomb and the final bomb of the formation, on Knight's
aircraft, breached the dam.
McCarthy (T for Tom) reached the Sorpe alone. It was the
least likely to be breached - a vast earth dam rather
than the two concrete structures successfully attacked.
Despite the mist and ill-placed hills McCarthy's aircraft
successfully dropped its bomb but did not breach the dam.
Three of the reserve aircraft were directed to the Sorpe,
Burpee (S for Sugar) never reached the dam, Brown (F for
Freddy) reached the dam and in increasingly dense mist
finally dropped his bomb without breaking the dam.
Anderson (Y for Yorker) arrived last and the mist was too
dense for him to even attempt the run. The remaining two
aircraft were sent to subsidiary targets, Ottley (C for
Charlie) was shot down en route while Townsend (O for
Orange) successfully dropped his bomb on the Ennerpe.
On the way back only one further aircraft was lost, that
of Young was hit by flak and crashed into the sea just
off the cost of Holland. In all, of 133 aircrew 53 had
been killed and three bailed out to be made POWs.
Bomb Damage Assessment
The Moehne and Eder lakes poured around 330 million tons
of water into the western Ruhr region, mines were flooded
and houses, factories, roads, railways and bridges
destroyed as the flood waters spread for around 50 miles
from the source. In terms of deaths only 1,294 people
were killed, 749 of them Russian POWs from a camp just
below the Eder Dam.
Of the surving aircrew thirty-three were decorated at
Buckingham Palace on June 22, with Gibson awarded the
Victoria Cross. There was five DSOs, ten DFCs and four
bars, twelve DFMs and two CGMs. The squadron badge
("on a roundel, a wall in fesse, fracted by three
flashes of lightening in pile and issuant from the
breach, water proper") was chosen and a motto
"Apr?s moi le d?luge".
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