Operation Chastise
Part of World War II
The Möhne dam on the day after the attacks.
Date 17 May 1943 Location Eder River, Germany Result British Victory
Combatants
No. 617 Squadron	Nazi Germany
Commanders
Guy Gibson	N/A
Strength
19 aircraft	Various anti-aircraft defences
Casualties
8 aircraft shot down 53 killed 3 captured	2 Dams breached 1294 killed

Operation Chastise was the official name for the attacks on German dams on 17 May 1943 in World War II using a specially developed "bouncing bomb". The attack was carried out by Royal Air Force No. 617 Squadron, subsequently known as the Dambusters.

Background

Prior to the war, within the Air Ministry the industrial heartland of Germany had been identified as an important strategic target and the dams of the area considered as particular targets. Besides providing power they were used to provide water into the canal transport system. The methods to attack the dams had been duly considered. Calculations indicated that repeated strikes with large bombs would be effective but the necessary accuracy with the standard bombers of Bomber Command in face of enemy defences was unlikely.

Development of the plan

The mission developed out of a bomb 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 bombers 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 (12,200 m). This was part of the earthquake bomb concept. However, at the time there was no aircraft capable of flying at this height with such a heavy load. A much smaller charge would suffice if it could be exploded directly against the dam wall below the surface of the water. The major German dams were protected by heavy torpedo netting to prevent such an attack, and Wallis's breakthrough was to overcome this. A drum-shaped bomb, spinning rapidly backwards (over 500 rpm) and dropped from a sufficiently low altitude at the right speed, would skip for the required distance over the surface of the water in a series of bounces before reaching the dam wall and then, using its residual spin, run down the wet side to the dam's base. An accurate drop could bypass the dam protection and let the bomb be detonated against the dam with a hydrostatic fuse. After testing, and many meetings, the idea was adopted on February 26, 1943. The bomb was codenamed 'Upkeep'. The dams were to be bombed in May of that year, when water levels would be highest and create the most damage to the German war effort.





The operation was given to 5 Group which formed a new squadron 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 RAF Scampton, 5 miles north of Lincoln.

The targets were the three key dams near the Ruhr area, the Möhne, the Sorpe 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 have greater effect.



The aircraft were adapted Avro Lancaster Mk IIIs, known as B Mark III Special (Type 464 Provisioning).^[1] 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 ^[2], it was spun up to speed by an auxiliary motor.

Bombing from 60 feet (18 m) at 240 mph (390 km/h), 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 aircraft was the correct distance from the target. The two key dams at Möhne and Eder had a tower at each end. A special aiming device (a device with two prongs making the same angle as the two towers at the correct distance from the dam) showed when to release the bomb. The second problem was to measure the aircraft's altitude (the usual barometric altimeters lacked sufficient accuracy). Two spotlights were mounted, one under the nose and another under the fuselage, such that at the correct height their light beams would converge on the surface of the water. The crews practised over the Eyebrook Reservoir in Leicestershire/Rutland (built in 1940 to supply Corby steelworks, Stewarts and Lloyds), the Derwent Reservoir, Derbyshire, and the Fleet Lagoon at Chesil Beach, Dorset.

The bombs were delivered to the squadron on 13 May, after the final tests on 29 April. With promising weather reports the pilots, navigators and bomb aimers were informed of the targets on 15 May, the rest of the crews on the following day.

The attacks

Organisation

The Lancasters were organised into three groups. Formation 1 was to attack the Möhne 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, Ennepe and Diemel.

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 operations room for the mission was at 5 Group headquarters in Grantham, Lincolnshire. The codes (transmitted in morse) for the mission were agreed on as Goner for bomb dropped, Nigger for the Möhne breached and Dinghy for the Eder breached. The Nigger code was after Gibson's black dog ^[3] that had been run over and killed on the morning of the 17th. Dinghy was from the nickname of Gibson's friend Young who would be flying A-Apple — Young had had to make forced landings in the sea several times on operations, he and his crew having to resort to the aircraft's inflatable liferaft. Thereafter, he had been known as "Dinghy Young".

The outbound flights

The aircraft flew two routes, carefully skirting known flak hot spots.

Formation 1 entered continental Europe between Walcheren and Schouwen, crossed the Netherlands, 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 Möhne. Formation 2 flew further northwards, cutting over Vlieland and crossing the IJsselmeer before joining the first route near Wesel and then flying south beyond the Möhne to the Sorpe.

The first aircraft, those of Formation 2 and heading for the longer northern route, took off at 21h10. McCarthy's aircraft had a hydraulics fault and he took off in a reserve craft twenty minutes later. Formation 1 took off from 21h25.

The first casualties were taken soon after the craft reached the Dutch coast. Formation 2 did not fare well: Munro's aircraft lost his radio to flak and turned back over the Zuider Zee while Rice flew too low and lost his bomb in the water but recovered the aircraft to return to base. The aircraft of both Barlow and Byers crossed over the coast around the island of Texel. Byers was hit by flak and shot down shortly thereafter crashing into the Waddenzee. Only the tardy aircraft of McCarthy survived across the Netherlands. By contrast, Formation 1 lost Astell, somewhere over Roosendaal.

The attack on the Möhne dam

Formation 1 arrived over Möhne lake and Gibson's aircraft (G for George) bombed first. Hopgood (M for Mother) attacked second. Hopgood's aircraft was hit by flak as it made its low-level run and was then caught in the blast of its own bomb and destroyed. Subsequently Gibson flew his aircraft across the dam to draw flak from Martin's run. Martin (P for Peter (Popsie)) 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 attack on the Eder dam

The Eder valley was heavily fogged but not defended. The tricky topography of the surrounding hills made the approach difficult and the first aircraft, Shannon's, made six runs before taking a break. Maudslay (Z for Zebra) then attempted a run but 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. The final bomb of the formation, from Knight's aircraft (N for Nan), breached the dam.

The attacks on the Sorpe and Ennepe dams

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) dropped his bomb on the Ennepe without breaching the dam.

Attack on the Bever dam?

There is some evidence that Townsend may have mistakenly attacked the Bever Dam rather than the Ennepe. Townsend reported difficulty in finding the dam and in his post-raid report complained that the map of the Ennepe dam was incorrect. The Bever dam is located only about 5 miles southwest of the Ennepe dam and the reservoir has similar geography. However, the Bever dam is located on the south side of the reservoir while the Ennepe is located on the north side of its reservoir. With the mist filling the valleys in the early morning hours, it would be understandable to mistake the two reservoirs. The War Diary of the German Naval Staff reported that the Bever Dam had been attacked at nearly the same time as the Sorpe. In addition, the Wupperverband authority responsible for the Bever recovered the remains of a mine. Paul Keiser, a 19 year old soldier on leave at his home very near the dam, also reported an aircraft making several approaches to the dam and eventually dropping a weapon leaving a big explosion and a great pillar of flame in a column of water. The Dambusters Raid author, John Sweetman, claims that Townsend's report of the moon reflecting on the mist and water is consistent with an attack heading for the Bever rather than the Ennepe given the moon's azimuth and altitude during the attack. Sweetman also points out that the Ennepe-Wasserverband authority is adamant that only a single bomb was dropped near the Ennepe during the whole war and this bomb fell in the woods by the side of the dam, not in the water as in Townsend's report. Finally, members of Townsend's crew independently reported seeing a manor house and attacking an earthen dam, which is consistent with the Bever rather than the Ennepe. The main evidence supporting an attack of the Ennepe is Townsend's post- flight report that he attacked the Ennepe on a heading of 355 deg. M. Assuming that the heading was incorrect, all other evidence points toward an attack on the Bever.

The return flights

On the way back, flying again at treetop level, one further aircraft was lost, that of Young which was hit by flak and crashed into the sea just off the coast of Holland.

Complete list of the aircraft involved

Aircraft Call Sign	Commander	Target	Returned?	Notes
First Wave
G George	Wing Commander Guy Gibson	Möhne Dam	Yes	Raid leader. Mine exploded short of dam. Used aircraft to draw AA fire away from other crews.
M Mother	Flight Lieutenant Hopgood		No	Hit by AA fire outbound. Mine bounced over dam. Shot down over target while attacking.
P Peter (Popsie)	Flight Lieutenant Martin		Yes	Mine missed target.
A Apple	Squadron Leader Young		No	Mine hit dam and caused small breach. Shot down over Dutch coast while returning.
J Johnny	Flight Lieutenant Maltby		Yes	Mine hit dam and caused large breach.
L Leather	Flight Lieutenant Shannon	Eder Dam	Yes	Mine hit target—no effect.
Z Zebra	Squadron Leader Maudsley		No	Mine overshot target and damaged aircraft. Shot down over Germany while returning.
N Nancy (Nan)	Pilot Officer Knight		Yes	Mine hit dam and caused large breach.
B Baker	Flight Lieutenant Astell	N/A	No	Crashed after hitting power lines outbound.
Second Wave
T Tommy	Flight Lieutenant McCarthy	Sorpe Dam	Yes	Mine hit target—no effect.
E Easy	Flight Lieutenant Barlow	N/A	No	Crashed after hitting power lines outbound.
K King	Pilot Officer Byers		No	Shot down over Dutch coast outbound.
H Harry	Pilot Officer Rice		Yes	Lost mine after clipping sea outbound. Returned without attacking target.
W Willie	Flight Lieutenant Munro		Yes	Damaged by AA fire over Dutch coast. Returned without attacking target.
Third Wave
Y York	Flight Sergeant Anderson	Lister Dam	Yes	Could not find target due to mist.
F Freddy	Flight Sergeant Brown	Sorpe Dam	Yes	Mine hit target—no effect.
O Orange	Flight Sergeant Townsend	Ennepe Dam	Yes	Mine hit target—no effect.
S Sugar	Pilot Officer Burpee	N/A	No	Shot down over Holland outbound.
C Charlie	Pilot Officer Ottley		No	Shot down over Germany outbound.

Bomb damage assessment

Bomber Command wanted to conduct bomb damage assessment as soon as possible. Accordingly, the Commanding Officer of No. 542 Squadron was informed by Bomber Command HQ of the exact time of the attacks. A photographic reconnaissance Spitfire of No. 542 Squadron took off from RAF Benson at 07:30 and arrived over the Ruhr just after first light. Photographs were taken of the breached dams and the huge floods.^[4]

After the raid

In all, 53 of the 133 aircrew were killed and three bailed out to be made Prisoners of war. Of the surviving aircrew thirty-three were decorated at Buckingham Palace on 22 June, with Gibson awarded the Victoria Cross. There were five Distinguished Service Orders, ten Distinguished Flying Crosses and four bars, twelve Distinguished Flying Medals and two Conspicuous Gallantry Medals.

After a public relations tour of America, Gibson returned to operations and was killed on a mission in 1944.

Following the dams raid, 617 Squadron was kept together as a specialist unit. The squadron badge ("on a roundel, a wall in fesse, fracted by three flashes of lightning in pile and issuant from the breach, water proper") was chosen and a motto "Après moi le déluge" (After me the Flood). According to Brickhill there was some controversy over the motto, with the original version Après nous le déluge being rejected by the heralds as having inappropriate provenance (having been coined, reportedly, by Madame Pompadour), and après moi le déluge having been used by Louis XV in an "irresponsible" context. The motto having been chosen by the King, the latter was finally deemed acceptable.

The squadron went on to drop Wallis' massive Tallboy bomb and Grand Slam bomb, using an advanced bomb sight which enabled the bombing of small targets with far greater accuracy than was routinely obtained with conventional bomb aiming techniques. The squadron is still active today.

Effect on the war

The tactical view

The Möhne and Sorpe lakes poured around 330 million tons of water (equivalent to a cube 687 metres on each side) 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 (80 km) from the source. The Eder drains towards the east into the Fulda, flooding farmland and several villages. Estimates show that before 15 May 1943 water production on the Ruhr was 1 million tonnes, which dropped to a quarter of that level after the raid. In terms of deaths: 1,294 people were killed,^[5] 749 of them Ukrainian POWs from a camp just below the Eder Dam.^[6] After the operation Barnes Wallis wrote, "I feel a blow has been struck at Germany from which she cannot recover for several years".

However, on closer inspection, Operation Chastise did not have the military effect that was at the time believed. By 27 June full water output was restored, thanks to an emergency pumping scheme inaugurated only the previous year, and the electricity grid was again producing power at full capacity. The raid proved to be costly in lives (more than half the lives lost belonging to allied POWs), but in fact no more than a minor inconvenience to the Ruhr's industrial output. However, it is a commonly understood military concept that any single attack in an operation, while having only minimal effect in and of itself to the larger strategic effort, can contribute to a large overall cumulative result, eventually causing a tipping point in the scale of events. (That is why, for example, soldiers continue to fire their weapons in battle even though any single rifle shot cannot possibly win an entire war.) (See also Chaos Theory, and The Tipping Point, by Malcolm Gladwell.)

In his book Inside the Third Reich, Albert Speer expressed puzzlement at the raids; destruction of one of the dams served no purpose at all, he claimed, and the failure to follow up with additional raids represented a major lost opportunity for the Allies.

The strategic view

The Dams Raid was, like many British air raids, undertaken with a view to the need to keep drawing German defensive effort back into Germany and away from actual and potential theatres of ground war, a policy which culminated in the Berlin raids of the winter of 1943–44. In May 1943 this meant keeping the Luftwaffe and anti-aircraft defence forces' effort away from the Soviet Union; in early 1944, it meant clearing the way for the aerial side of the forthcoming Operation Overlord.

By far the greatest and most unexpected effect was on German food production. The Ruhr valley below the dams was a major source of vital food for Germany, and large areas of arable land were rendered unusable and huge numbers of farm animals were killed. This had an immediate negative effect on German morale. In addition, the pictures of the broken dams proved to be a morale boost to the Allies, especially to the British, still suffering under German bombing.

An associated, but equally major effect was that Barnes Wallis's ideas on earth quake bombing, which had been rejected before, now became accepted by 'Bomber' Harris. Prior to this raid bombing practice had been to 'area bomb' with many light bombs, in the hope that one would hit the target. Work on the earth quake bomb theory resulted in the Tallboy and Grand Slam weapons, which caused unprecedented damage to German infrastructure in the later stages of the war. They rendered the V-2 assembly building unusable, buried the V-3 guns, sunk the Tirpitz and destroyed many bridges and other hardened installations. Notable amongst their successes are the U-Boat pens at Brest, where they penetrated 20 ft thick roofs of reinforced concrete, and the Saumur Tunnel, which was attacked by dropping the bombs straight through 60ft of hill to explode in the tunnel below.

The diplomatic view

An important reason for planning the raid was to persuade Stalin that Britain was capable of being an effective ally. This was the middle period of the war when the Japanese had relatively recently brought the United States into it on Britain's side (see Attack on Pearl Harbor). Germany had a little earlier done the same with the Soviet Union (see Operation Barbarossa). However, the Soviet Union was in a very serious position, although by the time the preparations for the raid were complete the USSR had found the capacity to begin its counter-offensive on the Don and Volga. (See Battle of Stalingrad). The Dams Raid enabled Churchill, in negotiations with the leaders of these new allies, to point to an effective strike against the hitherto apparently invincible German state so that he was taken more seriously as an ally than might otherwise have been the case. This was relevant vis-à-vis Stalin but also in the USA. Although Churchill had the sympathetic ear of Roosevelt, many of the US military staff had until then been less persuaded of the value of British experience and capabilities.^[7]

International law

In 1977, Protocol I to the Geneva Conventions prohibited attacks against installations such as dams, dykes and nuclear power stations "if such attack may cause the release of dangerous forces and consequent severe losses among the civilian population". The special protection covering dams and dykes terminates "only if it is used for other than its normal function and in regular, significant and direct support of military operations and if such attack is the only feasible way to terminate such support".

The United Kingdom ratified Protocol I in 1998, but made the following reservation in respect of Article 56:

"The United Kingdom cannot undertake to grant absolute protection to installations which may contribute to the opposing Party's war effort, or to the defenders of such installations, but will take all due precautions in military operations at or near the installations referred to in paragraph 1 of Article 56 in the light of the known facts, including any special marking which the installation may carry, to avoid severe collateral losses among the civilian populations; direct attacks on such installations will be launched only on authorisation at a high level of command."

Operation Chastise in popular culture

• A 1954 film, The Dam Busters was made about the raids and was very popular. Its depiction of the raid, along with a similar sequence in the film 633 Squadron, provided the inspiration for the Death Star trench run in Star Wars: . The film is also watched on television by the character Pink in the 1982 film, Pink Floyd The Wall.
• In 1984, a Commodore 64 computer combat flight simulator The Dam Busters was made based on this operation.
• A 1989 British commercial for Carling Black Label lager reused footage from the attack sequence of the 1954 film, with a wily German sentry on top of the dam catching the perfectly spherical bombs in the manner of a football (soccer) goalkeeper. The pilot of the attacking Lancaster then delivers the brand slogan: "I bet he drinks Carling Black Label!" The commercial ran for many years, frequently appearing in advert breaks for both the 1954 film and documentaries about Operation Chastise. A subsequent Carling commercial also used bouncing bomb imagery, this time to enable a British holidaymaker to beat the Germans to the sunbeds.
• The PC game Call of Duty features a mission in the British campaign, sometime after Operation Chastise, where players must suppress the Eder Dam's AA defenses and destroy the dam's generators in order to clear the way for the RAF to make a second (fictional) raid against the dam.
• The console game Secret Weapons Over Normandy features a mission in which the player must destroy a dam and the suggested weapon is the bouncing bomb. However the dam involved is stated to be in Norway and the mission objective is based on the sabotage at Vemork, so the game has conflated this sabotage and the Dambusters mission.
• On 1 September 2006, it was announced that Peter Jackson would produce a remake of the 1954 movie, to be directed by Christian Rivers with production starting in 2007.

Notes

References

• Brickhill, Paul. The Dam Busters. London: Evans Bros., 1951. "Novelised" style. Covers entire wartime story of 617 Squadron.
• Churchill, Winston S. The Second World War, Volume IV: The Hinge of Fate. London: Cassell, 1951.
• Gibson, Guy. Enemy Coast Ahead. London: Pan Books, 1955. Gibson's own account.
• Sweetman, John. The Dambusters Raid. London: Cassell, 1999. ISBN 0-304-35173-3.

External links

• Official site of the Royal Air Force about Operation Chastise
• Site with details of the raids, full crew listing, links to present day 617 Sqn and much more
• Online Dambusters exhibition at the UK National Archives
• Secrets of the Dead: Bombing Nazi Dams and their link page
• BBC Online - Myths and Legends - Home of the Dambusters
• 60th Anniversary BBC News.
• Dambuster & Guy Gibson website in Dutch /
• Dam Busters Filmclips
• Gunner Douglas Webb
• Die Nacht vom 16. auf den 17. Mai 1943 - "Operation Züchtigung": Die Zerstörung der Möhne-Talsperre (in German)
• G for George at the Australian War Memorial, Canberra
• Luftkriegsgeschichte aus dem Ederberland und Waldeck Frankenberg
• Eyebrook
• Dambusters site with details of Operation Chastise including video footage and more

See also

•  • [ e] Strategic bombing during World War II by the Royal Air Force
Overviews and documents	RAF Bomber Command • Bomber Command • Strategic bombing • Aerial bombing of cities • Butt report • dehousing paper
Prominent People	Sir Archibald Sinclair • Sir Charles Portal • Norman Bottomley • Arthur "Bomber" Harris • Sir Arthur W. Tedder • Professor Lindemann
Bombing Campaigns and Operations	Augsburg • Berlin • Chastise • Cologne • Crossbow • Dresden • Gomorrah (Hamburg) • Heilbronn • Hurricane • Kassel • Pforzheim • Wrzburg
Aircraft	Blenheim • Boston • Halifax • Hampden • Lancaster • Mosquito • Stirling • Ventura • Wellesley • Wellington • Whitley
Technology	Window • H2S • GEE • Oboe • G-H • Monica • Blockbuster bomb • Bouncing bomb • Fire bomb • Grand Slam bomb • Tallboy bomb
Tactics	Area bombing • Bomber stream • Pathfinders • Shuttle bombing
Other	• USAAF • Luftwaffe