The Beginnings

60 years of Twinning

100 Things

Visits to Duisburg

Photos from Visits


What to see in

General Information

History of Duisburg

German Language

Sister Organisations

External Links


Photos 2007

The Dambusters and the Möhne Dam

These lines were writen as a result of a visit to the Möhne by a group from the Portsmouth Duisburg twinning group in June 2007.

Hitherto, attitudes towards the Dambusters have been colored by the 1955 film with Michael Redgrave portraying Barnes Wallis (which I did see on German television about six months earlier). Usefully, Channel Four have broadcast a series re-examing the operation - there is a companion book: The Dambusters by John Sweetman ISBN 0316726184.

The Producer's Preface in the above book states that

After the Dams Raid its leader Guy Gibson was sent on a propaganda tour of the United States. There he met the Hollywood film producer Howard Hawks, who wanted to make a film about the Dambusters. The film was never made, but a script was sent to the Air Ministry in Whitehall. It is now in the Public Record Office, its margins marked with the scrawled comments of senior RAF officers indignant at the way the Americans had changed the story to suit their own creative urges.

For years this has been the case with the Dams Raid, which, along with the Battle of Britain, is the RAF's most famous wartime exploit. And as John Sweetman has noted, even today it is difficult to break away from the myths and misconceptions about the Raid promulgated by the 1955 film The Dam Busters (due to necessary simplification) and Guy Gibson's book Enemy Coast Ahead (due to official vetting). Since then the story has been retold many times.

The Möhne was the only raid to affect the Ruhr. The Sorpe and Ennepe raids were unsuccessful and the Eder primarily affected Kassel. Only the Möhne was protected by flak guns, and at the Sorpe the bombs were dropped directly onto the dam, rather than spinning and bouncing them.

From our group visit, you could see directly from the dam's topography that the run-in was less than probably is assumed in popular imagination. There is a 'kink' in the lake at the dam end and a bomb dropped from the main body of the lake would not be able to hit the dam.

Nineteen aircaft were involved in the attacks, taking off from RAF Scampton, north of Lincoln. The 'First Wave' consisted of nine aircraft who would attack the Möhne first and then the Eder - if any Bouncing Bomds were left they were then to proceed to the Sorpe, which would already have been attacked by the five aircraft of the 'Second Wave'. The 'Third Wave' of of five aircraft would be held as back-up or to attack other targets. They flew over Europe at a height of about 30 meters.

The bombs needed to be released at

  • a speed of 350 km/h
  • a height of 18 m
  • a distance of between 390 and 435 meters from the dam
  • and with a backward spin of 500 rpm

The above plans shows the 'Möhne river' arm of the reservoir at the top and the smaller 'Heve river' arm at the bottom with the Hevers Berg spit between them. The dam is visible at the top left. The aircraft flew over the Körbecke Bridge at top center, over the Hevers Berg spit and turned to begin the attack from 1500 meters away. (It was only a few meters to the west of the northern end of the Körnecke bridge that we caught the boat for our cruise).

The aircraft used a bomb-aiming device that focused on the twin towers of the dam (196 meters apart). The Aldis lamps which they used to judge their height would have been especially welcomed by the German flak gunners.

These Aldis lamps were brought in on the suggestion of Benjamin Lockspeiser based on an unsuccessful experiment by Hudsons trying to catch U-boats on the surface. It was assumed that this earlier experiment had been unsuccessful because of the choppy seas, something not relevant to the waters of the reservoirs. Lockspeiser described the scene in the 1955 film where Gibson dreams up the Aldis lamps technique during a visit to the theater as 'ludicrous' but consented to the scene anyway.

  • Guy Gibson made the first attempt, releasing his bomb at 0028, the bomb bounced three times and seemed to explode on target but without causing a breach. It seems to have actually exploded too early.
  • That dropped by the second aircraft went over the dam - and the aircraft subsequently crashed. The bomb itself though destroyed a power station below the dam.
  • The third bomb veered off course and exploded too far west.
  • The fourth appeared to hit the target but the dam still held.
  • On the fifth attack, the pilot saw the dam beginning to disintegrate but dropped his own bomb anyway to seal the 'success'.

With one aircaft lost en route, three aircraft still had bombs and (along with Gibson and his second-in-command) they proceeded to the Eder, a quarter of an hour away.

Of the nine aircraft of the 'First Wave' only five returned. In total, 8 of the original 19 failed to return.

Of the dam's length of 650 meters, a breach 76 meters long and 22 meters high had been made. Practically all the water in the reservoir (88%) leaked out within 12 hours. It took 6 hours for traces of the flood water to travel the 150 km to the Rhein at Duisburg (although our acquaintances from Duisburg originally told us that the main force was stopped by the Baldeney dam, south of Essen).

Incidentally, the dam was 34 meters wide at its base and 6.25 meters at the top.

The dam was repaired by October 1943, although the water level was kept lower than before.

Unfortunately, one of the bouncing bombs was captured intact and this raised immediate concerns that the Germans could use this technology against British dams. Rather mysteriously, the bouncing bomb was never used again, despite Barnes Wallis apparently pushing for its use against other targets.

Early in 1943 Harris, head of Bomber Command, had been highly critical of the plans. He said

'This is tripe of the wildest description. There are so many 'ifs' and 'ands' that there is not the smallestchance of its working.'

At about the same time he was told by Charles Craven, the chairman of Vickers, to

'stop this silly nonsense about the destruction of the dams'
Details of the bomb (actually a depth charge)
  • Encased in metal of width 0.95 cm
  • length 152.1 cm
  • diameter 127 cm
  • weight 4200 kg
  • designed to explode at a depth of 9.15 m
  • self destruct fuses to operate 90 secs after release if not already exploded by then (although, as related above, this mechanism failed in one case)

In the above picture, you can just make out the torpedo defenses placed in front in of the dam.