Before the Second World War, the British Air Ministry had identified the industrialised Ruhr Valley, especially its dams, as important strategic targets.The dams provided hydroelectric power and pure water for steel-making, drinking water and water for the canal transport system. Calculations indicated that attacks with large bombs could be effective but required a degree of accuracy which RAF Bomber Command had been unable to attain when attacking a well-defended target. A one-off surprise attack might succeed but the RAF lacked a weapon suitable for the task.
Attacks on the Sorpe and Ennepe Dams
The Sorpe dam was the one least likely to be breached. It was a huge earthen dam, unlike the two concrete-and-steel gravity dams that were attacked successfully. Due to various problems, only two Lancasters reached the Sorpe Dam: Joe McCarthy (in T for Tommy, a delayed aircraft from the second wave) and later Brown (F for Freddie) from the third formation. This attack differed from the previous ones in two ways: the 'Upkeep' bomb was not spun, and due to the topography of the valley the approach was made along the length of the dam, not at right angles over the reservoir.
McCarthy's plane was on its own when it arrived over the Sorpe Dam at 00:15 hours, and realised the approach was even more difficult than expected: the flight path led over a church steeple in the village of Langscheid, located on the hillcrest overlooking the dam. With only seconds to go before the bomber had to pull up, to avoid hitting the hillside at the other end of the dam, the bomb aimer George Johnson had no time to correct the bomb's height and heading.
McCarthy made nine attempted bombing runs before Johnson was satisfied.
The 'Upkeep' bomb was dropped on the tenth run. The bomb exploded but when he turned his Lancaster to assess the damage, it turned out that only a section of the crest of the dam had been blown off; the main body of the dam remained. Three of the reserve aircraft had been directed to the Sorpe Dam. Burpee (S for Sugar) never arrived, and it was later determined that the plane had been shot down while skirting the Gilze-Rijen airfield. Brown (F for Freddie) reached the Sorpe Dam: in the increasingly dense fog, after 7 runs, Brown conferred with his bomb aimer and dropped incendiary devices on either side of the valley, which ignited a fire which subsequently lifted the fog enough to drop a direct hit on the eighth run. The bomb cracked but failed to breach the dam. Anderson (Y for York) never arrived having been delayed by damage to his rear turret and dense fog which made his attempts to find the target impossible. The remaining two bombers were then sent to secondary targets, with Ottley (C for Charlie) being shot down en route to the Lister Dam. Townsend (O for Orange) eventually dropped his bomb at the Ennepe Dam without harming it.
Map from the front page of The daily Telegraph 18th May 1943
Image ( right ) Photograph of the breached Möhne Dam taken by Flying Officer Jerry Fray of No. 542 Squadron from his Spitfire PR IX, six Barrage balloons are above the dam.
The Möhne dam the day following the attacks Date 16–17 May 1943 Location Eder, Möhne and Sorpe (Röhr) rivers, Germany Result 2 dams breached Belligerents United Kingdom United Kingdom Nazi Germany Germany Commanders and leaders United Kingdom Guy Gibson Nazi Germany Josef Kammhuber Strength 19 Lancaster bombers XII. Fliegerkorps (Defending three dams) Casualties and losses 8 aircraft shot down 53 aircrew killed 3 aircrew taken prisoner. 2 dams breached 1 dam lightly damaged c. 1,600 civilians killed (including c. 1,000 prisoners and slave labourers, mainly Soviet)