Battle of the Ruhr

The Battle of the Ruhr was a 5-month long campaign of strategic bombing during the Second World War against the Nazi Germany Ruhr Area, which had coke plants, steelworks, and 10 synthetic oil plants. The campaign bombed twenty-six major Combined Bomber Offensive targets. The targets included the Krupp armament works (Essen), the Nordstern synthetic-oil plant (Gelsenkirchen), and the Rheinmetal-Borsig plant in Düsseldorf. The latter was safely evacuated during the Battle of the Ruhr. Although not strictly part of the Ruhr area, the battle of the Ruhr included other cities such as Cologne which were within the Rhine-Ruhr region and considered part of the same "industrial complex". Some targets were not sites of heavy industrial production but part of the production and movement of materiel.

Although the Ruhr had always been a target for the RAF from the start of the war, the organized defences and the large amount of industrial pollutants produced that gave a semi-permanent smog or industrial haze hampered accurate bombing. Before the Battle of the Ruhr ended, Operation Gomorrah began the "Battle of Hamburg". Even after this switch of focus to Hamburg, there would be further raids on the Ruhr area by the RAF&mdash;in part to keep German defences dispersed, just as there had been raids on areas other than the Ruhr during the battle.

Offence and defence
The British bomber force was made up in the main of the twin-engined Vickers Wellington medium bomber and the four-engined "heavies", the Short Stirling, Handley Page Halifax and Avro Lancaster. The Wellington and Stirling were the two oldest designs and limited in the type or weight of bombs carried. The Stirling was also limited to a lower operational height. Bombers could carry a range of bombs - Medium Capacity bombs of about 50% explosive by weight, High Capacity "Blockbusters" that were mostly explosive, and incendiary devices. The combined use of the latter two were most effective in setting fires in urban areas.

British raids were by night - the losses in daylight raids having been too heavy to bear. By this point in the war, RAF Bomber Command were using navigation aids, the Pathfinder force and the bomber stream tactic together. Electronic navigation aids such as "Oboe", which had been tested against Essen in January 1943, meant the Pathfinders could mark the targets despite the industrial haze and cloud cover that obscured the area by night. Guidance markers put the main force over the target area, where they would then dropping their bombloads on target markers. The bomber stream concentrated the force of bombers into a small time window, such that it overwhelmed fighter defences in the air and firefighting attempts on the ground. For most of the Battle of the Ruhr the Oboe Mosquitoes came from one squadron No. 109. The number of Oboe aircraft that could be used at any time was limited by the number of ground stations.

The USAAF had two 4-engined heavy bombers available: the B-17 Flying Fortress and B-24 Liberator - neither carried a bomb similar to the blockbuster bomb. USAAF raids were by daylight, the closely massed groups of bombers covering each other with defensive fire against fighters. Between them, the Allies could mount "round the clock" bombing. The USAAF forces in the UK were still increasing during 1943 and the majority of the bombing was by the RAF.

The German defence was through anti-aircraft weapons and day and night fighters. The Kammhuber Line used radar to identify the bomber raids and then controllers directed night fighters onto the raiders. During the battle of the Ruhr, Bomber Command estimated about 70% of their aircraft losses were due to fighters. By July 1943, the German night fighter force totalled 550. Through the summer of 1943, the Germans increased the ground-based anti-aircraft defences in the Ruhr Area ; by July 1943 there were more than 1,000 large flak guns (88 mm calibre or greater) and 1,500 lighter guns (chiefly 20 mm and 37 mm calibre). This was about one-third of all anti-aircraft guns in Germany. Six-hundred thousand personnel were required to man the AA defences of Germany. The British crews called the area sarcastically "Happy Valley" or the "valley of no Return".

Bombing during the Battle
During the battle other German targets received large attacks.
 * Berlin 27/28 March, 29/30 March
 * Stettin (now Szczecin in modern Poland) 20/21 April

Outcome
In his study of the German war economy, Adam Tooze stated that during the Battle of the Ruhr, Bomber Command severely disrupted German production. Steel production fell by 200,000 tons. The armaments industry was facing a steel shortfall of 400,000 tons. After doubling production in 1942, production of steel increased only by 20 percent in 1943. Hitler and Speer were forced to cut planned increases in production. This disruption caused resulted in the Zulieferungskrise (sub-components crisis). The increase of aircraft production for the Luftwaffe also came to an abrupt halt. Monthly production failed to increase between July 1943 and March 1944. "Bomber Command had stopped Speer's armaments miracle in its tracks".

At Essen after more than 3,000 sorties and the loss of 138 aircraft, the "Krupps works...and the town...itself contained large areas of devastation" Krupps never restarted locomotive production after the second March raid.

Operation Chastise caused some temporary effect on industrial production, through the disruption of the water supply and hydroelectric power. The Eder Valley dam "had nothing whatsoever" to do with supplying the Ruhr Area. A backup pumping system had already been put in place for the Ruhr, and Speer's Organisation Todt rapidly mobilized repairs, taking workers from the construction of the Atlantic Wall. The destruction of the Sorpe dam would have caused significantly more damage but since it was a stronger design less likely to be breached it was effectively a secondary target.

Notes and references

 * Note a According to Levine, there were few "very big industrial plants" suitable for specific targeting as was the case in Essen.