The Abortive Offensive of June-October 1943
In April 1943 four new B-17 groups reached Britain. They became operational in May. The 92nd Bomb Group, which had arrived in 1942 but had been relegated to training duties, returned to operations. In May and June seven more B-17 groups and four groups of B-26 medium bombers arrived. The Eighth Air Force was now ready to go beyond fringe areas.
A mission on June 11 to Bremen and Wilhelmshaven, far beyond escort range, showed that attacks on Germany were not going to get easier. A force of 252 bombers, the largest yet dispatched, found Bremen overcast. Only 8 bombers went down, but the fierce fighter attacks disrupted the bomb run, and the attackers missed the U-boat construction yards. In an attack on Bremen and Kiel two days later, the force sent to Kiel met the toughest opposition yet seen, losing 22 bombers. The larger force attacking Bremen lost four B-17s, while a smoke screen prevented accurate bombing.
On June 22 the Eighth made its first attack on a major objective in Germany that was not related to aircraft and submarines. Curiously, in view of its relatively low priority, this was an almost entirely isolated, and very effective, blow against synthetic rubber production. Surprise (the Eighth had only penetrated deep inland thrice before), diversions, and clever routing that led the Germans to think for a time that the Americans were heading for the North Sea coast, contributed to the success of the attack. Of the 235 bombers dispatched, 183 planes (including 11 YB-40 escort Fortresses) reached the synthetic rubber plant at Hüls, which made 30 percent of Germany's synthetic rubber. After the attack the plant was shut for a month, and its recovery was not finished for six months. The Germans were worried; their reserves of rubber were reduced to one and a half months' requirements.
The attack on Hüls showed the vulnerability of the synthetic rubber plants, if the Americans could get at them. The Strategic Bombing Survey later estimated that three to five more major attacks on Hüls would have shut it permanently.