In March 1943, a special Royal Air Force (RAF) unit, 617 Squadron, was created to try a new tactic--low altitude bombing using deep penetration bombs that weighed from 9,500 to 22,000 pounds. Their first targets were three dams in the Ruhr industrial area of western Germany: the Mohne, the Eder, and the Sorpe. These dams supplied water for Ruhr steel mills and hydroelectric power. Twenty Avro Lancaster bombers were specially modified for this mission to carry a new, rotating skip bomb that would bounce across the lake, sink, and then explode at the base of the dam. So secret was the dambusting mission, that the pilots and navigators were briefed only the day before as to the actual targets.
The three dams were struck, and two were breached, on the night of 16 May 1943. "Joe " McCarthy, from Long Island, New York, was an original member of 617 Squadron. He joined the Royal Canadian Air Force (RCAF) in 1941 and soon transferred with his crew to RAF Bomber Command. From 1941 until late 1944, he flew the Hampden, Manchester, Lancaster, and Mosquito bombers and compiled a total of 80 combat missions. As Officer Commanding, German Aircraft Flight, he tested and flew over 20 different German aircraft, which had been taken from captured German airfields back to Farnborough for extensive engineering evaluation. During this period, McCarthy flew the first British operational jet, the Meteor, and the experimental Windsor bomber.
Upon returning to Edmonton, Canada, he continued flight testing a variety of aircraft for cold weather operations as well as the experimental Canadian flying wing. During 28 years in the RCAF, he flew 64 different British, American, German, and Canadian aircraft. Later assignments included base executive officer for an F-86 NATO installation in France; Commander, Flying Training School, RCAF Station Penhold, Canada; and Commanding Officer of the 407 Maritime Squadron, flying the P2V Neptune. From 1961 to 1962, he was Chief of Air Operations for the United Nations' forces in the Congo, and from 1963 to 1966, worked in plans and policy for CINCLANT/CINCLANTFLT. Wing Commander McCarthy's final assignment was as base operations officer for two maritime squadrons flying the Argus antisubmarine warfare aircraft in Nova Scotia. He retired from the RCAF in 1969 and, after a second career in real estate, fully retired in 1986.
Arriving at the Sorpe Dam after flying through the Netherlands and western Germany at very low altitude--below 100 feet--"Joe" McCarthy and his crew began their bomb run on a difficult target. Because of the construction of the dam--earth with a concrete core--he had to fly along the length of the dam and drop his bomb near the dam face to crack the center. An obstruction in a nearby town--a church steeple--and mist over the lake forced McCarthy to make 10 runs at the dam before bomb release. The resulting crack in the dam caused the Germans to drain the lake and effectively rendered the target destroyed. The crew returned to RAF Scampton, the only survivors of their five-ship flight. For his dambusting mission, Flight Lieutenant McCarthy was awarded the Distinguished Service Order by Queen Elizabeth at Buckingham Palace.