History of the Squadron during World War II (Aircraft: Lancaster I, III)
Arguably the most famous bomber squadron of the RAF, 617 Squadron was formed for the single purpose of attacking the major Dams in Germany using the UPKEEP “bouncing bomb” invented by the Vickers engineer Barnes Wallis (Later Sir Barnes). The squadron was formed on 21 March 1943, under the command of Wing Commander Guy Gibson DSO, DFC. Gibson had already a long history of wartime service, having completed two tours of operations on bombers and one on night fighters. He was given a free hand in selecting crews for the new squadron, and recruited a number of highly experienced pilots, although not all of the aircrew had a lot of operational experience. As soon as the squadron crews had assembled at their base at Scampton, Lincolnshire, UK , training for the operation (later given the code name Operation CHASTISE) started, although until the night of the operation itself the crews (except for Gibson himself) did not know what the targets would be. The raid was going to be almost unique in that the participating aircraft would be flying at about 60 feet (18.3 metres) over Germany on the way to the targets. Normally, bombers flew over Germany at heights above 15,000 feet (4600 metres), so the first priority of the training was to accustom the crews to flying at the extreme low level, first by day and then by night.
Meantime, the weapon itself (UPKEEP) was being developed with great urgency from what was essentially a theory to a practical weapon: at the time when 617 squadron was inaugurated, the full-sized weapon had not been completely designed, nor had even prototypes been produced.
A Weapon to Destroy the DamsThe main centre of German heavy industry, the Ruhr, depended heavily on its water supply. This supply came mainly from the reservoirs behind two main dams: the Möhne and the Sorpe. To destroy the dams required that a large explosive charge be placed right against the dam face on the water side (explosions in the water further from the dam wall rapidly lose effect the further from the dam wall they are). But how was this precise accuracy to be achieved? A novel idea was put forward by Barnes Wallis, an engineer at Vickers aviation, that a bomb could be skipped along the surface of the water: he tested the feasibility of the idea first of all with marbles on a washtub full of water, then with golf-ball sized spheres, then with a half-scale model of the bomb that could be dropped from a
Essentially, the weapon and the squadron had the same time scale to be ready for the operation, which had to take place around the middle of May, because the dams needed to be attacked when the water was at its highest level. So there was great pressure on both the weapons designers and the airmen. Gibson himself attended some of the tests of UPKEEPs, many of which were failures because the bombs did not perform as was hoped. Eventually the problems were solved, and a final design could be defined and sufficient of the bombs could be manufactured in time for the raid.
After almost two months’ training for 617 squadron, Operation CHASTISE took place on the night of the 16/17 May 1943. Nineteen Lancaster bombers, specially modified to carry the UPKEEP bomb, participated, attacking 4 of the major dams in the Ruhr area. Of the participating aircrew, 26 of the 133 were Canadian, and one was an American serving in the RCAF. The operation was a success in that the Möhne and Eder dams were breached (the Eder Dam was not in the Ruhr catchment area but was attacked because it was a good target for UPKEEP). The Sorpe dam was the third main objective, and was attacked by two crews and damaged, but not enough to form a breach: it was differently constructed from the Moehne and Eder dams and was less susceptible to being breached by UPKEEP. One aircraft attacked what is thought to be the Ennepe dam without result. Two of the attacking aircraft had to abort their missions. The water from the breached Möhne and Eder dams caused widespread destruction as the reservoirs emptied. Unfortunately for 617 squadron, the cost in killed aircrew was high. Of the 19 aircraft which set off on the operation, no fewer than eight were shot down or crashed: only 3 aircrew (1 of whom was Canadian) survived of the 56 (15 Canadians) who were in the missing aircraft.
The operation catapulted 617 Squadron and its crews into the limelight: many of the airmen received decorations, starting with Gibson, who was awarded the Victoria Cross for his fortitude in leading the raid. However, it must be acknowledged that a loss rate of 42% for one operation, however successful, is not sustainable, and operations such as CHASTISE cannot be repeated: it was very much a one-off. Nevertheless, the operation was a great morale-booster for the British public.
There is a considerable literature on the Dams Raid, starting with Guy Gibson’s own description in his autobiographical account of life in Bomber Command (Enemy Coast Ahead – Uncensored, Crécy Publishing Ltd, 2003). Other more recent accounts of the raid and the events leading up to it are Dam Busters by James Holland (Bantam Press, 2012), Dam Busters by Ted Barris (Harper Collins, Toronto, 2018), and Chastise by Max Hastings (William Collins, London, 2019)
After the Dams Raid, a decision was made by Bomber Command that 617 would be retained as a specialist bombing unit, staffed by highly experienced aircrew, to undertake missions where precision bombing was required. However, after the Dams Raid, the squadron flew only a few operations to targets in Italy in July 1943, flying on to airfields in North Africa, and then attacking Italy again on the return to England. They also moved from Scampton, which was a grass airfield to Coningsby , which had hard runways, in August 1943. The squadron’s next major operation against Germany was on 15 September 1943. The objective was to make a low-level attack on the Dortmund-Ems Canal near Ladbergen, Germany . The squadron was tasked with dropping 12,000 lb high-capacity bombs into the canal so as to cause a breach. Unfortunately the operation was a disaster: the weather was poor and the target was heavily defended by flak. The canal was not breached and 5 out of the 8 Lancasters involved failed to return, including that of the CO, Wing Commander George Holden DSO, DFC & Bar, who took with him several of Gibson's original crew of the Dams Raid. Not surprisingly, after this operation, the squadron developed a reputation as a suicide unit and recruitment of fresh crews was difficult for a while.
From this low point the squadron emerged as an effective special precision bombing unit. Under the command of Wing Commander Leonard Cheshire DSO and 2 Bars, DFC, they developed accurate target-marking techniques to go with their precision attacks. Initially, they attacked using conventional bombs, but later they were the first squadron to use the 12,000 lb “Tallboy” bomb, another of Barnes Wallis’s designs, which had to be accurately delivered on specific targets rather than being used in the area bombing of German cities. To achieve maximum accuracy the squadron was given the Stabilising Automatic Bomb Sight (SABS). They were the only squadron to use this sight in preference to the standard Mk. XIV bomb sight used throughout Bomber Command. Only one other squadron in Bomber Command (9 Sqn) was trained to drop the Tallboy bomb, and they frequently accompanied 617 on its operations. Later, when an up-scaled 22000-lb version of the Tallboy was developed (the Grand Slam), 617 was the only squadron to use this weapon, using highly modified Lancaster aircraft to carry it. Before using these weapons, the squadron moved again to nearby Woodhall Spa in January 1944, and they remained there for the rest of WWII.