Although the Dambuster weapon is known, colloquially, as a ‘bouncing bomb’ it would be rather more accurate to describe it as an unconventional depth charge. Officially, it was the Vickers Type 464 and was given the codename ‘Upkeep’.
Designed by Barnes Wallis in 1942, a total of 120 ‘Upkeep’ weapons were manufactured by Vickers-Armstrong in February 1943. Of this total, 62 of them were inert practice examples filled with concrete, the remaining 58 being ‘live’ and explosive-filled.
The live weapons were used on only one raid, Operation ‘Chastise’, on 16/17 May 1943. ‘Upkeep’ was steelcased with a width of 60 inches and a diameter of 50 inches. The ‘Upkeep’ weapon had to be delivered at a speed of 240-250 mph and at a range of 400-500 yards from the target. Prior to release, the bomb was rotated backwards at 500rpm and then it skipped across the surface of the water in a series of ‘bounces’ before crashing into the dam walls where it would immediately sink.
Then, at a depth of 30ft, hydrostatic fuse pistols would automatically fire and detonate the explosive filling, comprising 6,000lb of Torpex. A back-up chemical delay fuse would operate in the event of failure of the hydrostatic pistols and, if the…
