Bouncing bomb

Vickers Type 464
code name: Upkeep
"Upkeep" bouncing bomb at the Imperial War Museum Duxford
TypeConventional (depth charge)
Place of originUnited Kingdom
Service history
In service16–17 May 1943
(Operation Chastise)
Used byNo. 617 Squadron RAF
WarsWorld War II
Production history
DesignerBarnes Wallis
DesignedApril 1942
ManufacturerVickers-Armstrongs
ProducedFebruary 1943
No. built120 (62 inert and 58 HE filled)
19 used operationally
VariantsHighball spherical bouncing bomb, inert training bombs
Specifications
Mass9,250 lb (4,200 kg)
Length60 in (1.52 m)
Width50 in (1.27 m)

Muzzle velocity240–250 mph (390–400 km/h)
500 rpm back-spin
Effective firing range400–500 yd (370–460 m)
FillingTorpex
Filling weight6,600 lb (2,990 kg)
Detonation
mechanism
hydrostatic fuze (depth of 30 feet (9.1 m)) with backup chemical time fuze.

A bouncing bomb is a bomb designed to bounce to a target across water in a calculated manner to avoid obstacles such as torpedo nets, and to allow both the bomb's speed on arrival at the target and the timing of its detonation to be predetermined, in a similar fashion to a regular naval depth charge. The inventor of the first such bomb was the British engineer Barnes Wallis, whose "Upkeep" bouncing bomb was used in the RAF's Operation Chastise of May 1943 to bounce into German dams and explode underwater, with an effect similar to the underground detonation of the later Grand Slam and Tallboy earthquake bombs, both of which he also invented.