Overshot waterwheel, made in the 1800s

model of overshot waterwheel on wooden stand (Watt Collection no. 1813)

Model of an overshot waterwheel on a wooden stand. The engineer James Watt (1736-1819), worked on the design of the overshot wheel and this model is now part of the Motive Power Collection at the Science Museum, London. The wheel is fitted with a toothed iron ring from which the power was taken off at high speed without transmission through the axle. The over-shot wheel is regarded as the most efficient type of water-wheel, relying on gravity rather than the force of water hitting paddles, as is the case with an undershot wheel.