Photograph showing a spokeshaving acros the edges of a sheave. A sheave is an integral part of a pulley block used in the management of the sails of ships. The development of the pulley block was fundamental to the workings of a ship as it meant heavier loads could be carried with les power. Increasing the number of pulleys increased the weight that could be moved. With the introduction of the Portsmouth block-making machinery in the early 19th century ship's pulley blocks no longer had to be made by hand. The machinery was designed by Marc Isambard Brunel (1769- 1849) and made by Henry Maudslay (1771-1831).
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