A pulley block is a wooden housing used for the guiding of the ropes controlling the sails on a large ship. Very many were needed and they often were damaged at sea. They were made of several components but were ideal for mass production.

By 1806, forty-three steam-powered machines were in use, housed in the building known as Blockmills (1802). It was claimed that six men could now do the work previously done by 60. This revolutionary production line turned out 130,000 pulley blocks a year.

At Portsmouth Historic Dockyard, you can see some of the machinery in The Dockyard Apprentice Museum. In London, it can be seen in the Science Museum.

The design of the pulley block machinery and production line was the first of Marc Brunel's many initiatives to improve manufacturing techniques. There is some dispute whether Brunel alone should be credited with the design of the machinery or whether Maudslay should share the credit.

Machinery manufacture: Henry Maudslay