Elevation and plan of no 9 dredger from the journal 'Engineering', (June 1871). The dredger was built by W Simons & Co of Renfrew for the Clyde Navigation Trustees. The growth in shipping trade in the second half of the 19th century, together with the increasing size of ships themselves, led to a considerable demand for dredgers to improve acces to ports all over the world. The shipyard of W Simons & Co specialised in the design and construction of dredgers. The majority were what is known as bucket dredgers, which work by collecting material from the seabed in a series of scoops and deposit it on deck to be disposed of in deep water afterwards.
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