Photograph showing a steam dredger manufactured by Lobnitz & Co at Renfrew, Scotland, at work in a harbour in Mexico. 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 access to ports all over the world. Material is excavated from the seabed, then deposited on deck or in barges alongside the dredger, to be disposed of afterwards, often in deeper water elsewhere. Lobnitz & Co's shipyards on Clydeside were one of the foremost builders of dredgers.
© Science Museum / Science & Society Picture Library