This single column steam hammer was built in 1907, for the opening of the Clyde Port Authority (Clyde Navigation Trust) repair workshops in Renfrew. When the works closed the hammer was transferred, with other machinery, to the Scottish Maritime Museum. It is an example of a steam hammer made to Rigby’s patent by the leading maker of such machines, RG Ross & Sons at their Greenhead Engine Works in Glasgow. It was used to forge replacement parts for the Clyde Navigation Trusts’s fleet of dredgers and hopper barges. Steam hammes consists of a cast iron base plate and the hammer body which carries a steam piston and hammer head. It was operated by pulling on the long metal lever on the right hand side. This released steam into the piston making the hammer head move down with great force. A trained operator could vary the pressure the hammer head exerted - some chose to show off their skills by borrowing a watch, placing it under the hammer and halting the hammer head a fraction above the glass face.