Canal Steamer Boilers

Reader's Letters & Queries: NarrowBoat, Autumn 2014

The “primitive vertical boiler” in the last illustration in ‘Transport Workers Battalions’ (Summer 2014 NB), from its funnel and smokebox at the back, looks to be a ClarkeChapman boiler, a derivative of the Cochran boiler but with a flatter-domed top as compared to the Cochran’s hemispherical top. Both designs have the advantage of a large steam space; this makes them good at meeting sudden demands for high power, so they were extensively used as ‘donkey boilers’ in ships. They have a good output for their ‘footprint’, so were used in some later Clyde puffers, but their height made them less suitable for canal use. Though Charles Nelson’s steamers had Clarke-Chapmans, most FMC boats used Scotch boilers (President’s current Clyde boiler was made by Cochran’s). ClarkeChapman and Cochran boilers have the same basic design as Scotch/Clyde boilers – the combustion gases rise through a combustion chamber at the b…