Several late eighteenth and early nineteenth century English canals used 'tub' boats, capable of carrying from 5 to 10 tons, often used with primitive boat lifts or inclines. The Aire & Calder Navigation's engineer developed this idea into the 'Tom Puddings', a compartment boat system for carrying coal. Moved in trains of up to 30 compartment boats by steam tugs, they were lifted out of the water and then tipped by hydraulic machinery to empty their cargo into sea-going ships.