The locomotive-type boiler installed in "Bonnington" was in diameter and long. This was probably the largest boiler of this type ever to have been built in Canada up to that time. The capacity of boilers to generate steam was measured by the grate area, meaning the size of the fire-box or fuel burning part of the boiler, and the heating surface, which is the total area heated by the fire available to generate steam. In the case of "Bonnington" the grate area of the boiler was over and the heating surface was . The boiler consumed up to 3,800 pounds of fuel in an hour, which over the approximately from Arrowhead to Robson meant a fuel consumption of approximately 15 tons of coal. As with the boiler, the engines for Bonnington were also the largest ever built for a sternwheeler in Canada.