Chum - Speedy Inboard Runabout - By W. D. JACKSON. This convex bottom (hydroconic) runabout is 15 1/2 ft. long with a beam of 6 ft. and a maximum draft of 20 inches. You can use either a double cockpit or a single cockpit style for utility use. Chum was designed for use with a Marined Jeep Engine such as the Lehman Econ-O-Power, which develops 60 hp at 3400 rpm and will propel Chum at over 30 mph. Any 25-100 hp similar engine may also be used to power Chum, as long as the motor is of light weight, high speed design.