A steam launch (length 36 feet, beam 7 feet, draught 1 foot 6inches forward and 2 feet 6 inches aft; trial speed 9 miles per hour), fitted with two five and a half inch by five and a half inch stroke, 8 horsepower (total) marine engines, operating at 240 revolutions per minute with steam supplied at 60 pounds per square inch by a horizontal marine boiler, coupled to a two-bladed propeller 2 feet 6 inches in diameter; built by Messrs. Forrestt and Sons, Limehouse.