The high speed steam launch Buzz (length 50 feet, beam six feet six inches, draught forward 9 inches, aft 16 inches; trial speed 28.16 miles per hour) designed by C D Mosher of Amesbury, Massachusetts, was fitted with a 8-inch by 8-inch stroke twin cylinder inverted-vertical simple condensing marine engine operating with steam supplied by a marine locomotive boiler, 2 feet 8 inches in diameter, with 250 brass tubes, 5 feet long, and directly coupled to a propeller 32 inches in diameter by 5 feet pitch. The total weight of the complete engine was 703 pounds, and the weight of the entire power plant was 4,700 pounds. It had an indicted horsepower of 160. And, a weight/power ratio of 29 pounds per indicated horsepower; which was much less than any other boat built at that time. The horsepower per ton displacement was nearly three times greater than that developed by any other vessel afloat at the time.