The steam launch Eclipse (length 40 feet, beam 8 feet; trial speed eight and three quarters of a mile per hour) was fitted with a 6-inch by 5-inch stroke inverted-vertical simple marine engine operating at 300 revolutions per minute on steam supplied at 80 pounds per square inch by a marine return tubular boiler; built by Yarrow and Hedley, Poplar, for use on the Derwent at Hobart. The principal builders of steam launches at that time were Messrs. Yarrow and Hedley, Poplar, Messrs. Plenty, Newbury, Mr. Messenger, Ewell, and Messrs. Welsh and Berthson of Eden-Road.