We might continue almost indefinitely describing different types of ships, but will content ourselves with a reference to the fleet of Thames passenger steamers built in 1905 for the London County Council. Of the thirty vessels constructed for the Council, twenty had their boilers and engines from the Scotts' Works. Ten of the steamers, in which this machinery was fitted, were built on the Clyde by Messrs. Napier and Miller; six at Southampton, by Messrs. John I. Thornycroft and Company; and four at Greenwich, by Messrs. G. Rennie and Company. These vessels are 130 ft. long, and of very light draught--2 ft. 10 in. when loaded. An idea of their proportions is given by the engraving on Plate XXXIV., facing this page, showing one of the Clyde-built vessels ready to steam from Greenock to London.
The engines for all of these vessels are of the compound, diagonal, surface-condensing type, the two cylinders being 16 in. and 31 in. in diameter, with a stroke of 3 ft.
One set of engines is illustrated on Plate XXXV., adjoining page 85. They have forged steel guide columns, to bind the cylinders to the three entablature frames. The crank-shaft is a solid steel forging, 6-5/8 in. in diameter, coupled to the steel paddle-shafts by flexible couplings. The surface-condenser, cylindrical in form and constructed of light brass sheets, is placed below the guide bars close to the cylinders. The water-ends are of cast brass, arranged for double circulation of the water. The air-pump, of the trunk type, is driven by bell-crank levers off the low-pressure connecting-rod. Two independent feed-pumps are driven off the same crosshead.
The auxiliary machinery includes a circulating pump with auxiliary air-pump attached, a direct-acting feed and bilge pump, a fan and engine for the forced draught, and an electric engine and dynamo.
Each steamer has one cylindrical steam boiler, 9 ft. in diameter by 9 ft. 3 in. long. The working steam pressure is 110 lb. The boilers are also illustrated on Plate XXXV. The twenty sets of engines and boilers were completed in a remarkably short space of time.
These steamers were designed for a service speed of 12 statute miles per hour, and a trial speed of 13 miles per hour, or 11.285 knots. The best trial performances were attained by the _FitzAilwin_ and the _Turner_, both built on the Clyde; they attained a speed of 14.1 miles per hour, or 12-1/4 knots, with the engines making 69.8 revolutions per minute, and indicating 360 horse-power. This is nearly 1 sea mile per hour more than was required by the contract.