.Nevertheless the introduction of compound en gines (see STEAM NAVIGATION), with their econ omy of space and fuel, marks the real begin ning of steam yachting, and since that time steam yachts have had a wonderful development. The list of the New York Yacht Club alone shows 262 steamers, of which ten register about 1000 tons. W. K. Vanderbilt's Valiant is 332 feet long and registers 1823 tons. She is driven by triple-ex pansion engines and twin screws.
Because of their speed, steam yachts have come into use as transports carrying business men be tween their country homes and town. The swift steam launch has been developed for this pur pose. The Stiletto, built by the Berresho1N. was the first notable launch of this kind in America. Though but 86 feet long and in use for twenty years, she was able (1903) to make 18 knots an hour. The Miranda, built by Thornycroft (1872), though but 50 feet long, had a record of 19 land miles an hour, but steamers of that class have much more favor in America than in Europe.
The limit in this class was reached in the Arrow, designed by Charles D. :Mosher (1900). She is 139.33 feet long and displaces 66 tons, but her record, as given by her designer, is 40 knots. She is fitted with quadruple-expansion engines that take steam at a pressure of 400 pounds from water-tube boilers.
The New York Yacht Club's list for 1903 shows three yachts with turbine engines, all of British design, and there is a fourth, the Reso lution, that has turbines of American design. Because turbines occupy a relatively small space, cause no vibration, give greater speed with no greater consumption of coal, and require fewer repairs, they are sure to displace reciprocating engines on all kinds of steam yachts. Capt. N.
G. llerreshoff, however, who is undoubtedly an authority, states it as his opinion- that turbines will displace reciprocating engines in high-speed yachts only. See STEAM TURBINES: STEAM NAVI GATION.
A conspicuous feature of yacht races in 1903 was the fleet of launches propelled by motors that used products of petroleum in place of steam. There are two classes of these motors. In one class fluid naphtha is vaporized in a coiled-tube boiler by the heat of a naphtha flame, and the vapor drives a reciprocating engine. In another class the petroleum product is injected with a volume of air into an engine cylinder and there exploded, when the pressure of the gas drives the piston. Alcohol is used in place of naphtha in some motors.
Naphtha launches first became popular in 1886. Thousands have been set afloat since that date. The Adios, built by 11. S. Leighton, of Syracuse, in 1902, though but 55 feet long, was driven at a speed of 23 land miles an hour, by a motor of 120 horse power. In a race between naphtha launches, on the Seine, in 1903, the swiftest reached a speed of 22 knots. The Edithia, owned by John H. Hanan, is a cruiser 114.9 feet long, and she is driven by motors that aggregate 120 horse power.
Electric storage batteries have been used to furnish power for launches. In 1889 the Delta, an electric, 39 feet long, in use on the Thames, England, covered long stretches at more than five miles an hour by using the power stored in 44 cells. lluch better results can be obtained now, but the lack of stations for recharging the cells prevents a common use of them.