Steam Turbines
MARINE. The first vessel to be fitted with turbines was the "Turbinia." In 1897 she was equipped with turbines of the Parsons type, three engines being used, high pressure, intermediate and low. Each shaft was fitted with three propellers.
She attained the remarkable speed of 34½ knots per hour, and the results obtained in her trials were considered so successful that the adoption of turbines in other vessels very quickly followed.
In 1900 the British destroyer "Viper," turbine driven, made 36½ knots per hour. Passenger vessels, being built for convenience rather than speed, naturally did not make such a remarkable showing, but nevertheless, greater speeds were attained than had been found possible with the ordinary reciprocating engine. The first turbine driven passenger vessel was the "King Edward," which reached 201½ knots in 1901. The first transatlantic liners fitted with turbines were the "Victorian" and "Virginian," whose maximum speed reached / only 17 knots per hour. In 1907, however, the Cunard line built the "Lusitania" and the "Mauretania." These were quadruple screw turbines of 67,- 000 indicated horse power, equipped with two high pressure, two low pressure, and two reversing turbines. These vessels were capable of maintaining an average speed of 26 knots per hour.
In 1906, the British battleship "Dreadnought" was built and fitted with turbines, this being the first battleship to be so equipped. During her trials a STEAM WHISTLE speed of 21.25 knots was attained. Of recent years the number of vessels which have been equipped with turbines of improved pattern has been very great, the advantage of the turbine for marine work being now generally recognized.
The superiority of turbines over reciprocating engines is not solely due to the extra speed which can be attained. A turbine is lighter, of simpler construction, and more compact than a reciprocating engine. There is also much less vibration. At high speed there is a marked economy of fuel, but at low or moderate speed, the turbine consumes more coal than the reciprocating engine.
For general purposes, the turbine is proving more satisfactory than the reciprocating engine in nearly all cases where high speed is required. It is, however, of little use for low speeds, spe or in those cases where a heavy resistance has to be overcome when starting from rest. It is peculiarly adapted for driving dynamos. Its simpler construction is a strong point in its favor, its moving parts being much fewer than in the reciprocating engine. Moreover, the fact that the steam acts directly on the moving shaft without the intervention of pistons, connecting rods, etc., leads to greater efficiency. The comparatively late date at which it was developed for practical purposes is explained by the need for special steels and other alloys possessing the unusual strength and other properties required in engines of this type. In this connection, Kempe's "Engineer's Year Book" states, "A very important fact in the evolution of the steam turbine has been the introduction of the high grade steels now available, which alone have made the highest peripheral speeds now to be met with possible, and further developments may be expected to follow any reduction in the cost of finest steels."