Turbine Steamers.—Turbinia.—King Edward.—Queen Alexandra.—The Queen.—The Emerald.
The latest development of the marine engine is the Marine Steam Turbine, the invention of the Hon. C. A. Parsons, F.R.S., brother of the present Earl of Rosse, and a son of the builder of the famous “Birr” telescope, the largest reflecting telescope ever built.
The first vessel ever fitted with the new type of engine was appropriately named the Turbinia. This vessel is only 100 feet long by 9 feet beam and of a total displacement of 44½ tons, but she is some ten knots faster than any boat afloat of the same dimensions. Although the weight of her main engines is only about 4 tons, and the total weight of machinery, screws, and shafting, tanks, etc., is only 22 tons, she develops the enormous power of 2,100 I.H.T., being almost 100 H.P. per ton of machinery.
Prof. Ewing, in April, 1895, made some trials of the Turbinia on the Tyne, the highest speed then recorded being 32·75 knots, but in June of the same year a speed of 34½ knots was obtained at Cowes.
Three turbines are used for driving the vessel—high pressure, intermediate and low pressure. Each turbine driving direct on to a separate propeller shaft. Reversing is obtained by means of one or more separate turbines connected to the same shafts as the propelling turbines and working in a vacuum when the boat is going ahead.
Several torpedo destroyers and three yachts have been fitted with Parsons’ turbine engines. The first mercantile vessel to be so fitted was the King Edward, built by Messrs. Denny Brothers, Dumbarton, in 1901.
On her trial trip she attained a speed of 20½ knots, and during her first season on the Firth of Clyde (1901) she sailed 12,116 knots in 79 days on a coal consumption of 1,429 tons, at an average speed of 18½ knots per hour. So satisfied were her owners with her, that they gave an order to the same builders and engineers for a somewhat larger vessel for the following season.
The new (1902) turbine steamer is the Queen Alexandra, a three-deck passenger steamer intended also for the Firth of Clyde passenger service. She is 270 feet long, by 32 feet beam, and depth 11 feet 6 inches. She has two funnels, but only one pole mast. Her main deck is completely covered in from the bow to aft of the engine room, and above the spar deck she carries a shade deck 100 feet in length, to which passengers have access, and under which shelter is provided in wet weather.
Like her sister vessel, the King Edward, the main engines of the Queen Alexandra consist of three separate turbines, each driving its own shaft, the centre turbine being high-pressure, and the two side turbines low-pressure. The velocity of the centre shaft is about 700, and of each of the side shafts 1,000 revolutions per minute. On account of the high velocity at which the shafts revolve it is necessary to increase the number of propellers driven, and the turbine steamers, therefore, have five small propellers each, one on the centre shaft, and two each on the outside shafts. On the builders’ trials the Queen Alexandra exceeded the speed of the King Edward by a knot and a quarter. Her actual speed was 21·63 knots, equal to about 25 miles per hour.
Two Channel steamers designed to carry passengers and mails, and to be fitted with Parsons’ marine steam turbine engines, are now (1903) being built on the Clyde by Messrs. Wm. Denny and Brothers.