The Turbines of the New Cunarders.

Progress, Volume I, Issue 12, 1 October 1906, Page 341

The Turbines of the New Cunarders.

The most important feature of these vessels is the motive power. The installation of engines in a liner capable of developing some 80,000 horse power will be another triumph for British marine engineers. The powei will be divided into four units, each complete in itself, and each driving a separate propeller. By this disposition, even should one set of engines fail, there will still be available sufficient power to propel the vessel at some 22 knots per hour. Each unit will develop the same horse power. Owing to the great breadth of the ship the four turbines will be placed upon the same platform, and each will drive its separate shaft. The propellers of the inner pair of turbines will be placed just forward of the rudder m the position generally occupied, while the screws of the outer pair will be situated some little distance forward. The turbines will be of huge proportions. In the case of the Caroma, which is now plying between New York and Liverpool, and the machinery of which develops some 23,000 horse power, there are no fewer than 1,200,000 blades upon which the steam impinges. From this one gains some idea of the number required for these 80,000 horsepower engines. The turbine drums are some 12 It. in length by 8 ft. in diameter and weigh 15 tons. In the case of the rotors for the lowpressure turbines an interesting record m casting operations has been created by Sir W. G. Armstrong Whitworth and Company, at the Manchester works, by their fluid-pressure system. This was the casting of a steel ingot weighing 120 tons, the largest ever made. The ingot mould, which weighs 180 tons, was filled with molten steel and was then submitted to enormous pressure in a hydraulic press, the ram of which, some 6 ft. m diameter, was brought to bear upon the mass with a pressure of three tons per square inch. The molten mass was thus subjected to a total pressure of 12,000 tons. In casting such mammoth ingots cracks and fissures detrimental to the soundness of the metal are liable to develop, whereas by the fluid-pressure system the ingot is rendered perfectly homogeneous. Owing to the great beam of the ship it has been found possible to place the boilers four abreast and yet leave ample room for coal bunkers in the wings. The boilers are of the Scotch type and are of huge proportions, so that an adequate supply of steam can be raised in cases of emergency — if, for instance, the reserve power of the turbines were called into requisition in heavy weather.