THE TRIUMPH OF THE TURBINE
In recent years the greatest revolutionary step in steamship construction has been the invention and development of the turbine engine, the mechanism of which has been described elsewhere. Since the day of the little Turbinia, whose speed astonished the nautical world, the limit for size and speed of ships has again been materially advanced, and no thinking person will venture to predict restricting limits without a modifying question mark.
At the beginning of the twentieth century a keen rivalry had developed between England and the Continent for supremacy in transatlantic traffic, America having dropped out of the race. The Germans in particular had produced fast boats, such as the Deutschland and Kaiser Wilhelm II, which for several years held the ocean record for speed. But meanwhile the turbine engine was being perfected in England, the land of its invention, and presently turbine "greyhounds" began crossing the ocean and menacing the records held by the boats equipped with the older type of engine.
The reciprocating marine engine, however, had been steadily improved, until it was a marvel in efficiency. Quadruple expansion engines driving twin-screws of a size and shape known to develop the greatest efficiency, for several years offered invincible competition to the new type of engine. There were new conditions to be met, new difficulties to be overcome.
A decisive test of the merits of the turbine engine was given in 1905, when the Cunard Company built two vessels, the Caronia and Carmania, of exactly the same size and shape, the Caronia having the highest type of quadruple expansion reciprocating engines, while the Carmania was equipped with turbine engines. Here was a fair test of efficiency between the two types. And the turbine boat proved herself the better of the two by developing more than a knot greater speed per hour.
Still the Carmania offered no serious competition in speed to several of the German flyers. But in 1908 two more turbine ships, the Lusitania and Mauretania began making regular transatlantic voyages, and quickly distanced all competitors.
In size as well as in speed these sister ships mark an epoch in navigation. Turbine engines take the place of the usual reciprocating type, acting on four propellers for going ahead, and two separate propellers for going astern. These engines develop 68,000 horse-power. Stated in this way these figures convey little idea of the power developed. But when we say that it would take a line of horses one hundred and twenty miles long hitched tandem to develop the power generated in the compact space of the Mauretania's engine room, some idea of the power is gained.
It is not the matter of power, size, or speed alone that makes the twentieth century passenger steamer so completely outclass her predecessors. It is really the matter of comfort and safety afforded the ocean travelers. Safety against sinking from injury to the hull was provided for by the introduction of watertight compartments half a century ago, as we have seen; and the size of the Great Eastern has been surpassed in only a few instances. But it is since the beginning of the present century that two revolutionary safety devices have been perfected—wireless telegraphy and the submarine signaling apparatus. The wireless apparatus has been described in another chapter, and as it is used almost as much on land as at sea, cannot be considered as solely a nautical appliance. But the submarine signaling device, which is dependent upon water for transmission, is essentially a nautical mechanism.