THE FASTEST SHIP AFLOAT.

Auckland Star, Volume XXXI, Issue 213, 7 September 1900, Page 5

THE FASTEST SHIP AFLOAT.

For the time being- the honour of owning the fastest ship afloat belongs to England, and though it is within the pale of practical engineering to produce a still faster ship, H.M.s. Viper can certainly challenge the world for speed with the certainty that nothing can for a year or so stand much chance of "wiping' her eye." Last Friday the Viper, a turbine torpedo boat built for the Government at Wallsend-orr-Tyne, was given an unofficial series of trials in the North Sea, and twice in the course, of runs over the measured mile, made the extreme speed of 37.113 knots or 43 miles per hour. Her other runs were 35.503 knots, 36.585 knots?, and 3G.072 knots, and the mean for six runs was 3G.581 knots. And these figures were achieA'ed with a scratch crew of engineers—chiefly apprentices —her own engineers having, gone on strike. The Viper is 210 feet long, 21 feet beam, and has a draught of seA^en feet, and she carried a load of 380 tons when on trial. A rough idea of the principle of the steam turbine can be given thus: — Imagine a drum revolving inside a barrel and having a great number of small vanes set slantingty on its circumference, and imagine further that steam is admitted in one end of the barrel, and to find its way out at the other end has to rush past these vanes, acting upon them like the wind on the sails of a windmill. The steam is at a high pressure, and as it expands in its progress through the cylinder, so the vanes are enlarged to give it a greater surface on which to exert its diminishing force. A result of this system is to utilise a far greater proportion of the energy of the steam than is possible in other types of engine. As the turbine is a rotary engine it can be run at a very high rate of revolution. In the trials a mean of 1170 revolutions Avas registered, Avhile Avith the reciprocating engines visual in ships a speed of over 400 revolutions becomes injurious to the machine. The Viper has four turbines, driving*ahead, a high pressure, and a low pressure on each side. Each drives a separate shaft, and two propellers are mounted on each shaft, eight in all. Since a turbine cannot be. reversed separate motors have to be provided for .going astern. The Viper has two—one on each side. As a matter of fact, although, she travels 'backwards fast enough she cannot be steered, but this difficulty will doubtless be overcome. 1A few years hence Mr Parsons, who is the father of the, system of turbine propulsion for ships, expects to see the. turbine applied to the biggest vessels. So far his experiments have shoAvn that turbines are if anything- more efficient in direct ratio to the increase in their size. On the Viper trials they worked up to nearly 12.000 horse power, and Mr Parsons sees no reason why that cannot be indefinitely increased. He reckons, as compared Avitli thn old type of engine, turbines produce double the horse power in the same .space, and Aye save one-third of the weight. The absence of vibration, too. not only conduces to the comfort of the men, but adds to the life of the ship, for the severe strain caused by the vibration of reciprocating1 engines is largely responsible for the continual repairs which are necessary.