THE MODERN STEAMSHIP

New Zealand Tablet, Volume XXXVI, Issue 16, 23 April 1908, Page 12

THE MODERN STEAMSHIP

WHAT THE TURBINE REALLY IS

Tfaere is one striking fact which has doubtless impressed itself on tine minds of those who have followed the extraordinary development of Atlantic liners during the last ten or twenty years (says am- English periodical).. Not only are we building floating leviathan® today which ' are nearly three times as heavy and almost 200 ft longer than the biggest Atlantic liner of ten or twelve years ago, but these mammoth .vessels attain a far greater speed than their smaller rivals.

When, in 1900, the Hamburg - American liner 1 Deutschland.,^ a vessel 660 ft in length, whose gross tonnage is 16-.500, earned for itself the distinction of befing the fastest steams-hip in the world by maintaining, a speed of 23£ knots per hour— which is equal to 27 males on land — someone said it was the last wotd in quicli: sea travelling. But, as everyone knows, the ' Lusitania,' the mammoth Cunarder, which is almost twice as heavy and 125 ft longer than the ' Deutschlaftd,' has proved that it was a bad prophecy by showing herself quit© capable of maintaining her contract speed of 25 knots (nearly 29 miles') an hour.

Even that, however, is not the ' Lusitania's ' limit; but it is quite sufficient for the Admiralty, who have subsidized her building, as well as that Of her sister ship, ' Mauretania,' both of which will be available as arm<ed cruisers or scouts if required by the Government.

The speed attained by the ' Lusitanfia,' and the 31 miles accomplished the other day by the ' Mauretania,' are not only a triumph for the Cun<ard~ line, but also a huge success for the Hon. O. A. Parsons, the famous engineer, who has developed the steam turMne to that degree of efficiency wKich has enabled these floatfltog cities to travel through the water at such a speed. Until the advent of the turbine, the shaft of a liner's propeller was always rotated by driving a piston backwards and forwards through a steam cylinder on the exact lines of the ordinary steam-engine. In the turbine we have a cylinder, but instead of the steam tt'rivinqr the pMton-rod, which in turn rotates the shaft of the propeller, it acts in a more direct manner ujnon a huge drum, fixed to the shaft. On the outside of this drum., and affixed to the inner surface of the cylinder in which it revolves, are, in the case of the 1 lAisitanfta,' 1,500,000 protecting hollow-faced ~ blades or vanes, the longest bei,n.g 22in ami l^in wide. The fixed blades on the cylinder are slanted slightly in an opposite direction to those which revolve with_ the drum. Between these two sets of blades the steam Is -sent with terrific force. The fixed blades, -acting as a sort of guide to the steam, pass it to the -blades on. the drum, and it is the millions of microscopic atoms of steam, whiohi fly like so many bullets against the_ sloping blades, which cause the drum to revolve. Thje * Lusitania,' being propelled by four turbine screws, has, of course, four turbine motors in her engine room, and 1 the combined push of all the blades amounts to the 68,000 horse-power whioh is necessary to drive the ship at -25 knots. The rotating mass in the en#ine-room wed&bJs 600 tons and revolves .at about 200 revolutions a mdnute. Everything depends upon the proper * set ' and inclination of the two blades, which;, if correctly placed, use up to tfie last ounce the energy of the steam in its passage through thetur-' bine.

Altogether 100 a tons of coal are burnt daily by the ' Lus-itania ' to obtain her 25-lmot speed, and the quantity of coal consumed on a tnip to Nfcw York would keep the fires of 3000 wop cinq men's houses going for a year. No fewer than 250 firemen and trimmers are required to stoke the 192 furnaces in the ship, while the brass and steel tubes on the boilers and condensers are 144 males in length' and- . weigh 600 tons. The adoption of the turbine mes,ns not only increased speed to the same boler-power, but also less cost of upkeep, a smaller engine-room staff, and a diminished bill for lubricants. Furthermore, there is none of that vibrating which is so irritating- to passengers on vessels driven in the ordinary way, while the smaller engine-room ensures more commodious quarters and promenade space. , - Mr. Parsons " first 'demonstrated ' the suitability of the turbirie for the propuMon of steamships by buildinc the 8 Turbana,'- a vessel 1 of the dimensions of a torpedoboat, which in - 1897 achieved the then unprecedented' speed of 32$ knots (nearly 38 miles) on a measured mile. A still more refcnarkable performance was that of tt« torpedo-boat, destroyer, the ' Viper,' which" with

turbine engines of about 10,000 horse-power, reached a speed of 35£ knots, or nearly 41 miles an hour. Even more remarkable, however, is the power claimed for a. turbine-engine invented by a Glasgow engineer, which, although little more than a^ foot in »duimr eter, is capable of developing 40 horse-power. It . Is said tii'at this invention will revolutionise turbine propulsion, and that^ a, speed hitherto unknown will be possible, although ooily two blades are used «,s against the many thousands an each, of tire new Cunarders. Another engineer, living, in Liverpool, has also invented an engine which he claims is better than the; turbine. The cost would be less, he says, the speed and power greater, while tihtere is. no part of the engine that could not be made in a small engine shop. .It needs the smallest amount, of packing and ail, and, astounding as it may seem, m its internal construction it has neither nut nor fcolt.