ECONOMICAL SHIP

Hokitika Guardian, 1 February 1932, Page 2

ECONOMICAL SHIP

SMALL FUEL CONSUBIPTION. SBVEDE’S SIMPLE INVENTION. LONDON, December 7. Alongside . the Surrey Commercial Dock, unloading si cargo of timber, lies the Swedish s.s. Trione, a ship of 1600 tons gross and 2850 tons deadweight. This Swedish ship, similar to hundreds of other tramp .steamers, is, however, unusual in her engines, which combine in a way as simple as it is remarkable, the most ancient and modern marine engineering practice. Her engines are of the old triple expansion type, witli an -innovation, however, which may well 'restore the steam reciprocating engine to the supremacy it formerly held as the “draught-horse,” so as to speak, of the sea.

The invention of the Swedish engineer, Blr Bjorklung, is briefly as follows : The steam, after doing its work in the high-pressure cylinder, is passed through an electrical, super-heater before adniissou to the intermediate cylinder, so that it enters its second stage with a regenerated heat little short of tho 500 degrees superheat of the boiler steam. This “regeneration” results in a greatly inerensad efficiency, as subsequent figures will show. The ingenuity of the invention, however, is to be found in the economical means of obtaining this regenerative effect. As most laymen are aware, the steam, after doing its work in the low-pressure cylinder, is normally condensed and discharged overboard. In the Trione, on the other hand, this exhaust steam drives a low-power turbine, which generates the electricity that operates the regenerating super heater, the last ounce of work thus being derived from the steam or, in other words, from the fuel that raises the steam.

230 MILES ON 6} TONS. The ship has a normal speed of 9) knots at full load, a speed which can, of course, be exceeded if the vessel is pressed. At this speed the consumption of the- coal per h.p. has been reduced to the remarkably low figure of .941 b. per h.p. In non-technical terms this means that the Trione, on a guaranteed run, can do a day’s steaming of 230 miles on 6} tons of the best BVelsh coal. BB’hen it is appreciated that on saturated steam, with no super-heat in the boiler, between the Ist. and 2nd. expansion, the same vessel would require from 13 to 14 tons of coal, some idea of the value of this single invention can be obtained.

Not only is the exceptional efficiency of the engines reflected in fuel economy, but the .size and weight of the engines and are reduced, thus allowing extra weight and space for cargo,

The Trione is fitted with two Scotch boilers, and carries three firemen. Though the furnaces are hand-fired, one fireman only is required per watch in the stokehold, in which both bojb ers are situated. The air for the forced-draught is drawn from the top of the engine-room, and the heat of this air is an a'dded small factor in the efficiency of the propelling plant,

It will thus be seen that ancient' and modern practice meet ideally in this Swedish vessel, the only ship of her type in the world, She haß been visited by engineers of all nationalities while lying in the London Docks, and on her many extensive voyages she has fully justified her inventor’s claims.