SPEED AT SEA.

Timaru Herald, Volume XIIC, Issue 13491, 13 January 1908, Page 3

SPEED AT SEA.

A writer in the Guardian" of ji recent date discourses on tlio swnl question, anil. after premising that the .-team-turbine is most efficient when running at ;i high .-peed, that a ship's, pro-pi-ler will nut work efficiently at this speed, ami that mechanical gearing js out of the i|itcstioit owing to ihe magnitude of the power to lie transmitted—he goes on to picture the "10-knot l.tisitanias of the future as Moating Electric Supply Stations with dynamos driven liy high speed .-l?a,tn-turhines. From these the currents will lie led In slow running motors situate! riijlil aft anil driving pro|>vlleis of ordinny type through ihe medium of short lengths of shafting. He states that a .vessel is actually in process of being equipped along these lilies by a well-known fiim of electrical engineers. The steam-turbine is deservedly high in popular estimation just now. but it •must be remembered that speed is a matter of power and power a. matter of coal consumption. Each additional knot costs far more to gain than the one preceeding it. and the vessel that can give the Mauretauia 2? miles in a hundred and a. beating, will need to be heavily powered indeed, that is to say she will have to earn- a very large quantity of fuel. The principal advantage of the turbine is that, it can drive a propeller shaft with much lesv vibration than can a reciprocating engine, thus enabling lighter scantling to ba used throughout the hull. It is also nf less wiight, occupies less space. • and lequire- a smaller engine-room staff. On the other hand, the same boiler power is '.eijuirecl—a fact of which the personal of ihe Maheno and the iMoari are probablyaware. As regards economy in fuel, really the deciding factor in future increases of speed, the turbine can promise but little, as the performances of the Eoongana. and the M annua, will show. On their voyages from England the consumption in both these vessels worked out at from 1.6 to 1.7 lbs. per 1.H.1', per hour;

If the proposed system of electric transmission prove piacucal the steam-engine, wlictiicr rotary or reciprocating, wn bu faced by two formidable rivals. 'lhe launch was announced recently on the Clyu'e of a vessel 10 be propelled by piouucer gas. >"> he may not prove sen iccab.e in other,, lespeets, but each 1.11.1'. slie devciopes will entail the vxijemtiture ul less tlian I.2ibs ol coal sa-nialar to that used aboard the .Mamma, and the Looiigana. Admitted that the producer and vngine are heavier than the steam engine ami boiler, the saving ot this percentage in coal consumption would compensate lor this in a couple of hours. She would also require far fewer men in the stokehold.

iJut there is one competitor even more powerful than the producer gas plant, namely, the Diesel Engine. U'here are no stokers or eoal-passers-on watch, just the engineers ami a greaser or two. (ilie lubrication is automatic.) There are practically'no pumps to be tended, the entire insUtllation consisting of the engine with its oil-tanks and connecting 2 > U ,es - Ihis machine, undoubtedly tlie most econonical i>rime-mover in existance, expends per 1.H.1'. per hour less than half a, pound of the crudest surface scrapings of petroleum rv-fuse. By its use there will thus be

a saving of over 70 per cent in the weight of fuel to be carried. But while, owing to the world wide distribution of coal, there is no risk of an effective monolopy being set up, the reverse is the case with petroleum, and this will probably prevent tlie general use of the Diesel Engine on such a gigantic scale. Neither this nor the gas- producer has been manufactured in comparatively large powers yet. but it is only a year or two ago since the same might have been said about the steam) turbine. Nothing assists so much the development of a machine type as a. little success. A great change has undoubtedly taken place in recent years in the problems of mariue propulsion, and in the manner in .which these problems are being attacked; but it is to be feared that the 50-knot ocean fliers will have to bide the coming of -a new form of hull or a vastly improved type of propeller, or of the discovery of a- virgin oil-bearing region of large extent.—(''Dominion."!