SPEED AT SEA.

Dominion, Volume 1, Issue 72, 18 December 1907, Page 6

SPEED AT SEA.

Tiiebe can hardly be two opinions with, regard to the desirability of shortening sea -voyages, whether transoceanic- or merely coastal. A quick passage is relished by people of every class. In the ferry service a most important saving of time is often effected by an acceleration of perhaps' only a few minutes in the actual time of running from port to port. A landsman feels "out of it" on > an oceanliner in spite of all a modern vessel has to offer him with its palatial saloons, its wireless telegraphy, its daily newspaper, etc., and, as a -rule) will welcome any , decrease in the length of his imprisonment. To a smaller degree the shipper and the consignee q.re interested in celerity of tiansport, .although 'with them low freights are eminently desirable. • The vagaries of the Smolensk and the Petersbourg in their pursuit of alleged contraband during the Eusso-Japanese War has taught us—if such a lesson were needed—of the necessity for us as a commercial nation to possess com-merce-protectors as swift as any vessels afloat. then, .as business men, as globe-trotters, or as citizens of the greatest Empire the world has ever Seen, we cannot but'rejoice at the recent notable advance that ■ lias 'been made in ocean-travel,: and, above all, that the huge Cunarders have brought back to Britain the Blue Riband of the Atlantic. A writer in the "Manchester Guardian" of a recent date discourses on the. speed question, .and, after premising that the steam-turbine is most efficient when running at a high speed, that a ship's propeller will not work efficiently at this speed, and that mechanical gearing is out oi the question owing to the magnitude of the power to be transmitted—he goes on to picture the 30-knot Lusitanias of the future as floating Electric Supply Stations with dynamos driven by high-speed steam-turbines. From these_ the current will be led to .slowrunning motors situated right aft-and driving propellers of ordinary type through the medium of short lengths of shifting. He states that vessel is actually in process of being equipped along these lines by a well-known firm of electrical engineers. One point of advantage in the suggested arrangement will be the' elimination of the possibility of the engine-room sta.fi misconstruing the signals of the navigating officer and vice versa, and the writer in the "Guardian" conceives a sort of keyboard arrangement of pushbuttons on the bridge by means of which starting, stopping, and reversal will be instantaneously effected. "Then," he says, "the eye that sees danger and the hand that averts disaster will bo controlled by one brain." 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 preceding it, and the vessel that can give the Mauretania 20 miles in a hundred and a beating will need to be heavily powered indeed, that is to say, she will have'to carry a very large quantity of fuel. The principal advantage of the turbine is that it can drive a propeller shaft with much less vibration than can a reciprocating engine, thus enabling lighter scantlings to be used , throughout the hull. It is also of less weight, occupies less space, and requires a smaller engine-room staff. On the other hand, the same boiler power is required—a fact of which the personnel of the Maheno and the Maori ure probably aware—and, since a large proportion of the total weight of the machinery lies in the stokehold, the percentage saving is far from startling. 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 Loonguna and the Marama will show. On their voyages from England the consumption in both these vessels worked out at from 1.6 to i.7 lbs. per I.H.P. per hour. Now, if the proposed system of electric transmission prove practicable the steam-engine, whether rotary or reciprocating, will be faced by two formidable rivals. The launch was announced recently on the Clyde of a vessel to be propelled by producer gas. She may not prove serviceable in other respects, but each I.H.P. she develops will entail the expenditure of less than lJJlbs. of coal similar to that .used

aboard the Mararaa and the Locmgana. Admitted that the producer and engine are heavier than the steam engine and boiler, the saving of this percentage in coal consumption would compensate for this in a couple of hours. She would also require far fewer men in the stokehold. But there is one competitor even more powerful than the producer gas plant, namely, the Diesel Engine. There are no stokers or coal-passers-on watch, just the engineers and a greaser or two. (The lubrication is automatic.) There are practically no pumps to be tended, the entire installation consisting of the engine with its oil-tanks and connecting pipes. This machine, undoubtedly the .most economical prime-mover in existence, expends per I.H.P. per hour less than half a pound of the crudest surface scrapings or petroleum refuse. 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 monopoly being' set up, the reverse is the case with petroleum, and this will probably prevent the general use of the Diesel Engine on 6uch a gigantic scale. Neither this, nor the gas-producer has been manufactured in comparatively large powers as 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 marine propulsion and in the manner in which these problems are being attacked: but it is to be feared that the 30-knot ocean fliers will have to bide the coming of a new form of hull of a vastly improved type of propeller, or of the discovery of a virgin oil-bearing region of large extent.