THE ACME IN TURBINES

Dominion, Volume 7, Issue 1886, 21 October 1913, Page 8

THE ACME IN TURBINES

$ FOR LOCAL TRADE. THE N.Z. SHIPPING CD'S. CHARTER Tho announcement {says tho Christchurch "Press") that the steamer Cairnross has been c'hartercd by the New Zealand Shipping Company to load at Montreal for Melbourne, Sydney, and New Zealand ports, is of moro than ordinary interest. Tho Cairnross is the first British steamer fitted with geared turbines to .be built for cargo .carrying. Tho problem of utilising tho turbine engine in cargo and other steamers of comparatively slow speeds, is ono that lias been tho subject of careful consideration and of numerous experiments, tho most interesting of which was the fitting of the steamer Vespasian with geared turbines. It is well known that the turbine ongine attains its greatest efficiency and economy at high speeds; and that the propellers of steamers give tho best results at a comparatively low rate of revolution. The geared turbine system, it is claimed, combines both tiieso advantages, a high speed engine geared down to a slow speed shaft and propeller. Great interest was aroused in shipbuilding and marine engineering circles by the statement made at tho annual meeting of tho Cairn Lino of Steamships, Ltd., of Newcastle-on-Tvn-e, concerning the trials of the Cairnross. Launched on November 26 last at Sunderland, to tho order of, tho Cairn Line, tho Cairnross, unlike other turbmo steamers, has a single screw, propelled bv geared turbines. The turbines, which are of tho high-speed land typo, designed to run about 1.700 revolutions per minute, aro two in number, for ahead driving, and consist of a high pressure turbine on the starboard side, and a low pressure turbine on the port side, fitted in .series, an turbine being embodied in tho same casing with tho latter. The pinions and gear wheel ■are situated just abaft the turbines, and aro designed to reduce tho revolutions of the main shaft and tho propeller to 65 revolutions per minute when the turbines are running at full speed.' _ For tho purpose of comparison with tho Cairnross, another now vessel of exactly tho same dimensions, the Cairngowan, was tested at tho _ same time, both running side by side in tho Bristol Channel and tho English Channel for 36 hours. The Cairngowan is a duplicate of tho Cairnross, except that tho former is driven by a single screw, actuated by triple expansion reciprocating engines. Tho boiler power of the two ships is identical. Both wero trimmed to the same draught, bunker coalc wore supplied from tho same colliery, and tho ship's usual firemen wero employed on each vessel during tho trials, The weather conditions wero unsatisfactory, but both sots of machinery rar very well. The results proved hiphlj favourable to the Cairnross with hci geared turbines, an economy of 15 pei cent, in fnel .consumption over tho re ciprocating' engines of tho other shi[ being recorded for the notf type of en Bl The CftirnroM will leave Montreal oi November 20, and is duo at Vt ellmgtoi about February 15.