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September, 1909 In order to show how rapidly tur- bine machinery has come to the front, Figs. 1 and 2 have been compiled, and Number of Vessels from these it can be seen that the adoption of turbine machinery for marine propulsion has been extremely PLL LE 80 o 8 MERCHANT VESSELS. 1 : Built. Building. ae Tons 8 Wo. OF Vessels: EO es rag N 607300 BHR Fy masa ann | 4 6 8 8 Gross Tonnage......0...6... ) s : Vid ees ' T\ 40 8 = aN S is ' 4150+ t. % g : ms 8 4: S 20 3 Bs toe 2 < & od § le 1900 1903 1906 1909 |" : Year Foc: rapid, rising in the merchant service from one steamer and 3,500 horsepower in 1901 to 64 steamers and 603,200 horsepower in December, 1908. There is no doubt that the adoption will be- come increasingly rapid in the future, as the system spreads amongst all classes of steamers. Combined Piston and Turbine Machinery. An instance of the striving after improvements on the machinery of WARSHIPS OF ALL KINDS. Built. Building. No. of Vessels ----_ IHP of ,, @ ° o be Hundreds of Thousands -- NMumébcr of Vessels a 3° 1906 Year Ric: 2: steam vessels is illustrated by Fig. 3, which is an outline arrangement of the combined system of piston and turbine engines recent'y built by Messrs. Den- ny, of Dumbarton, for the direct New Zealand service. This was fitted on er named TAE. Marine REVIEW 3 the steamship Otaki, of the New Zea- land Shipping Co., London. The adop- tion of this combination has been brought about by the efficiency of the turbine system when working on the vacuum, as the terminal pressure in the low-pressure cylinder of either triple or quadruple machinery is as a. tule..so that: it: has been found that there is power enough remaining to drive another or third propeller before allowing the exhaust steam to reach the condenser, The opportunity of being able to ascertain what superiority may be in this arrangement over that of ordinary: piston engines was taken advantage of ee a high Looking Forward Leet 10 Ow 20. 80 oo Lee Oe | | 325 obtained; but it is evident that an ex- tensive adoption of this system will not be made, the days of the steam piston- engine for marine propulsion being numbered, Coming now to the mechanical details of turbine propulsion, it must be noted how few there are to discuss compared with the very numerous details of pis- ton engines, almost each one of which in itself has been the foundation of elaborate papers and discussion in the past. The only detail in the Parsons turbine-machine since the shape and formation of the blades in both the stator and rotor have been fixed by its inventor, is the fastening of the blades 40 30 Leet l Pic 23: by Messrs. Denny, who built one steam- the: Orart for the New Zealand Shipping Co., and on a sec- ond one being required they induced the owners to adopt the turbine com- bined system in. the second boat, both vessels having the same boiler power, The took and being built off the same lines. result of the trial trip, which place in October, 1908, showed a slight increase in speed of about half a knot over that of the Orari, and so far as can be ascertained this advantage has been maintained in the regular trade. As these twin vessels are like the Ca- ronia and Carmania, and also the Laurentic and Megantic, of special in- terest for comparative purposes, it may be of some service to note their particulars in Table II. So far as these combined piston and turbine-engined vessels have been at work, satisfactory results have been or vanes, and this is of such a simple nature that all difficu'ties have been surmounted, and so far as the turbine proper is concerned the wear and tear are trifling. No doubt in some cases trouble has been experienced in strain- ing in the rotors, due to centrifugal ac- tion, and it has been found that rapid corrosion in certain parts has taken place, but a few years' further experi- ence will probably solve and effectually remedy these and some other minor defects which have occurred. It is a pleasing duty to note how few are the details or defects now requiring attention in the turbines themselves, but it must not be forgotten that in the first trials many difficulties were ex- perienced, and special merit is due to those engaged in the early developing of this machinery, led by Mr. Parsons, for so ab'y and so practically overcom-