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324 masses of metal, instead of towering cylinders and columns inside of and about which piston and connecting rods, crossheads, valve motions, crank-shafts, levers, etc., are flying to and fro, it is self-evident that the old 'style must give way to the new. When it is borne in mind that it has taken over 70 years to render all parts of the re- ciprocating marine machinery fit for the work, it cannot be gainsaid but that THe MARINE REVIEW ply the turbine to slow-speed vessels by the adoption of multiple propellers, say three, (.as on moderate-speed liners. These propellers, smaler in, diameter than the present single or twin screws, running at such speed of revolution as would allow of direct connection to the Parsons turbine, could, in the author's opinion, be applied, and at but little if any more first cost than in existing practice; for although the cost of three Table I. ilers, Engines I Average Results. i. eh sas See, 1872 1881 8° 1891 1901 s90et Boiler pressure ib, per sq. in.....,..-.. 52.4 77.4 158.5 197 ae Heating surface per sq. ft. of grate sq.ft. .... 30.4 31 38 & 43 as rot Heating surface per Ii H. -PB.. sq. ft. 4.41 3.917 3.275 3.0 as 16 Godi per sq. it. of erate, lb.o4 oe a 13.8 15 18 & 28 as 1 ikevolutions per minute, revs. ..... 0... 55.67 59.76 63.75 87 ones Piston Speed ff, "Pere mill... .. 6. c.e% 376 467 529 654 None Coal per T, H.-P per- hour, ih. 3.) 2AF 1.83 152 1.48 as 1901 Average consumption on prolonged sea ; voyage, lb = Oe ae hac he ee i 2 1.75 1.55 *Natural and forced draught respectively. 1 Turbines. in a few years the difficulties yet to be experienced will be surmounted by the adoption of the turbine in the cargo steamer. Turbine Machinery for Cargo Vessels. In order to make some efforts to bring about the use of the steam-tur- bine or other form of rotary machin- ery in this type of vessel, it will not be out of place here to consider the nature of the problem which awaits solution. In full-lined vessels of the single-screw "tramp" type, the speed of revolutions of the propeller is not so great as to allow of the propeller- shaft being driven direct from the turbine-rotor, so that it seems as if even for this cass of vessels it would be necessary (notwithstanding the in- creased first cost) to adopt twin or ven triple screws. In view of the present depressed state of shipping, this seems rather a startling proposition, but as for all practical purposes it is bet- ter to have more than one propeller -on any vessel, there is no reason why, if a better type of propelling power 'ean be obtained, this should not be done in the same way as the departure was made from the two to three, four and five-crank engines in all classes of merchant vessels. It may be remembered that when these multiple cranks were first adopted, it was generally remarked by those who knew that multip'e cranks were all very well for high-speed mail boats, that three-crank engines. would not suit the cargo tramp; whereas, today they are fitted in all sorts, from trawl- ers, drifters, etc, and even five-crank engines are now found on cargo boats and six cranks on express liners, Bear- ing this in mind, there does not seem to be an insuperable objection to ap- lines of 'shafting is to be met, they would be much smaller and_ lighter, and the advantage of the boiler pres- sure being much lower would enab'e considerable saving of cost and weight to be gained. The marked advantages of turbine machinery in all the numerous vessels fitted up to date is so evident that it will be worth while enumerating them here, in order to point out the desira- bility of an early effort being made to apply them to the class of vessel now under consideration :-- (a) The rapid changes of motion (twice per revolution) being done away with, the risk and liability due to fractures or flaws caused by con- cussions and shocks is altogether elim- inated. (b) The absence of piston-rods, glands, side valves, guides, crossheads, connecting rods, link motion and crank shafts removes all risk of undue heat- ing and distortion of parts. (c) The steady revolving motion of the shafting reduces the risk of break- age of shafts and propeller-blades to a minimum, and also allows of less supervision, so that the men in charge can devote more time to the firing and working of boilers, etc. . (d) The avoidance of risk of seri- ous breakdowns caused by racing in heavy seas. (e) The marked economy brought about by the very great reduction in the use of consumable and other stores, such as oil, packing, etc. (f) The saving in opening and adjusting overhauling. men's and time in general (9) The avoidance of an extensive outfit of tools and gear necessary to effect the work. (4) The reduction in first cost of September, 1909 . many spare parts which must be car- ried for piston machinery in case of a breakdown. (i) The lowering of boiler pressure © which has alowed of an extensive re- duction in weight and first cost. (j) Aother advantage is that the past eight years have shown that the Parsons turbine machinery will not break down or stop. From extensive inquiries which the author has made, notwithstanding that there are now over 70 steamers continuously plying to and fro, no sailing schedules have been upset by a failure of machinery up to the present, nor has a turbine steam- er ever had to be towed into port, ~On the other hand, beyond the diff- culty of keeping down the speed of propeller revolutions to suit the tur- bine, the objections against its adop- tion" are not very serious; apparently some cargo space will be absorbed by having two or three tunnels aft, but this can be partly compensated for by a considerable reduction of engine- room opening through the decks up- ward. The risk of breakage of pro- peler blades will, no doubt, be put forward; but this all recent experi- ence has shown in reality is no greater than with the single propeller, By consideration of the foregoing facts, it will be seen that the only (but naturally the most important) feature, which has so far been against the use of turbines for cargo boats, is the mechanical one of relative speed of turbine-rotor and propeller, and_ it is much to be desired that some sim- ilar syndicate to that which initiated the start on the Clyde boats be formed fo. make a start with a cargo boat, say, of 2,000 to 3,000 tons deadweight, and 10 knots speed. It also is neces- sary for those now actualy engaged in the manufacture of turbine machin- ery to give the matter the most care- ful investigation, for the author, speak- ing with considerable knowledge and experience of reciprocating or piston machinery, has no hesitation in stating that rotary machinery must eventually replace the present system. Considering that under the British flag there are more than 6,000 steam- ers of the cargo type, it will be readily conceded that this is an immense op- ening for the mechanical engineers of the country to supply new machinery for even the existing steamers. If this be the case--and the author is strongly of opinion it is--there will be a revival of re-engining vessels, such as was experienced in the early seven- ties in the replacing of simp'e by compound machinery, with the differ- ence that it will not be necessary to re-boiler,