The following text may have been generated by Optical Character Recognition, with varying degrees of accuracy. Reader beware!

8 MARINE REVIEW. Five Crank Type of Engines. A firm of English ship builders, Messrs. Wm. Gray & Co.of West Hartlepool, have fitted to a large cargo steamer, that is intended for long voyages in the trade to Australia and New Zealand, a set of five-crank engines. 'The vessel is named Inchmona. It is claimed that the five- crank system is the most suitable for large powers and for long-voyage boats, where economy of fuel is of great importance. The cost of machin- ery is increased, but the builders are claiming that this will be offset many times over by the saving in fuel. The engines are thus described by Fairplay of London: "There are two low-pressure cylinders of equal size, and the engines work on the quadruple principle, each of the five cylinders driving one of the five cranks. The cylinders are allin a straight line on the centre- line of the ship, and all the valves are on the same line, immediately over the crank shaft, and driven by the ordinary link-motion type of valve gear. The five cranks are set at equal angles around the crank circle, so that the propeller receives no less than ten impulses per revolution, be- sides which a much higher speed of revolution may be freely adopted than is usual with three-crank engines. A three-crank engine at sixty revolutions per minute, having six impulses per revolution, gives 360 im- pulses per minute; whilst a five-crank engine running eighty revolu- tions per minute, with ten impulses per revolution, will give the shaft 800 impulses per minute, or more than twice as many as the three-crank in temperature until on entering the boilers, it is nearly at the temperat- ure ofthe steam. On the trials of the engines atthe sheer-legs the thermometers registered about 400 degrees, Fahr., as the temperature of the feed-water as it passed the meter and entered the boilers. The five- crank system does not involve any great increase in length of engine room space, as the reduced diameters of cylinders allows the centres to be closer. In this ship the engine room is only one frame space longer than for the same power in three-crank engines." Turret Deck Freight Steamers. Twenty steamers of the turret deck type shown in the illustration on this page have been built by Wm. Doxford & Sons, Sunderland, England, The English firm began building steamers of this kind shortly after the American Steel Barge Co. was organized in this country, and they have met with unusual success among several firms of ship owners, who are satisfied that the turret deck steamer possesses many advantages over the ordinary freight carrier. Allof these steamers are large and of high power, and in two or three of them water tube boilers of Babcock & Wil- cox manufacture have been adopted. This English firm -also built, some time ago, from designs made by Capt. Alex. McDougall, a whale- back steamer for British owners. The steamer Selma, illustrated herewith, has a deadweight capacity of about 5,600 gross tons. She is owned by Geo. Horsely & Son of Har- STEAMER SELMA, LATEST OF THE TURRET-DECK TYPE, BUILT BY WM. DOXFORD & SONS, SUNDERLAND, ENG. engine. At the trials the engines ran so smoothly that at over 100 revo- lutions per minute there was no vibration of the ship whatever, although she was entirely without cargo. At this speed there are more than six- teen reciprocating impulses delivered per second. The high speed in the reversal of impulses accounts for the absence of vibration in the ship, the huge structure having no time to respond to the tendency that pro- _-duces vibration. With five cylinders, of which, as in the case of the Inchmona, the diameters are 17 inches, 24 inches, 34 inches, 42 inches and 42 inches, the three larger reciprocating weights can without difficulty be made exactly equal, and with alittle scheming the weights of the whole five can be made equal. The five-crank principle lends itself to the adoption of very high boiler pressures, which are considered insepar- able from a high degree of economy in coal consumption. In the case of the Inchmona the working pressure is 255 pounds per square inch, and the boilers, which are of the ordinary cylindrical multitubular type, were tested by Lloyd's to 510 pounds per square inch without any sign of leakage whatever. These boilers are fitted with Mudd's system of super- heating apparatus combined with the well known Ellis & Eaves type of induced draught, and with Serve tubes and retarders. An attem pt is here made not only to supply the engine with dry steam from the boilers, but toretain itina dry state throughout the engine; and to this effect there are combined with the superheater an apparatus that Mr. Mudd calls an initial receiver, an exceptionally complete system of steam jack- etting to the cylinders, and an exhaust control arrangement. There is also an unusually elaborate scheme of feed-heating. Instead of the usual single vessel, there are a series of feed-heaters worked at graduated temperatures, and as the water passes through these it continues to rise tlepool, and is the largest vessel of her type yet built. On a measured- mile trial she attained a speed of 10.6 knots. Her builders also turned out, a short time ago, a screw steamer of ordinary design that has a ca- pacity of 11,375 tons. This steamer is named Algoa. She is 465 feet long, 58 feet beam and 35 feet depth, and her load draft is 20 feet. Her engines are triple expansion, with cylinders 29, 50 and 80 inches diameter by 51 inches stroke. There are two large single-ended boilers fitted with Ellis & Eaves' induced draft and Serve tubes. May 1, 1898, is the time fixed for the completion of the subsidized ships that are to run between Canada and England. Now that advertise- ments calling for bids for the establishment of the line have been issued in England, it would seem that negotiations that have been pending for many months past are really to amount to something. The Canadian government offers a subsidy of $750,000, and it is expected that the British government will pay $375,000a year. The advertisement calls for a speed of 20 knots, which will necessitate the use of vessels capable of a max- imum speed of about 21% knots. They must have a displacement of 8,500 tons esch. They must have equipment equal to that of the Teu- tonic; accommodations for 275 first-class, 200 second class and 1,000 emigrant passengers, and suitable and sufficient cold storage rooms. In winter the vessel must land in Halifax, to leave the mails, but may then goon toSt. John, N. B. In summer they must leave the mails at Quebec, but then may go to Montreal. There are to be four vessels. Offers will be received until June 10. The service is to be weekly and for ten years. One dollar round trip excursion tickets between Cleveland and Lorain are on sale by agents of the Nickel Plate road. 78 July 31