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x October, 1911 ALTERNATOR _THRUST _ 2 S000H.L. stem ier A.C. MOTOR tT TAE MARINE REVIEW BLOCK PROPELLER SHAFT (Ne ps eae _ \Ahel ( aie Pump WOON Ae Baa rth GOVERNOR, 1 a + ae CLA SHIP. (sree acer aaa PLAN, oe Fic. 3--GENERAL ARRANGEMENT oF 5,000-K. W. ALTERNATING CURRENT TuRRO- ELEectTRIC MACHINERY, PRoPoseD FoR UNitep States NAvaL COLLIERS plant consists of a vacuum condenser, three-throw air pumps and centrifugal pumps. with electric motor drives. The current is led to a three-phase motor, which is. keyed direct to the main propeller shaft, and is capable of developing 1,900 b. h. p. at a speed of about 84 r. p.m. The steam is gener- ated m two Scotch boilers, with How- den's forced draft and liquid fuel burn- ers. This installation costs and weighs less than the normal equipment. The coal- saving is over 10 tons per day. . The design of the ship itself presents many novel features not germane to the subject under review. This design was prepared by John Reid & Co., 17 Bat- tery place, New York. Oil Electric Tank Barge for Canadian Service. The illustrations (Figs. 1 and 2) show the application of the system to the propulsion of a 245-ft. Canadian canal type tank barge. The equipment consists of three sep- arate units of Diesel non-reversible oil engines, each capable of developing 200 shaft h. p., and directly connected to ar alternating-current generator. The currents from one or all of the units are respectively led to the separate wind- ings of a three-phase motor keyed to the main propelling shaft and operating a single slow-turning screw. The great advantage and economy of this system consists in being able to run at full power or at one-third power, using one or three engines at full-load economy at will, thus providing for an economical operation impossible with any other propulsive system. The fact that non-reversible oil engines are used, running under governor control, greatly simplifies the maintenance and opera- tion. The control is operated by a low- tension interlocking switch, operated by an ordinary engine room telegraph. stand located in the pilot house, so that the maneuvering of the vessel is at all times in the hands of the navigating officer. This equipment increases the cost of the ship about 10 per cent above the normal, but the carrying capacity is very largely increased. Marine Turbo-Electric Installation Proposed for U. S. Navy Colliers. The installation illustrated in Figs. 3 and 4 shows a marine turbo-electric installation submitted to the U. S. navy department for adoption in one of the four large colliers recently given out . to contract. It consists of a steam turbo-alternator of 5,000 kw. capacity with condensing plant; the current is led to two motors, one being keyed to each propeller shaft. The machinery is right aft in the ves- sel; the steam is generated by Scotch boilers. The vessels in which it is proposed to install this machinery are 525 ft. long, and will carry a dead weight of 12,500 tons of coal, at a speed of 14 knots at sea. Here again the cost, weight and economy are better than can be shown with the normal reciprocating- engine equipment. Log Rafts on the Pacific The steamship owners of the Pa- cific coast are uniting to force the government action regarding the large number of log rafts which are being towed down the Oregon and. Cali- 363 fornia coasts, and are rapidly becom- ing a source of great danger to ship- - ping. These monster rafts, contain- ing many millions of feet of piles and poles, are made up in the Columbia river section and are towed down the coast to San Francisco and Los Angeles. During the past two months six of these great masses of timber have broken away from the tugs which have been towing them and _ have broken, covering the surface of the ocean for many miles with large logs: which are a constant menace to navi- gation. The logs are almost com- pletely submerged and in many cases cannot be seen from the pilot house Fic. 4--Proposep ARRANGEMENT OF O Exectric Proputsion FOR LAKE STEAMER, 250 Fr. sy 42 Fr. 6 In. sy 19 Fr.