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ACHINERY for Cutters Algonquin, that geared turbines have been applied to such vessels as tug boats, patrol boats and salvage boats. The first tug boat to use such pro- pelling equipment was the Harry B. WILLIAMS, built in 1931 by the Manitowoc Shipbuilding Corp., for the Great Lakes Dredge & Dock Co. The geared turbine unit for this ves- sel was designed and built by the Westinghouse Electric & Mfg. Co; and was to a certain extent, based upon the very satisfactory results of somewhat similar equipments built by this company, during the war, for submarine chasers. The units which were installed in the cutters ALGONQUIN, COMANCHE and MonAwk built for the United States coast guard service at the yards of the Pusey & Jones Corp., Wilming- ton, Del., embody all the experience gained in the design, construction and eperation of the previous propelling units of this type. A few of the out- standing advantages of this prime mover will be considered in this article. The unit is self-contained in that the turbines, pinions and gears are supported by the gear case, thus per- mitting a very simple foundation. Any effect of misalignment caused by distortion of the ship is eliminated, except, of course, in the case of the low speed gear shaft which, in such case, is alone affected. By this arrangement a compact construction, requiring minimum space and having minimum weight is possible. In spite of the compact arrangement, the unit is very acces- sible. The pinions are short and stiff and are of ample size to take care of the inertia effect caused by quick starting and stopping. Bearing load- ings and stresses are symmetrically distributed. In fact one of the gov- erning factors in designing this unit was to make it capable of success- fully withstanding any abuse result- [ IS only within the last few years The author, Harold Anderson, is a member of the Marine Engineering De- partment, Westinghouse Electric & Mfg. Co., South Philadelphia Works. For a complete illustrated description of these new Coast Guard cutters and sister ves- sels the reader is referred to the October, 1934, issue. Results of standardization trials of the ONONDAGA and the ALGoN- QUIN will be found in the November and December, 1934, issues, respectively. 16 4 AIN pro- pelling tur- bine of impulse type, with double reduc- tion gearing, used im the single screw Coast Guard cutters Algon- quin, Comanche and Mohawk. Full power ahead, 1500 S.H. P. at 140 R.P.M. Astern turbine designed to de- velop 1500 S.H. P. at increased steam rate ® ing from cold starting and rapid and severe maneuvering. The condenser is mounted trans- versely, and the exhaust trunks are bolted directly to the turbines with- out expansion joints. Expansion is taken care of by mounting the con- denser on transverse vertical plates, which provide a sufficient amount of flexibility. A propeller type circulating pump is built into the lower part of the inlet water chamber and its turbine drive is mounted on top of this cham- ber. This construction requires no foundation for the pump and saves an appreciable amount of floor space. Main Propelling Turbine A special design of impulse turbine is used, consisting of four wheels, one of these wheels being mounted on the extended end of each high speed pinion shaft. The ahead turbine con- sists of a two-row wheel followed ly two single row wheels. Each wheel has a separate casing supported by the gear housing, and @ach casing is connected in series by cross over piping. The astern turbine consists of a single two-row wheel exhausting direct to the condenser. The ahead turbine is designed to develop 1500 shaft horsepower at 140 revolutions per minute when supplied with steam at 300 pounds MARINE REVIEwW—January, 1935 Comanche, Mohawk BY HAROLD ANDERSON 200 degrees gage, Fahr. superheat and 274% inches vacuum. A hand valve also permits efficient operation at 500 shaft horsepower and 100 revolutions per minute. The astern turbine is designed for 1500 shaft horsepower at an increased steam rate. All turbine cylinders are made of cast steel and are split to facilitate inspection and assembling. The lower half of each cylinder is bolted to the gear housing with a dowel fit. The nozzle chambers are cast integral with the cylinders and have the nozzles bolted on. The turbine blades are fastened by a tongue and groove arrangement and pins which are carefully fitted into reamed holes. Each blade is machined to form its own shroud and has a carefully machined shank at the other end to provide correct spac- ing. Where the shafts pass through the turbine casings, carbon glands are fitted. Each gland has three rings and steam at ten pounds gage pres- sure is used for sealing purposes. Main Reduction Gear The main reduction gear is of the steeple, double reduction type, hav- ing double helices with standard in- volute teeth. The entire gear train consists of two high speed pinions,