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Developments in Electricity for Marine Work During 1931 By W. E. Thau portant developments in marine propelling machinery took place in the United States, the most im- portant of which is the application of turbine electric drive in the two new Dollar line passenger ships, the PRESI- DENT COOLIDGE, and her sister ship the PRESIDENT Hoover. Other outstanding developments represented. are the geared turbine propelling equipment in the Ford canal boats, the CHESTER and the EpGrewatTrer, the geared tur- bine propelling equipment on _ the Great Lakes Dredge & Dock Co. tug boat, Harry B. WILLIAMS, and the gas- oline electric propelling equipment on the New York City fireboat, JoHN J. HARVEY. The Presmwent Coo.iper, built by the Newport News Shipbuilding & Dry Dock Co. for the Dollar Steam- ship lines, has an overall length of 654 feet 6 inches, a beam of 81 feet, a displacement of 31,000 tons and a designed sea speed of 20 knots. This “vessel is driven by Westinghouse twin screw turbine electric machinery de- signed for 26,500 shaft horsepower. Each generator is rated at 10,200 kilowatt, 4000 volts, 2660 revolutions per minute, and is of the three-phase, two pole type. The generator and tur- bine are carried on three bearings and supported by a foundation built into the ship. The turbines are of the combined impulse reaction type, equipped with a full hydraulic speed control gover: nor so arranged that all speed changes are effected remotely from the control station by means of a hydraulic relay. With one generator operating both motors, either motor may be operated slightly in either direction, and both motors may be operated together in the same or opposite directions. Thus, full maneuverability is available with either one of the two main turbine generators in operation. Although the machinery was speci- fied to develop a total of 26,500 horse- power at 134 revolutions per minute, the S. S. PresmpentT Cootince developed a total of 15,291 horsepower at 113 revolutions per minute for a period of four hours with one generator set without exceeding standardization al- lowable temperature rises and without abnormal stresses in the machinery. All auxiliaries except the feed pumps, lubricating oil pumps and D ‘rs the year 1931 some im- The author, W. E. Thau, is director of marine engineering, Westinghouse Elec- tric & Mfg. Co. 50 some miscellaneous service pumps are electrically driven. The first gasoline electric fireboat, the JOHN J. Harvey, built for the City of New York by the Todd Shipyard Corp., was placed in service in 1931. This boat is equipped with five 565 horsepower, 1150 revolutions per min- ute Sterling gasoline engines and Westinghouse’ generators. Two of these engines drive 340 kilowatt, 250 volt main generators and 29 kilowatt, 125 volt exciters. Two engines drive two 340 kilowatt generators and the fifth engine drives a double unit gen- erator consisting of two 170 kilowatt, 125 volt generators and a 29 kilowatt exciter. The vessel has twin screws, each driven by a Westinghouse 1065 horsepower, 625 volt, 425 revolutions per minute single unit motor. When going to a fire all five main engines furnish power for propulsion, giving a boat speed of slightly better than 17 miles per hour. When at the fire, the one main engine which drives the double unit generator furnishes power for propulsion, the double generator making it possible to get individual control on the propelling motors with the variable voltage system. The oth- er four main engines are connected to four fire pumps through magnetic clutches. In the field of diesel electric propul- sion, two vessels with this type of drive were completed in 1931 and the equipment for a third is being in- stalled. The first of these was the ferryboat SAN DiEGo, built for service in San Diego harbor. This ferry has three 225 kilowatt diesel generating sets and two 750 horsepower propul- sion motors, the vessel being of the double ended type. Diesel electric drive was used for the power yacht FriciA. The plant consists of two 270 kilowatt diesel driven generating sets furnishing power to two 330 horsepower 300 revo- lutions per minute propulsion motors. Complete electric auxiliary equip- ment was built for several of the new passenger vessels now being con- constructed, namely, the new Matson liner MARrreosA and two sister ships, and the United States lines transat- lantic liner, MANHATTAN, and her sis- tership. Each of these ships has four Westinghouse 500 kilowatt, 240/120 volt turbine driven direct current gen- erating sets. An interesting new development in the auxiliary field was the furnish- ing of electric equipment for a spe- MARINE REVIEW—February, 1932 cial trawling winch for the auxiliary ketch ATLANTIS. This vessel was built from funds of the Rockefeller Foundation for oceanographic work by the Woods Hole Oceanographic institu- tion. This winch is driven by a West- inghouse 70 horsepower motor and is equipped with special control with au- tomatic tension apparatus to prevent damage to the long cable, and to the specimen being obtained. An interesting installation was made on a diesel ferryboat for the Wilson line. This installation consisted of a Westinghouse 20 kilowatt, 535 to 1435 revolutions per minute, 125-volt auxil- iary generator which was belt driven from the direct connected diesel pro- pelling engine shaft. In the marine turbine field some in- genious developments have taken place in 1931: Multiple overhung wheel turbine drive, the 100 per cent astern power turbine drive, water box circulating pump and the lipless scoop circulator. The drive installed on the Ford canal boats CHESTER and EDGEWATER utilizes the Westinghouse multiple overhung wheel turbine arrangement. These vessels are twin screw type hav- ing a total horsepower of 1600. The turbines drive through double reduc- tion gears having two high speed pin- ions. There are four turbine casings to each gear. Each casing contains a single impulse wheel. Three wheels are used for ahead operation and one for astern operation. Another development of similar de- sign is found in the Great Lakes Dredge & Dock Co.’s tugboat Harry B. WILLIAMS. In this case also there are four Westinghouse turbine casings containing single wheels overhung on the pinions. Two wheels are used for ahead operation and two for astern operation. Thus the full 850 horse- power is available in each direction. A similar arrangement of machinery is used to drive the dredge pump on the dredge SINALOA owned and oper- ated by the Leatham Smith Dock Co. A very important development of the year is the Westinghouse lipless scoop and vertical, submerged, diver- gent discharge for condenser circula- tion. A quarter size model was built and tested on the destroyer WEL- BORNE C. Woop. The chief advantages of this type of scoop as compared with the conventional type of scoop are less weight, less space and practical elimination of injection and discharge piping. Except for a slight lip on the discharge, projections are eliminated, thus reducing the drag on the ship ap- proximately 50 per cent. Another installation of interest is the repowering of the propelling plants in the battleships PrNnNsyt- VANIA and ARIZONA, The high pres- sure, direct drive, inboard turbines were removed and geared units sub- stituted. New Westinghouse geared cruising turbines were installed on the outboard shafts.