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hull structure will gradually be ef- fected as new and sound methods are evolved through research and study. The work undertaken during the year, which involved the building of turbine electric propelling equipmenis for six ships, turbine gear propelling equipments for four ships, and several highly interesting electric-auxiliary installations, is described in the fol- lowing text. Turbine Electric Drive Ships Five of the six practically duplicate ships of the combination passenger- cargo type built for the United Mail Steamship Co., a subsidiary of the United Fruit Co., were placed in serv- ice during the year. The sixth ves- sel, the Peren (ex-SrcoviA), is rapidly nearing completion and will be com- missioned in the spring of 1933. Three ships, namely, the TALAMANCA, CHIRI- QulI, and PrETEN, are products of the Newport News Shipbuilding & Dry Dock Co., and three ships, the ANTI- GUA, QuIRIGUA, and VeERAGUA, of the Quincy, Mass., plant of the Bethlehem Shipbuilding Corp. Ltd. The ships are specially designed to popularize tourist cruises in the Car- ribean and Central American coun- tries in conjunction with commercial purposes, such as the carriage of mail, general cargo and tropical fruits. The passenger accommodations are luxurious in their appointments and special care has been exercised to af- ford maximum comfort in both tropi- cal and northern latitudes. The holds of the vessel, with the exception of the small space devoted to the storage of mail and baggage, are given over to refrigerated cargo space for the car- riage of tropical fruits on northbound passages. Sixteen compartments are provided, two of which are equipped for below-freezing temperatures. Turbine electric propulsion was se- lected by the owners because of their previous knowledge of the drive, its adaptability to the service, and its proven low cost of upkeep. The trade routes, which call for operation at re- duced speeds between ports of call in southern latitudes, require an installa- tion of great flexibility and one hav- ing high economy over wide power- ing ranges. In considering the aver- age load factor and the percentage of time that one-half of the generating equipments could be closed down with their attendant auxiliaries, it was evi- dent that electric drive was excellent- ly fitted for the service. From a fur- ther consideration of the load factor, it was also apparent that the inclu- sion of extreme measures for further reducing the fuel consumption was not warranted when equated on the basis of capital charges and cost of upkeep. Each factor was weighed on its own economic merits and a com- bination of design elements chosen with respect to overall results. The main propelling equipment on each ship consists of two main tur- 20 bine generators, each rated 4200 kilo- watt, 3500 revolutions per minute, 3150 volts, 3 phase, unity power fac- tor; two propelling motors of the synchronous type, each rated 5250 horsepower, 125 revolutions per min- ute, and one main operating panel and control group. The turbines are of the General Electric impulse type with 14 stages, and are mounted di- rectly above their respective con- densers. The main generators and propelling motors are of the totally enclosed type with air cooler arrange- ment. This feature makes it possible to closely control the temperature of the windings and also prevents the deposit of dust or other foreign ma- terial on the windings. The auxiliary generating plant con- sists of three turbine-driven, direct current generators, each rated 500 kilowatts, 3 wire, 120/240 volts. Each set consists of a 4779 revolutions per minute, 5 stage condensing turbine driving a generator through a reduc- tion gear at 900 revolutions per min- ute. One condenser serves the three machines and provision is also made for exhausting into the main conden- ser at sea, thus permitting of the closing down of the auxiliary con- denser under normal steaming condi- tions. Below Deck Auxiliaries The below deck auxiliaries consist of 45 motor-driven applications in the engine and fire rooms, 22 motor-driven cargo cooling fans, and 23 fans for ventilating the hull and quarters. The above deck auxiliaries, consisting of capstans, anchor windlass, warping winch, boat winches, and _ cargo winches are also completely electrified. Motors of the enclosed ventilated type with automatic type of starters and wide field control by means of field regulation, are used almost entirely for below deck service. Motors of the totally -enclosed, waterproof type are used for above deck service. In reviewing the installations on these ships, it is difficult to foresee in just what direction future improve- ments could be made. Every possible measure has been applied to make these ships the gems in their class, and their already growing popularity predicts even greater success for the future. The transatlantic super liner NORMANDIE building for the French line was launched during the year and has been slated for commission- ing in 1934. She is both the largest and the highest powered passenger ship of all time, and also the first ship to exceed 1000 feet in length. The propelling equipment which is being furnished by Astholm of France, an affiliated company of the General Electric Co., consists of four turbine- driven alternators, and four propelling motors of the synchronous type hav- ing a normal total horsepower out- put of 160,000. The propelling motors MARINE REviEw—January, 1933 are the largest ever built for any type of service either ashore or afloat. The ship will naturally hold great, interest for many years to come. The S. S. SANTA Rosa, first of four sister ships to be completed by the Federal Shipbuilding & Dry Dock Co. for the Panama Mail fleet of the Grace line, sailed on her maiden voyage Nov. 26, 1932. The three remaining ships, the SANTA PAULA, SANTA LUCIA and SANTA ELENA, which were near- ing completion at the close of the year, have been scheduled for their maiden voyages in January, February and April of 1933, respectively. These ships, which are of the twin screw, combination, passenger-cargo type, are specially designed for operation be- tween the east and west coasts of the United States via the Panama canal, and intermediate points in Central America and West Indies. From the standpoint of co-ordinated and modern engineering practices, the main and auxiliary power plants are of the most advanced design and com- bine all of the elements which tend to produce a high overall efficiency, such as high pressure, high tempera- ture steam, complete auxiliary elec- trification and feed water heating by the series extraction method. Turbines, Double Reduction Gears The main propelling plant on each ship consists of two double reduction turbine gear sets of General Electric type, each rated 6000 horsepower nor- mal, and 6600 horsepower maximum, at a propeller speed of 95 to 98 revolutions per minute, respectively. The reversing elements which are in- corporated in each low pressure cas- ing are designed to deliver 80 per cent of normal ahead torque. The steam conditions at the turbine throt- tle are 375 pounds gage pressure and 300 degrees Fahr. superheat. The turbines are divided into a high pres- sure element, which revolves at 4509 revolutions per minute and a low pres- sure element, which revolves at 3500 revolutions per minute. The low pressure element of each unit is de- signed for the additional power ca- pacity required to drive a 500 kilo- watt direct current auxiliary genera- tor from an extension of the low speed pinion. Under normal steaming con- ditions and at speeds of from 70 to 100 per cent, these auxiliary genera- tors furnish all of the auxiliary power. Each unit delivers its power to a sepa- rate bus. A turbine-driven auxiliary generator of 500 kilowatt capacity acts as a Standby unit for each bus, and an au- tomatic change-over device is provided for shifting the load when the speed of the main unit drops below the pre- scribed 70 per cent speed. The stand- by sets are motored by their own gen- erators at about 95 per cent speed when acting as standbys and the tur- bines operated with closed throttle on vacuum. An additional turbine-