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decreased operating and maintenance costs and of greater cargo-carrying capacity on the same draft with the resultant benefit of greater profits. After several years study of the particular problems and proper ap- plication requirements associated with the propulsion of bulk freighters, and having in mind that reliability and continuity of operation are of first importance, we have worked up and give herewith a comparison between a geared-turbine unit, including conden- ser, which we believe to be the more reliable, and the large, heavy, cum- bersome, reciprocating engine now be- ing used in such ships. In order to have a fair comparison between the two types of drive, and to be absolutely certain that the two are placed on the same basis, we are tak- ing two exactly similar vessels as follows: Comparison of Standard Bulk Freight- ers. 90 RPM of Propeller: 1—2000 S.H.P. Geared 1—2200 I.H.P. Recipro- Turbine cating 2—Water-tube boilers 2—Scotch “pollers 2—Multiple retort un- 1—Surface condenser derfeed stokers with aux. 1—Surface condenser 1—Horseshoe thrust with aux. Water in boilers oki cane ry propeller Water in condenser thrust Lubricating oil Water in boilers Coal consumption Water in condenser per hour Lubricating oil Underway 8875 Coal consumption pounds in_ port per hour 817 Underway 2598 pounds in port i 817 Total coal for round trip from Conneaut, O., to Duluth, Minn., with no cargo upbound, tak- ing seven full days, or 150 hours under way at 2000 shaft horsepower of turbine, 2200 in- dicated horsepower of engine and 18 hours in port for either case: Total weight of the above main boilers, pro- pelling machinery, stokers, coal, lubricating oil, water in boilers, water in condensers, each case: 195 tons 298 tons 807,000 pounds 1,867,400 pounds All other engine room and deck auxiliaries same for each case. Net saving of machinery, water and fuel in vessel having water-tube boilers, stokers and geared-turbines is 560,400 pounds or 280.2 tons. This weight saving represents use- ful revenue-earning cargo which could be carried on each down-bound trip. | : aa J re i | anal pesehiars As | \7%8) i A | | | | 1 3 H ¢€ Condenser { I ( ' ' 1 ' 1 | i { SIZE OF 2000 SHR GEARED TURBINE 85 #.PM. AS COMPARED TO RECIPROCATING ENGINE, SAME POWER, SPEEQ AND SCALE Beat ® It should be noted in addition, that no credit has been given to the geared turbine ship for having foundations of considerably less weight, which it would have, as a result of its much smaller machinery weight. Now, based upon an average sea- son of seven months, and an average ship speed which would result in 30 round trips per season, we can make an analysis of the savings of the ship propelled by the geared-turbine, when compared with the one having reci- Spar Deck AT LEFT—PLAN AND ELEVATION OF STEAM TURBINE GEARED UNIT DESIGNED TO PROPEL GREAT LAKES FREIGHTERS. AT RIGHT—PLAN OF STANDARD ENGINE ROOM OF LAKE BULK FREIGHTER WITH GEARED TURBINE MACHINERY IN PLACE MARINE REVIEW—June, 1930 35