FUEL ECONOMY, PROPULSION EFFICIENCY, AND DIESEL ENGINE INSTALLATIONS

The Author, of Delft University of Technology, first briefly discusses alternative sources of energy (wind-coal, oil, and nuclear energy) for merchant ship propulsion. For the time being, at least, the fuel problem is centered on the use of oil of increased cost and lower quality, and the Author considers this problem in a detailed review of alternative types of power plants, with particular reference to low-speed Diesel installations and the economics of their operation. Among the aspects considered are propeller rpm and its influence on propeller efficiency, propeller diameter (which is strongly dependent on ship type), long-stroke low-speed engines, "faster" low-speed (e.g., 250 rpm) engines, and stern form. Economic comparisons are made between low-speed Diesel installations with (i) direct drive with one engine, (ii) indirect drive with one engine, and (iii) indirect drive with two engines, and a number of conclusions are drawn on fuel savings and other matters. It would seem to be profitable to lower the propeller rpm below 112 for the 10,000-12,000 hp range, and below 90 rpm for the 16,000-18,000 hp range, provided that a 9-m or 10.5-m diameter propeller, respectively, can be accommodated and a reduction gear is acceptable. Data are given in support of this view, with POP (Pay-Out Period) and IRR (Internal Rate of Return) as criteria. The analysis described is approximate, and some improvements are suggested. A general conclusion is the two-stroke engine, with indirect drive and propeller speed in the 50-60 rpm range, is technically feasible and economically attractive provided that the propeller diameter can be accommodated. A proposal of the Author's is mentioned in which the propeller penetrates the base line. Special reduction gears and shaft bearings would be required, and special devices would protect the propeller in docking or grounding; patents have been applied for. If a ship calls only occasionally at ports of restricted depth, the owner should consider whether it is economic to penalise propulsive efficiency for the rest of the time.

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  • Corporate Authors:

    IPC Industrial Press Limited

    Quadrant House, The Quadrant
    Sutton, Surrey,   England 
  • Authors:
    • Gallin, C
  • Publication Date: 1980-9

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Filing Info

  • Accession Number: 00329909
  • Record Type: Publication
  • Source Agency: British Ship Research Association
  • Files: TRIS
  • Created Date: Mar 12 1981 12:00AM