A decrease in the service speed of a ship to compensate for the high cost of fuel, or to offset other commercial difficulties, will result not only in reducing operating costs but also in reduced transport capacity and therefore reduced freight income. There is a simple relationship between cost savings and loss of freight, and a point is reached when these savings and losses are equal. The arithmetical calculation of these savings and losses is simple; the difficulty lies in establishing the consumption of fuel and lubricants for actual service conditions when speeds below the normal average service speed are employed, and this is a matter which has to be considered before the economic calculations can be made. The Author discusses the problem in detail, with particular reference to tankers and bulk carriers, under the headings: General; Considerations on Speeds and Corresponding Consumptions; Economic Balance; Numerical Examples; Analysis and Discussion of Numerical Results. The numerical results analysed refer to four ships of 250,000, 150,000, 90,000, and 50,000 tonnes nominal deadweight, operating between terminals 6,000, 8,000, and 12,000 miles apart, at speeds between their normal 16 knots and reduced speeds down to 10 knots, and including a number of graphs and tables in which data are presented for a number of different operating and economic conditions. Such an analysis should enable economic evaluations of voluntary speed-reductions to be made, particularly in the case of tankers. Order from BSRA as No. 48,034.

  • Corporate Authors:

    Rassegna delle Industrie del Mare

    Corso Andrea Podesta
    5A-20 Genoa,   Italy 
  • Authors:
    • Delbene, G
  • Publication Date: 1977


  • Italian

Media Info

  • Features: References;
  • Pagination: 10 p.
  • Serial:
    • Marina Italiana
    • Volume: 75
    • Issue Number: 7-8
    • Publisher: Rassegna delle Industrie del Mare

Subject/Index Terms

Filing Info

  • Accession Number: 00174222
  • Record Type: Publication
  • Source Agency: British Ship Research Association
  • Files: TRIS
  • Created Date: May 31 1978 12:00AM