To establish an economic balance between the expenses (including loss of revenue) incurred in dry-docking for routine maintenance of a ship's bottom and propeller, and the gains from the improved performance, is an old problem that does not easily lend itself to solutions which are conclusive or generally valid. The Author re-examines this problem and its attendant difficulties in some detail, and derives equations for determining the economically optimum interval between dry-dockings. Because the validity of the assumptions made in the interests of simplification will sometimes be doubtful, and become it is difficult to determine a ship's speed (to obtain data for the calculations) independently of weather conditions, there may be some problems in using these equations. However, such difficulties can be overcome if speed and fuel consumption are measured in good weather conditions (in particular, when the sea is calm). The measurements, which require little in the way of equipment and no special skill, should be done whenever a speed decrease or increase due to a change in the condition of the hull or propeller is suspected. Order from: BSRA as No. 47,192.

  • Corporate Authors:

    Rassegna delle Industrie del Mare

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


  • Italian

Media Info

  • Features: References;
  • Pagination: 7 p.
  • Serial:
    • Marina Italiana
    • Volume: 75
    • Issue Number: 1/2
    • Publisher: Rassegna delle Industrie del Mare

Subject/Index Terms

Filing Info

  • Accession Number: 00168336
  • Record Type: Publication
  • Source Agency: British Ship Research Association
  • Files: TRIS
  • Created Date: Feb 16 1978 12:00AM