For estimating the power requirement for a proposed new ship, there are three groups of methods to chose from: Type-Ship Methods, Statistical Methods, and Piecewise Methods. The piecewise methods are based on results of model tests, on theoretical considerations, and on the results of ship trials, and allow the special features of the proposal to receive better and more logical consideration than the other two groups. Moreover, piecewise methods have a broad area of application. The Author discusses this subject of power prediction under the following main headings, the piecewise method normally used at the Department of Ocean Engineering, Technical University of Denmark, being described in detail under headings (5) and (6): (1) Introduction. (2) Necessary Power. (3) Type-Ship Methods and Statistical Methods. (4) Essential Parameters for Prediction of Power. (5) Diagrams for Prediction of Power. (6) Piecewise Methods for Prediction of Power. (7) Ship Model Experiments. (8) Control (i.e. Checking) of Power Estimates. A number of power/deadweight curves (some of historic interest) and power/displacement curves, with ship-speed as parameter, are included for various types of ship. Several conclusions are drawn. For preliminary predictions of power for a given speed, simple statistical methods can often be used with good results; prediction based on a statistical method is very reliable if the proposed ship belongs to the relevant "standard family". The extra power, or service allowance, required fluctuates considerably, and depends to a great extent on the views of the shipowner. It is normally unnecessary to make model experiments for the preliminary prediction of the propulsion power required for merchant ships. Order from: BSRA as No. 47,495.

  • Corporate Authors:

    Royal Technical University of Denmark

    Department of Ocean Engineering
    2800 Lyngby,   Denmark 
  • Authors:
    • Harvald, S A
  • Publication Date: 1977-9

Media Info

  • Features: References;
  • Pagination: 50 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00170905
  • Record Type: Publication
  • Source Agency: British Ship Research Association
  • Files: TRIS
  • Created Date: Mar 29 1978 12:00AM