AN ANALYSIS OF THE MANEUVERABILITY OF SHIPS ASSOCIATED WITH UNUSUAL CHARACTERISTICS UNDER STEERAGE

In this paper, the authors deal with the maneuverability of a ship which was reported to have shown an excessive yawing and rudder motion under automatic control. Results of the spiral test have also shown that the ship responds quite capriciously at small rudder angle; i.e. the ship sometimes switched direction of turn without any change of rudder angle, and in most cases, periodical yawing of about 90 seconds was superposed. The authors, having assumed these phenomena to be induced by unsteady hydrodynamic forces caused by separation of the boundary layer, conducted experimental investigations using a free running model as well as a restrained model. Flowline observations have also been conducted on an image model in a wind tunnel. Analysing results obtained, the authors proposed a hydrodynamic explanation of this unusual behavior of the ship that it must be caused by a combination of periodic change of hydrodynamic yawing moment and an abrupt change of yawing moment on the drift angle basis.

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  • Corporate Authors:

    Society of Naval Architects of Japan

    15-16, Toranomon, 1-chome, Minato-ku
    Tokyo,   Japan 

    Society of Naval Architects of Japan

    15-16, Toranomon, 1-chome, Minato-ku
    Tokyo,   Japan 
  • Authors:
    • Motora, S
    • TAKAGI, M
    • Kokumai, A
    • KATO, H
    • Koyama, T
  • Publication Date: 1970

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  • Accession Number: 00323663
  • Record Type: Publication
  • Source Agency: Stevens Institute of Technology
  • Files: TRIS
  • Created Date: Mar 12 1981 12:00AM