The Author describes a study of the coupled motions of yaw, sway, roll, and rudder of high-speed naval ships such as destroyers. The purpose of the study was to develop mathematical equations to represent the realistic manoeuvring behaviour of these ships, and then to examine, through a series of digital simulation runs, the yawing and rolling motions of the ships during high-speed operation. On the basis of recent captive-model tests on a high-speed ship form, important coupling effects between yaw, sway, roll, and rudder motions were included in the mathematical model. It is concluded inter alia that asymmetry of the underwater hull, due to rolling, generates yaw moment, with a consequent tendency to turn towards one direction (e.g., to port) when the ship is heeled the other way (i.e., to starboard), so contributing to inherent yaw instability due to roll combined with other coupling terms. When GM is small, the coupling terms can introduce severe rolling motions in a seaway, and the possibility exists of yaw/roll instability for a ship system with autopilot during high-speed operations. Refinement of autopilot characteristics has important effects on yawing and rolling behaviour. Series rolling problems frequently observed at high-ship-speeds in waves can be partly due to inherent yaw/roll instability or marginal stability.

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  • Corporate Authors:

    Pergamon Press, Incorporated

    Maxwell House, Fairview Park
    Elmsford, NY  United States  10523
  • Authors:
    • Eda, H
  • Publication Date: 1980

Media Info

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Filing Info

  • Accession Number: 00323271
  • Record Type: Publication
  • Source Agency: British Ship Research Association
  • Files: TRIS
  • Created Date: Feb 18 1981 12:00AM