UTILITIES OF FREE RUNNING MODELS IN SHIP MANEUVERABILITY RESEARCHES (1), (2)

The present paper deals with a procedure of obtaining resistance derivatives from free-running model steering experiments. This is carried out by analysing "steering quality indices" produced from frequency response analysis upon the test results, but also using drift angle observed in circular turning and also estimating virtual mass and moment of inertia of a model from calculation or experiments. Thus free-model experiments may yield information not only for steering motion of a ship but for forces acting on her. Measurements of rudder force in circular turning may also be useful for getting information on the forces through total-less-rudder moment procedure of Davidson and Schiff and through the similar procedure for lateral force. Two new procedures of analysing the standard manoeuvre are also discussed and both are based upon the first-order equation of motion of integrated form of Eq.(5). The first of the two is to solve the simultaneous equations derived by applying the above equation for several particular instants during a test and the second utilizes the least square error method for the similar equations set up at a certain time interval. A brief description radio-control instruments and measuring techniques for free-model experiments is finally presented. An illustrated system utilizing a conventional toy aeroplane radio-control is easy to construct and is enough to carry out various types of steering experiments. A new device for precision measuring of heading angle using a free-gyro and photo-transistor detector is introduced, with a current meter measuring ship speed, a photographic means of obtaining drift angle and wire-strain-gauge type rudder forces measurement.

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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:
    • Nomoto, K
    • Murase, A
    • Tatano, H
  • Publication Date: 1961

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  • Accession Number: 00323672
  • Record Type: Publication
  • Source Agency: Stevens Institute of Technology
  • Report/Paper Numbers: Vols 109, 110
  • Files: TRIS
  • Created Date: Apr 15 1981 12:00AM