During a routine voyage of the EXXON PHILADELPHIA (75,000 DWT) between Valdez, Alaska and San Francisco, a simple deceleration-acceleration maneuver was carried out during a time when the seas were calm and the wind negligible. Measurements of forward speed, heading angle, rudder angle and propeller RPM were made using ordinary ship instrumentation during the maneuver which took approximately thirty-five minutes, with the ship heading in the direction required by the voyage. System identification procedures and programs, developed at MIT, were used to analyze the ship's speed and propeller RPM measurements for the purpose of identifying (measuring) the resistance of the ship. In addition to successfully identifying the resistance coefficient, the wake fraction, thrust deduction factor and the propeller thrust of the actual ship were successfully identified. A comparison between predictions from the scaled model tests and ship trial measurements indicated significant scale effect in resistance, wake fraction and thrust deduction and small scale effect in propeller thrust.


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    Title :

    Measurement of Ship Resistance from Simple Trials during a Regular Voyage


    Contributors:

    Publication date :

    1988


    Size :

    53 pages


    Type of media :

    Report


    Type of material :

    No indication


    Language :

    English