Discussion in 'Stability' started by JKKING, Jun 30, 2015.

    Joined: Apr 2012
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    Location: Singapore

    JKKING New Member


    Could somebody advise whether we should consider free surface moment of water in the recess while considering the effect of swamping as per the 6.5.3 a) of ISO-12217-Part 1. The regulation specifically asks to consider calm water and that is the reason for this doubt?

    As per regulation

    "Calculate the righting moment curve (N⋅m) for the boat in the loaded arrival condition in calm water using computer modelling which correctly represents (in calm water) the heel, heave and trim of the boat, and with water in the recess allowed to flow in or out over gunwales or comings according to the attitude of the boat in calm water, assuming that no flow through drains occurs. When the boat is upright, the recess shall be assumed to be filled to the following percentage of the capacity at the recess retention level defined in 3.5.9:"

    Thank you in advance

    Best Regards
  2. Alik
    Joined: Jul 2003
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    Location: Thailand

    Alik Senior Member

    We model this recess as tank of infinite height, and calculate this effect inside the software. Alternatively, You can use theoretical formulas from ship theory for free surface.

    ISO12217-1:2013 is not friendly for calculations due to its approaches aimed at testing rather than design/engineering.
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