FSM of liquid in tanks

Discussion in 'Stability' started by athvas, Mar 22, 2013.

  1. athvas
    Joined: Feb 2013
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    Location: india

    athvas Senior Member

    Could anyone explain me the below regulation. ? Intact Stability code 3.1

    .2. tanks with filling levels variable (e.g., consumable liquids such as fuel oil, diesel oil and fresh water, and also liquid cargo and water ballast during liquid transfer operations). Except as permitted in 3.1.5 and 3.1.6, the free surface correction should be the maximum value attainable between the filling limits envisaged for each tank, consistent with any operating instructions

    How to set fsm for tanks at various operation conditions ? 10%, 50% and 100% condition?
  2. TANSL
    Joined: Sep 2011
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    Location: Spain

    TANSL Senior Member

  3. jehardiman
    Joined: Aug 2004
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    Location: Port Orchard, Washington, USA

    jehardiman Senior Member

    When you develop your tank capacity curves, you should calculate your free surface for each capacity (1%, 5%, 10%, etc) along with all the other data. Just like the shift in buoyancy when calculating GM, the reduction in GM or RM is proportional to the shift in the CG of the fluid, which is proportional to the moment of inertia of the free surface (as long as you don't hit the top of the tank). So generally, for normal tanks, the maximum reduction in GM occurs when the tank is somewhere less than 50%, but really you should calculate it for all levels and take the maximum.
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