Intact Stability, Wind Overturning as per DNV GL

Discussion in 'Class Societies' started by mactavish, Feb 13, 2023.

  1. mactavish
    Joined: Sep 2014
    Posts: 19
    Likes: 1, Points: 3, Legacy Rep: 10
    Location: philippines

    mactavish Junior Member

    I would like to know what is the dynamic Angle that refers to this section

    From what i understand is i measure the area A (GZ area) and compare it with B (wind area). whenever the wind area meets the so called 40% of GZ Area curve that will be my dynamic angle?

    And it should be less than 2nd intercept and down flooding angle?

    Please see below picture for your reference.


    You are free to share your interpretation regarding this criteria.

    Fyi I have posted this as well on Stability category one might find it interesting so I posted it there.

    thank you and kind regards,
  2. jehardiman
    Joined: Aug 2004
    Posts: 3,597
    Likes: 974, Points: 113, Legacy Rep: 2040
    Location: Port Orchard, Washington, USA

    jehardiman Senior Member

    Basically what requirement is ensuring is that the available righting energy prior to capsize is greater than 40% of the energy required to overturn. What this does is provide excess energy to resist overturning moment generated by the instantaneous wave profile. It is important to remember that most well found and properly handled vessels are not capsized by the wind, but are rolled by the waves; and also that it is not wave height, but wave slope that makes combers dangerous.

    Edit to emphasize that 40% is the minimum, and the Dynamic Angle is the angle at which this occurs.
Forum posts represent the experience, opinion, and view of individual users. Boat Design Net does not necessarily endorse nor share the view of each individual post.
When making potentially dangerous or financial decisions, always employ and consult appropriate professionals. Your circumstances or experience may be different.