Contents
What will happen to GZ if the angle of heel increases?
7.2. The GZ-curve for large heel angles is highly non-linear. With larger heel, GZ increases to a maximum. At a heel angle larger than the maximum, there is a strong decrease of GZ to zero. Figure 7.17 shows a typical GZ-curve for a ship in still water.
What is the significance of Meta centric height?
If the metacentre is above the centre of gravity, buoyancy restores stability when the ship tilts. The stability increases with the distance between metacentre and centre of gravity, called the metacentric height. If the metacentre is below the centre of gravity, the boat is unstable, and a tilt results in capsizing.
In which case may metacentric height be considered an indication of a vessel’s stability?
The metacentric height (GM) is a measurement of the initial static stability of a floating body. It is calculated as the distance between the centre of gravity of a ship and its metacentre. A larger metacentric height implies greater initial stability against overturning.
What is angle of heel?
Angle of loll is the state of a ship that is unstable when upright (i.e. has a negative metacentric height) and therefore takes on an angle of heel to either port or starboard. When this occurs, the vessel goes to neutral equilibrium, and the angle of heel at which it happens is called angle of loll.
What is the maximum righting lever?
The righting lever GZ should be at least 0.20 m at an angle of heel equal to or greater than 30°. 5. The maximum righting arm should occur at an angle of heel preferably exceeding 30° but not less than 25°.
What is angle of downflooding?
Downflooding angle means the static angle from the intersection of the vessel’s centerline and the waterline in calm water to the first opening that cannot be closed weathertight and through which downflooding can occur.
How do you calculate metacentric height?
GM – Metacentric Height: This measurement is calculated by subtracting KG from KM (GM = KM – KG). GM is a measure of the ship’s initial stability.
What is a capsizing moment?
Capsizing or keeling over occurs when a boat or ship is turned on its side or it is upside down in the water. If a capsized vessel has enough flotation to prevent sinking, it may recover on its own in changing conditions or through mechanical work if it is not stable inverted.
What is angle of Contraflexure?
Angle of contraflexure – the angle of heel up to which the rate of increase of GZ with heel is increasing. Though the GZ may increase further, the rate of increase of GZ begins to decrease at this angle. The range of stability – where all GZ values are positive. The maximum GZ lever & the angle at which it occurs.