What is the meaning of righting lever?

Righting lever (GZ) is defined as the horizontal distance, measured in metres, between the centre of gravity (G) and the vertical line of action of the buoyancy force (Bf) acting through the centre of buoyancy (B1) when the ship is heeled.

What is righting moment in ship?

The Righting Moment is the best measure of a ship’s overall stability. It describes the ship’s true tendency to resist inclination and return to equilibrium. The Righting Moment is equal to the ship’s Righting Arm multiplied by the ship’s displacement.

How to find righting arm?

To determine GM from a righting-arm curve, draw a tangent to the curve at the origin, and a vertical line at 57.3° angle of heel. The height of the intersection of these two lines is the value of GM and may be read on the righting-arm scale.

What are righting arms?

[′rīd·iŋ ‚ärm] (naval architecture) The horizontal distance between the center of gravity and a vertical line through the center of buoyancy of a ship that is displaced from the upright position; knowledge of this quantity is necessary to determine the righting moment.

What is the maximum righting lever?

The righting lever (GZ) shall be at least 0.20 meters at an angle of heel equal to or greater than 30°. The maximum righting lever shall occur at an angle of heel not less than 30°. The initial transverse metacentric height shall not be less than 0.15 meters.

What is the maximum righting lever shall occur at an angle of heel?

The maximum righting lever shall occur at an angle of heel not less than 30°. The initial transverse metacentric height shall not be less than 0.15 meters.

What is righting moment in naval architecture?

The moment resulting in the uprighting of the ship to its original orientation is called Righting Moment. The lever that causes the righting of a ship is the separation between the vertical lines passing through G and B1. This is called the Righting Lever, and abbreviated as GZ (refer to the figure above).

How does Bilging affects the stability of the ship?

How stability is Affected. a) Bilging is said to occur when ingress of water takes place into the vessel from a point below the waterline, such that the water is free to flow in and out of the vessel.

What is heel angle?

Heel: Semi-permanent angle of inclination caused by external forces, such as high speed turns, beam winds, and seas.

How do you read a GZ curve?

The point where the GZ curve meets the horizontal axis (shown as ‘C’ in the figure), is called the point of vanishing stability, since righting lever becomes zero at this point. So, any heel beyond this angle would result in a condition of negative stability.