Floating Ship Equilibrium Conditions Quiz

Stable Equilibrium for a Floating Ship

• In a stable equilibrium, the center of gravity (G) is below the transverse metacentre (M)
• The Righting Moment ensures the ship returns to its original position after being disturbed, thereby maintaining stability
• The Righting Lever (GZ) is the distance between the center of gravity and the metacentre, and its significance lies in maintaining stability for a ship

Equilibrium Conditions

• Neutral equilibrium occurs when the center of gravity (G) and the transverse metacentre (M) are at the same height, making the ship unstable
• Neutral equilibrium is dangerous for a surface ship because it can easily capsize
• Unstable equilibrium occurs when the moment prevents the ship from righting
• The type of equilibrium condition that results in a moment that prevents the ship from righting is unstable equilibrium

Moments and Forces

• A bending moment is a type of moment of force that tends to bend a body about one of its fixed ends
• The concept of the center of gravity is used in physics to understand the balance and stability of objects
• The fundamental concept behind understanding the intact stability of a floating body is the center of gravity
• A twisting moment tends to rotate a body about a fulcrum
• The twisting moment affects a shaft by applying a torque that causes it to twist

Center of Gravity and Design

• The concept of the center of gravity is sometimes useful in designing static structures to ensure stability and balance
• When the vertical position of the center of gravity (G) is higher than the position of the transverse metacenter (M), the ship is unstable

Ship Stability and Capsizing

• A ship is considered unstable based on the parameter GM (metacentric height) if GM is less than or equal to zero
• If a ship's righting lever is negative when it heels to an angle, it will capsize
• For a ship to capsize, the center of gravity must be higher than the transverse metacentre, and the righting lever must be negative

Equilibrium Conditions and Torque

• The second condition of equilibrium for a body states that the sum of the clockwise moments must be equal to the sum of the counterclockwise moments
• Torque is defined in relation to equilibrium as the rotational force that causes an object to rotate or twist

Test your knowledge on stable equilibrium of floating ships by understanding the relation between the positions of the centre of gravity and centre of buoyancy. Explore how a ship achieves stable equilibrium when the vertical position of G is lower than the transverse metacentre (M).