Which stability occurs when no righting arms are created as the boat is inclined?

Which stability occurs when no righting arms are created as the boat is inclined?

• A. Positive stability
• B. Neutral stability (Correct)
• C. Negative stability
• D. None

Answer: (B)

When a vessel is tilted, stability depends on the restoring moment generated by the separation between the forces of weight and buoyancy. The righting arm (GZ) is the horizontal distance between those force lines, and the moment is weight times GZ. If tilting produces a positive GZ, the buoyancy and weight create a turning moment that pushes the boat back toward upright—that’s positive stability. If tilting produces zero righting arm, there’s no turning moment in either direction at that initial tilt; the boat simply stays at the inclined position—that’s neutral stability. If tilting produces a negative GZ, the moment tends to increase the tilt, leading to instability—that’s negative stability. Here, no righting arms are created as the boat is inclined, so the situation corresponds to neutral stability (the metacenter coincides with the center of gravity, GM = 0).

When a vessel is tilted, stability depends on the restoring moment generated by the separation between the forces of weight and buoyancy. The righting arm (GZ) is the horizontal distance between those force lines, and the moment is weight times GZ.

If tilting produces a positive GZ, the buoyancy and weight create a turning moment that pushes the boat back toward upright—that’s positive stability. If tilting produces zero righting arm, there’s no turning moment in either direction at that initial tilt; the boat simply stays at the inclined position—that’s neutral stability. If tilting produces a negative GZ, the moment tends to increase the tilt, leading to instability—that’s negative stability.

Here, no righting arms are created as the boat is inclined, so the situation corresponds to neutral stability (the metacenter coincides with the center of gravity, GM = 0).