When buoyancy moves down, where does the metacenter move?

When buoyancy moves down, where does the metacenter move?

• A. Up
• B. Down
• C. Left
• D. Right

Answer: (A)

When assessing small-tilt stability, the metacenter is defined by where the buoyant force would act if the ship heels a tiny amount—essentially where the line of buoyancy intersects the vertical through the center of gravity. If the buoyancy line shifts downward as the hull sinks deeper, the geometry of the hull causes that intersection point to rise along the vertical. Therefore, the metacenter moves upward. This upward shift increases the metacentric height (GM) when the center of gravity stays in place, producing a restoring righting moment for small tilts.

When assessing small-tilt stability, the metacenter is defined by where the buoyant force would act if the ship heels a tiny amount—essentially where the line of buoyancy intersects the vertical through the center of gravity. If the buoyancy line shifts downward as the hull sinks deeper, the geometry of the hull causes that intersection point to rise along the vertical. Therefore, the metacenter moves upward. This upward shift increases the metacentric height (GM) when the center of gravity stays in place, producing a restoring righting moment for small tilts.