Massachusetts Maritime Academy First Year Practice Test

Stability is about how a vessel behaves when it is tilted and, more importantly, its tendency to return to upright after a disturbance. When the ship heels, the buoyant force shifts and a righting or overturning moment is created. If the center of gravity sits below the metacenter, the buoyancy shift generates a restoring moment that tends to bring the vessel back upright; this restoring capability is governed by the metacentric height (the distance between the center of gravity and the metacenter). A positive GM means a restoring moment exists, so the ship tends to recover after small tilts; a larger GM generally means a stronger righting moment (though it also makes the initial motion feel stiffer). If GM is negative, the vessel becomes unstable and can capsize. That’s why the definition centers on returning upright after a disturbance and why metacentric height is the controlling factor. The other options describe speed maintenance, structural maintenance, or cargo handling rather than the ship’s response to a tilt, so they do not define stability.