USCG Stability Practice Test

A negative righting arm indicates that the forces acting on a vessel are such that it is not able to return to an upright position after being tilted. The righting arm is the horizontal distance between the center of gravity and the center of buoyancy when the vessel is heeled over. When this distance is positive, the vessel has a tendency to right itself; however, a negative righting arm implies that the center of gravity is higher than the center of buoyancy when the ship is tilted, creating a situation where the vessel becomes more heeled over rather than upright.

In practical terms, this negative righting arm signifies that any heeling motion will cause the vessel to lean further over, ultimately leading to instability and a potential capsize. Therefore, understanding that a negative righting arm corresponds to an unstable condition is crucial for assessing a vessel’s stability in different loading and sea conditions.