What does a positive metacentric height indicate about a vessel?

A positive metacentric height indicates that a vessel has a stable configuration. Specifically, it implies that the center of gravity is located below the metacenter, which is a critical point used to assess stability. When a vessel tilts due to external forces, the buoyancy force acts through the center of buoyancy, which shifts as the vessel leans. The metacenter is the point at which the upward buoyancy force can be assumed to act when the vessel is tilted.

If the metacentric height is positive, it means that the metacenter is positioned above the center of gravity. When the vessel is tilted, the restoring moment generated by buoyancy will arise, which helps to return the vessel to an upright position. This ability to self-correct after being heeled over indicates good stability, making the vessel much safer in rough conditions.

In contrast, a negative metacentric height would suggest instability, where the vessel may not return to an upright position after being tilted, increasing the risk of capsizing. Thus, having a positive metacentric height is a critical aspect of vessel design and stability.