Which term describes the point at which buoyant forces are considered to act upward for small heel angles?

• A. Center of Buoyancy
• B. Center of Gravity
• C. Metacenter
• D. Plimsoll

Answer: (A)

The buoyant force acts upward through the center of buoyancy—the centroid of the submerged volume. As the hull heels, the submerged shape changes, so the center of buoyancy shifts accordingly. But the immediate upward thrust always acts through that center of buoyancy, which is distinct from the center of gravity (where the weight acts downward) and from the metacenter (a point used to analyze stability as the ship tilts). The Plimsoll mark is simply a load-line reference and not related to buoyant force.