Which term describes the point through which the weight of the entire ship's structure and contained load acts vertically downward?

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

Answer: (A)

Weight acts vertically downward through a single point called the center of gravity. This point represents the average location of the ship’s mass, including hull, cargo, fuel, and equipment. As loading changes, the center of gravity moves, shifting how the weight’s line of action interacts with the hull and affecting stability.

The center of buoyancy is the point where the buoyant force acts upward, and it moves as the hull shifts in the water. The metacenter is a stability reference that helps determine whether the ship will right itself when it heels; it’s the point where the buoyant force’s line of action would intersect the vertical through the center of gravity for small tilts. The Plimsoll line marks a legal load limit, not a force location.

So the downward weight acts through the center of gravity.