How does weight distribution affect GM (metacentric height)?

How does weight distribution affect GM (metacentric height)?

• A. It has no effect on GM.
• B. It increases GM when weight is low.
• C. Improper weight distribution that raises the center of gravity reduces GM and initial stability.
• D. GM is determined solely by hull shape and water density.

Answer: (C)

Metacentric height measures initial stability and is the distance between the center of gravity and the metacenter. The metacenter is determined by the hull shape and buoyancy forces, while the center of gravity moves with how weight is distributed in the vessel. When weight is placed higher, the center of gravity rises. Since the metacenter stays essentially fixed for a given hull and water density, raising G reduces GM. A smaller GM means a smaller initial righting moment, so the ship is less stable at small heels. Conversely, packing weight lower lowers G, which increases GM and improves initial stability. So, improper weight distribution that raises the center of gravity reduces GM and initial stability.

Metacentric height measures initial stability and is the distance between the center of gravity and the metacenter. The metacenter is determined by the hull shape and buoyancy forces, while the center of gravity moves with how weight is distributed in the vessel.

When weight is placed higher, the center of gravity rises. Since the metacenter stays essentially fixed for a given hull and water density, raising G reduces GM. A smaller GM means a smaller initial righting moment, so the ship is less stable at small heels. Conversely, packing weight lower lowers G, which increases GM and improves initial stability.

So, improper weight distribution that raises the center of gravity reduces GM and initial stability.