Which factor primarily reduces initial stability by raising the center of gravity?

Which factor primarily reduces initial stability by raising the center of gravity?

• A. Increasing the hull weight at low height.
• B. Using lighter cargo reduces GM.
• C. Increasing water depth.
• D. Improper weight distribution that raises the center of gravity reduces GM and initial stability.

Answer: (D)

Initial stability is controlled by the metacentric height, the distance between the center of gravity (G) and the metacenter (M). For small tilts, the righting moment is approximately GM times the sine of the heel angle, so the larger GM is, the stronger the vessel resists tipping. When the center of gravity is raised, GM decreases, weakening the righting arm and reducing initial stability. Improper weight distribution that places heavy items high on the vessel raises the center of gravity, which lowers GM and makes the ship less stable initially. Other scenarios either place weight lower (which lowers G, increasing GM and stability) or do not directly alter GM in the same way.

Initial stability is controlled by the metacentric height, the distance between the center of gravity (G) and the metacenter (M). For small tilts, the righting moment is approximately GM times the sine of the heel angle, so the larger GM is, the stronger the vessel resists tipping. When the center of gravity is raised, GM decreases, weakening the righting arm and reducing initial stability. Improper weight distribution that places heavy items high on the vessel raises the center of gravity, which lowers GM and makes the ship less stable initially. Other scenarios either place weight lower (which lowers G, increasing GM and stability) or do not directly alter GM in the same way.