What term describes the sinking of the ship from an even keel to a near-even keel?

What term describes the sinking of the ship from an even keel to a near-even keel?

• A. Final descent
• B. Preliminary and secondary
• C. Neutral buoyancy
• D. Free surface effect

Answer: (B)

Free surface effect explains this sinking behavior. When tanks or compartments are only partially filled, the liquid inside has a free surface that can move as the ship heels or trims. As the hull settles from an upright position, the liquid shifts toward the low side, shifting the vessel’s center of gravity and reducing the metacentric height. That loss of stability makes the ship settle to a new equilibrium, often from an even keel toward a near-even keel. This is why management of ballast and filling levels is critical—free surface in partially filled tanks destabilizes the ship.

Free surface effect explains this sinking behavior. When tanks or compartments are only partially filled, the liquid inside has a free surface that can move as the ship heels or trims. As the hull settles from an upright position, the liquid shifts toward the low side, shifting the vessel’s center of gravity and reducing the metacentric height. That loss of stability makes the ship settle to a new equilibrium, often from an even keel toward a near-even keel. This is why management of ballast and filling levels is critical—free surface in partially filled tanks destabilizes the ship.