The axis about which a ship tilts through the waterline center is known as what?

• A. GM
• B. GZ
• C. LCF
• D. BM

Answer: (C)

The tilt (roll) of a ship occurs about a line that runs fore-and-aft through the waterline at the longitudinal center of flotation. The Longitudinal Center of Flotation is the point along the hull where the buoyant force is considered to act for small heel or trim motions; as the ship heels, the buoyancy shifts, and the axis about which the vessel rotates is effectively this line through the waterline at the LCF. So the axis of tilting through the waterline center is the Longitudinal Center of Flotation.