🔍 Key Concepts

• center of gravity (G) and how it moves as weight shifts • center of buoyancy (B) as the geometric center of the underwater volume of the vessel • the basic definition of initial stability and righting moments

💭 Think About

• Ask yourself: when a vessel heels, which point actually moves because the underwater shape changes, and which point moves because weights shift? • Think about what two points form the righting lever (GZ) in most stability diagrams you’ve seen in textbooks. • Which of the listed points is directly tied to the underwater volume of displacement rather than to the hull geometry or draft marks?

✅ Before You Answer

• Identify which option represents the center of the underwater volume of the displaced water. • Eliminate any options that are simply reference points for measurements and not true physical centers related to weight or buoyancy. • Confirm which pair of points (with G) is used to define the righting arm and metacentric height (GM) in basic stability theory.