🔍 Key Concepts

• Center of gravity (G) and how it moves when weight is added high vs low • Definition of GM (metacentric height) and its relation to initial stability • How righting moments depend on GM, displacement, and righting arm (GZ)

💭 Think About

• Visualize a simple box-shaped vessel: what happens to its balance if you stack weight higher and higher above its existing center of gravity? • If GM becomes larger, does the vessel feel "stiffer" or "tender" initially? Now think: does adding weight high make it feel more stiff or more tender? • Righting moment at small angles depends on GM; ask yourself: does raising the center of gravity increase or decrease that righting moment?

✅ Before You Answer

• Confirm how adding weight above G affects the vertical location of G (does G move up or down?). • Recall that GM = KM − KG; think about what happens to GM if KG increases because G rises. • For righting moments at small angles, verify the relationship: Righting Moment ≈ Displacement × GZ, and GZ ≈ GM × sin(heel angle) for small angles. What happens if GM gets smaller?