🔍 Key Concepts

• Angle of loll and what it tells you about a vessel's stability • Difference between righting arm (GZ) and metacentric height (GM) • Relationship between GZ and GM at small vs. large angles of heel

💭 Think About

• Think about what it physically means when a ship is heeled over and just barely in neutral balance without wanting to return upright or heel further. What must the righting moment be at that exact condition? • At the angle of loll, is the ship in stable, neutral, or unstable equilibrium? How does that equilibrium type relate to the size and sign of the righting arm? • Consider a GZ curve: what happens to the righting arm where the curve crosses the horizontal axis?

✅ Before You Answer

• Be clear on the definition: Angle of loll = angle where a vessel with negative GM upright finds a new equilibrium at an angle of heel • Remember: Righting arm (GZ) is the horizontal distance between G (center of gravity) and B1 (shifted center of buoyancy) at a given heel angle • Visualize or sketch the GZ curve and check what the value of GZ is exactly at the angle where the vessel transitions between heeling one way and the other.