🔍 Key Concepts

• Free surface effect in partially filled tanks • Difference between stability problems and structural problems like hogging and sagging • Meaning of reserve buoyancy and when it is lost

💭 Think About

• Ask yourself: when a tank is only half full, what happens to the liquid inside if the ship rolls or heels? How does that affect stability? • Which of the options refers to a structural bending of the ship’s hull, and which refers to internal tank/liquid behavior? • Does having tanks half full immediately reduce the ship’s ability to float (reserve buoyancy), or mainly affect how stable/steady she is when inclined?

✅ Before You Answer

• Identify which choice is about liquid moving inside tanks rather than hull bending or flooding. • Eliminate options that describe longitudinal hull stress (bending along the length of the ship). • Confirm which phenomenon occurs in partially filled tanks and gets worse as the surface of the liquid can move freely.