🔍 Key Concepts

• Relationship between GM (metacentric height) and vessel tenderness/stiffness • How KG (height of center of gravity) affects GM • Meaning of a tender vessel in terms of roll period and initial stability

💭 Think About

• Ask yourself: does a tender vessel have quick, snappy rolls or slow, easy rolls? What does that say about its initial stability? • If two vessels are identical except for being more or less tender, what must be different in their vertical centers (G, M) rather than their hull form? • How would raising or lowering G change GM, and how would that change affect the vessel’s tenderness?

✅ Before You Answer

• Recall the formula that links GM, KM, and KG and think how changing KG affects GM • Connect tenderness with the size of GM (large or small?) and the resulting roll characteristics • Consider whether a more tender vessel will have a larger or smaller righting arm (GZ) at small angles of heel