🔍 Key Concepts

• Metacentric height (GM) and what it says about initial stability • Relationship between stability and a vessel’s rolling period (how fast or slow she rolls) • Effect of raising the vertical center of gravity (KG) on overall stability

💭 Think About

• When you load weight high and raise KG, are you making the vessel more or less stiff (stable)? • Does a very stable, ‘stiff’ vessel roll quickly or slowly compared to a tender, less stable vessel? • Think about extreme cases: a barge with very strong stability vs. a top‑heavy yacht in a seaway—whose roll is snappier and whose is slow and lazy?

✅ Before You Answer

• Decide first: does raising the vertical center of gravity increase or decrease stability? • Then decide: does increasing stability make the roll period longer or shorter? • Match the choice that correctly pairs the direction of stability change with the direction of roll‑period change.