🔍 Key Concepts

• Righting arm (GZ) and how it is measured between the lines of action of buoyancy (B) and gravity (G) • How the center of gravity (G) can move in three directions: longitudinal, transverse, and vertical • Which movement of G actually changes the length of the righting lever when the ship heels

💭 Think About

• When a vessel heels, which shift of the center of gravity will most directly change the moment arm between buoyancy and gravity? • Think about which direction of G’s movement gets it closer to or farther from the metacenter (M) when the vessel is upright. • Of the three directions (fore‑and‑aft, side‑to‑side, up‑and‑down), which one is used when we talk about GM (metacentric height) and the size of the GZ curve?

✅ Before You Answer

• Be clear on the definitions of longitudinal, transverse, and vertical centers of gravity. • Recall that GM (metacentric height) is measured in which direction from G to M. • Verify which of the options is directly tied to the size of GZ and initial stability, not to trim or flooding limitations.