🔍 Key Concepts

• Center of gravity (G) and the distance KG (height of G above a reference) • Common naval-architecture symbols for displacement (Δ), keel/baseline, and center of buoyancy (B) • Which point on a ship’s cross‑section is normally taken as the zero height for vertical measurements

💭 Think About

• Look at each symbol and recall which one represents the baseline/keel in stability diagrams and hydrostatic curves. • Ask yourself: KG is “height of G above what?” On a typical stability problem, from which point do you start measuring vertical distances? • Which of the shown symbols is associated with a fixed structural reference on the hull, rather than a floating point like G or B?

✅ Before You Answer

• Be sure you know that KG is measured from a standard reference plane, usually the keel or molded baseline. • Eliminate any symbol that represents a quantity changing with loading, like displacement (Δ) or a floating point like B. • Choose the option whose symbol you would expect to see at the origin (zero height) on a ship’s vertical reference diagram or hydrostatic data sheet.