🔍 Key Concepts

• Liftboat structure and legs – how the legs are arranged and what happens if one leg floods while the vessel is afloat and moving • Center of gravity (CG) vs. buoyancy – how added weight low and off to one side affects stability • Reserve buoyancy and displacement – what these terms actually mean and how flooding changes (or doesn’t change) them

💭 Think About

• Picture a three‑ or four‑leg liftboat underway: if one leg floods, where is the extra weight located relative to the vessel’s centerline? • Ask yourself: does flooding a leg add buoyancy or weight? Does it make the vessel sit higher or lower in the water? • Which of the choices would clearly make the vessel less stable and more prone to listing when one leg is flooded?

✅ Before You Answer

• Be clear on the definition of reserve buoyancy (enclosed volume above the waterline) and whether water entering a leg increases or decreases that volume. • Review how righting moment behaves when weight is added low down versus when it is added off to one side. • Confirm how a flooded, off‑center structural member would affect the vessel’s center of gravity location relative to the centerline.