🔍 Key Concepts

• Free surface effect (FSE) and how it affects a vessel’s KG and stability • The formula for free surface correction (FSC) and where the moment term appears • Difference between displacement and moment (weight vs. weight × distance)

💭 Think About

• Ask yourself: when we talk about a “correction to KG,” are we dealing with a pure distance, a pure weight, or a moment (weight × distance)? • Which quantity, when divided by the vessel’s displacement (total weight), gives a distance that can be added to or subtracted from KG? • Look at each option and decide: which one has the correct physical units so that, after dividing by displacement, the result is in meters/feet (a KG correction)?

✅ Before You Answer

• Make sure the numerator has units of moment (ton-meters, ft-tons, etc.), not just weight or distance alone. • Verify that displacement is in units of weight (long tons, metric tons, etc.), so that moment ÷ weight = distance. • Eliminate any option that would give you the wrong units after division (e.g., distance, pure weight, or a dimensionless number instead of a distance).