🔍 Key Concepts

• Free surface effect and how it reduces initial metacentric height (GM) • Relationship between free surface moment (FSM), displacement, and the FS correction (FSC or FSCT) • Units: how FSM units compare to GM units (e.g., ft-tons vs. feet)

💭 Think About

• Ask yourself: free surface moment is usually in units like ft-tons. What must you do to those units to end up with a correction in feet, like GM? • Think about the stability formula you’ve seen: GM(corrected) = GM(initial) minus (something involving free surface and displacement). How do you isolate that "something"? • Consider whether making the ship heavier (larger displacement) would make the free surface correction larger or smaller, and how that matches the math operation.

✅ Before You Answer

• Verify what units FSMT (total transverse free surface moment) typically has and what units the FSCT (correction) should have • Check the standard stability formula where FSM and displacement appear together and see which one is in the numerator and which in the denominator • Confirm whether the correction should increase or decrease when displacement increases, based on physical intuition about a heavier vessel’s sensitivity to free surface