On a vessel of 12,000 tons displacement, a tank 60 feet long, 50 feet wide, and 20 feet deep is half filled with fresh water (SG 1.000) while the vessel is floating in saltwater (SG 1.026) What is the reduction in metacentric height due to free surface?

Correct Answer: Option D — 1.44 ft.

Free surface effect accounts for liquid density ratios. The formula FSC = (l × b³ × ρ_liquid) / (12 × Displacement × ρ_water) incorporates freshwater density (1.000) versus saltwater (1.026), dimensions 60'x50', and 12,000 tons displacement, yielding a 1.44 ft GM reduction.