Question 2018 Deck Safety

The correct answer is A) virtual height of the center of gravity. Reducing free surfaces has the effect of lowering the virtual height of the center of gravity (VCG) of the vessel. This is because free surfaces, such as liquids in tanks, can cause the center of gravity to rise, reducing the vessel's stability. By reducing these free surfaces, the VCG is lowered, which in turn increases the vessel's metacentric height (GM) and overall stability. The other options are incorrect because they do not directly relate to the effect of reducing free surfaces. Option B refers to the uncorrected KG, which is not directly affected by free surface reduction. Options C and D relate to the metacenter and metacentric height, which are indirectly affected by the change in VCG resulting from free surface reduction.