Question 2016 Deck Safety

The correct answer is C) waterplane area. The center of flotation of a vessel is the geometric center of the waterplane area, which is the horizontal plane at the surface of the water where the vessel floats. This is because the waterplane area is the primary determinant of a vessel's stability and buoyancy, and the center of this area represents the point around which the vessel rotates when heeling or listing. The other answer options are incorrect because they do not accurately represent the definition of the center of flotation. The underwater volume, above-water volume, and amidships section are all related to the vessel's geometry, but they do not specifically define the center of flotation.