Question 4413 Deck General

The correct answer is A) waterplane area. The center of flotation for a vessel is located at the geometric center of the waterplane area, which is the area of the vessel that is submerged in the water. This is because the buoyancy force acting on the vessel is proportional to the volume of the underwater portion of the vessel, and the center of this buoyancy force is located at the center of the waterplane area. The other options are incorrect because the amidships section (B) refers to the midship cross-section of the vessel, the underwater volume (C) does not determine the center of flotation, and the above water volume (D) is not relevant to the location of the center of flotation.