Question 54 ONC01 - Master/Chief Mate Unlimited Tonnage

The Correct Answer is B. ### Why Option B ("Center of buoyancy") is correct: The center of buoyancy ($\text{CB}$) is defined as the geometric center (centroid) of the volume of water displaced by the immersed portion of the hull. According to Archimedes' principle, the total upward buoyant force acts through this point. Therefore, the term that defines the center of volume of the immersed portion of the hull is the **Center of buoyancy**. ### Why the other options are incorrect: * **A) Center of gravity ($\text{CG}$):** This is the single point through which the entire weight of the ship (including structure, cargo, fuel, etc.) is considered to act downwards. It relates to the mass of the entire vessel, not the volume of the immersed portion. * **C) Center of flotation ($\text{CF}$):** This is the geometric center (centroid) of the waterplane area. It is the point about which the ship trims and lists, but it describes an area, not the volume of the immersed hull. * **D) Tipping center:** This is not a standard, recognized hydrostatic term in naval architecture. While "tipping" relates to stability, the specific term defining the center of the immersed volume is the Center of buoyancy.