Which type of draft mark is used to maintain reserve buoyancy?

• A. Calculative
• B. Limiting
• C. Navigational
• D. Plimsoll

Answer: (B)

Limiting draft marks indicate the maximum permissible draft to keep enough reserve buoyancy. Reserve buoyancy is the extra buoyant volume of the hull that remains to help the vessel stay afloat if flooding or hull damage occurs. Staying within the limiting draft ensures there’s still enough submerged hull volume to provide that safety margin. If you load beyond this mark, the ship sits deeper in the water, reducing the reserve buoyancy and increasing the risk of sinking if damage occurs. The Plimsoll line, while related to safe loading under different water conditions, does not specifically designate a limit to preserve reserve buoyancy, and the other terms aren’t used to describe a draft mark with that purpose.