Which of the following is a type of drainage used aboard?

Which of the following is a type of drainage used aboard?

• A. Primary drainage
• B. Gravity drain
• C. Overflow drainage
• D. Main drainage

Answer: (D)

Main drainage is the ship’s central sanitary drainage network that collects wastewater from fixtures across the vessel and sends it to the discharge path or holding/treatment system. It’s the primary system because it ties together all spaces into one coordinated network, ensuring all gray water and sewage from sinks, showers, and similar fixtures are removed efficiently. Other terms describe how water moves or refer to smaller subsystems rather than the comprehensive network used aboard, so they don’t denote the standard drainage setup on a ship.

Main drainage is the ship’s central sanitary drainage network that collects wastewater from fixtures across the vessel and sends it to the discharge path or holding/treatment system. It’s the primary system because it ties together all spaces into one coordinated network, ensuring all gray water and sewage from sinks, showers, and similar fixtures are removed efficiently. Other terms describe how water moves or refer to smaller subsystems rather than the comprehensive network used aboard, so they don’t denote the standard drainage setup on a ship.