Which of the following would NOT be considered a bottom piping arrangement on a tank ship?

• A. Direct
• B. Loop
• C. Free-flow
• D. Cross-connected header

Answer: (D)

Bottom piping arrangements describe how cargo is routed from the tank bottom to the discharge system to drain the tank efficiently. The aim is to minimize residual cargo and keep drainage straightforward.

Direct bottom piping is a straight path from the tank bottom to the pump or discharge point, providing a simple, uninterrupted line that aids complete drainage. Loop bottom piping adds a looping section in the bottom piping to improve flow characteristics, help with priming, and reduce the chance of air pockets or stagnant areas. Free-flow bottom piping means the bottom line is unobstructed and can drain by gravity into the discharge system, maximizing drainage efficiency.

A cross-connected header, however, is not a bottom piping arrangement. It refers to a top- or mid-system concept where multiple tanks’ lines are connected to a common header to distribute or transfer cargo, rather than being a bottom-path drainage configuration. Therefore, it does not fit as a bottom piping arrangement.