Which of the following ballasting operations performed in conjunction with off-loading cargo could be accomplished without the use of a ballast pump?

Correct Answer: Option D — Filling a salt water ballast tank located below the waterline.

Gravity filling is possible when the ballast tank is located below the waterline. By opening the sea chest valve and the tank's filling valve, hydrostatic pressure forces seawater into the tank. This eliminates the need for a ballast pump, saving energy and reducing mechanical wear on the pumping system.