Lewith Tankers Exam 3 Practice

The function of a sump or surge tank is to act as a dedicated reservoir that accepts the heavier or residual liquids, dampens flow surges, and helps separate phases so the system can drain cleanly and operate smoothly. Heavy liquids tend to settle to the bottom, so the sump collects them, keeping the main tanks free of sludge and making it possible to pump those heavier components out when needed. This arrangement also aids complete drainage: the sump provides a low-point collection space that the pumps can draw from after the rest of the liquid has been removed, minimizing residual cargo left in the tanks. By serving as a buffer, the sump dampens pressure pulses in the cargo piping during loading and unloading, which reduces cavitation at the pump suction and helps protect the pumping system from surge damage. Additionally, because liquids with different densities can separate within the sump, it supports phase separation, keeping heavier and lighter components distinct and improving the quality of discharge or transfer. In short, the sump or surge tank is there to collect heavier constituents, enable thorough drainage, smooth out flow to prevent cavitation, and promote separation of phases for safer and more efficient operation.