Abstract: A ship has a plurality of open-top recesses in the deck thereof in which substantially fluid-tight, relatively light-weight, buoyant containers are held solely by the force of gravity and by frictional forces. Those containers substantially fill those recesses. If the ship were to sink, the containers would automatically eject, responding to the weight of the water which they displaced to rise up out of those recesses and float upright in open water. Thereafter, those buoyant containers would confine the contents thereof until those containers could have the contents thereof transferred into other ships at sea or could be towed to shore to be emptied, thereby preventing accidental spills of oil or other liquid cargo.