Abstract: Transient Damage Strategy (TDS), for waterborn cargo and passenger vessels, functions to prevent or to greatly mitigate pollution of waters, and to reduce hazarding of stability and buoyancy of ships subsequent to underwater penetration of tanks and other water, oil, and air tight spaces. The TDS process, which incorporates the use of existing ship's systems and is comprised of common "off the shelf" components, with the exception of one valve, herein referred to as a "ventlock" valve, effectively functions to prevent liquid tank contents, such as oil, from escaping outboard through underwater hull penetration, to prevent water intrusion into empty spaces through underwater hull penetration, and to enable transfer of uncontaminated oil or other contents from damaged tanks to undamaged tanks.