What is progressive flooding?

Progressive flooding refers to the entry of water into the hull of a vessel through openings that are not adequately sealed or due to damage that allows water ingress. This can occur when water flows into compartments and, if not controlled, can destabilize the vessel, leading to loss of stability and potential capsizing.

This phenomenon is critical to understand for maritime safety because it often results from down-flooding — where water enters through openings such as hatches, doors, or damaged sections of the hull when the vessel is heeled or listing. If a compartment fills with water, it can compromise the vessel's buoyancy and stability.

The other options do not accurately describe progressive flooding. For example, flooding during heavy rains doesn't necessarily indicate issues with the vessel's integrity; it's more about water entering the environment rather than a structural failure. Similarly, flow of water from external sources does not specify that it is due to damage or condition of the vessel. The gradual filling of tanks with water may refer to a managed operation for fuel or ballast but does not depict the uncontrolled and dangerous nature of progressive flooding. Understanding this concept is crucial for effective emergency response and vessel design to mitigate risk.