In a casualty situation, what is the primary concern before opening any watertight closures?

The primary concern before opening any watertight closures is to ensure that the closure is not under pressure. This consideration is critical because if a closure is under pressure, opening it could result in a sudden influx of water or other hazardous materials, posing serious risks to personnel and compromising the safety of the vessel. Maintaining structural integrity is vital in a casualty situation, and verifying that no pressure is present ensures that potential dangers can be mitigated before action is taken.

While accounting for personnel, establishing communication channels, and preparing evacuation plans are all essential aspects of managing a casualty, the immediate safety of those involved hinges on assessing the pressure situation before proceeding with any closures. Thus, confirming that a closure is safe to open takes precedence to protect personnel from sudden hazards.