All inlets and discharges led through the vessel's hull below the line drawn parallel and not less than six inches above the load waterline shall be fitted with

• A. an efficient and accessible means of closing
• B. a shutoff valve
• C. a screen or strainer
• D. an audible alarm

Answer: (A)

The main idea is to keep hull openings that are below the waterline from becoming flood points. When an opening through the hull is below the waterline, water can rush in if something breaches or pressure pushes through. That’s why these openings must have an efficient and accessible way to close them. A closing device—whether a valve, a watertight cap, or another closure—that works reliably and can be reached quickly by the crew is required. It ensures you can seal the opening promptly in an emergency to prevent flooding and help maintain the vessel’s buoyancy and stability.

Screens or strainers don’t stop flooding; they only filter debris. An audible alarm helps detect a problem but doesn’t seal the opening. A shutoff valve is one type of closing device, but the regulation calls for the broader concept of an efficient closing means that is accessible, which is why the general phrase is correct.