Which marking indicates the presence of a partly submerged object being towed?

• A. A diamond shape on the towed object
• B. A square shape pennant
• C. A searchlight beamed from the towing vessel in the direction of the tow
• D. An all-round light at each end of the towed object

Answer: (A)

The key idea is that a towed object, especially one that is partly submerged, must display a distinctive mark so other mariners know a tow is in progress and potential hazards exist. The diamond-shaped mark on the towed object is the standardized signal indicating this situation. It helps prevent collisions by alerting nearby vessels to the presence of the tow and its reduced maneuverability. The other options do not convey this towing-specific warning: a square pennant, a signaling beam, or all-round lights at the ends are not the standard indication for a partly submerged object being towed.