What is an example of a restricted visibility situation?

A situation of restricted visibility is characterized by conditions that limit a mariner's ability to see other vessels, landmarks, and navigational aids. Heavy fog or rain that significantly reduces sight distance exemplifies restricted visibility, as these conditions can make it difficult for a vessel operator to detect potential hazards and other vessels, thereby increasing the risk of collision.

Under the USCG Rules of the Road, specific protocols must be followed under such conditions to enhance safety. For example, vessels must sound appropriate sound signals, use radar if available, and take measures to ensure safe navigation.

In contrast, clear sunny days without clouds, night time with full moon visibility, and calm waters with no traffic all represent conditions where visibility is not restricted and navigational challenges are minimized.