What does the term "restricted visibility" refer to in navigation?

The term "restricted visibility" in navigation refers to situations where visibility is impaired by weather conditions, such as fog, rain, snow, or haze. These atmospheric conditions can significantly reduce the distance a navigator can see, affecting their ability to safely operate a vessel. Restricted visibility is a crucial consideration because it directly impacts a mariner's ability to detect other vessels, navigational aids, and potential hazards in the water.

Weather conditions that lead to impaired visibility can result in the need for additional navigational precautions, such as maintaining a proper lookout, using radar, or sounding fog signals, all crucial for ensuring safety at sea. This definition captures the essence of how various weather phenomena can hinder visibility rather than merely focusing on specific numerical distances or lighting conditions unrelated to weather.