When must you Maintain a proper lookout using human sight applies to boats under what circumstances?

Maintaining a proper lookout using human sight is essential for all boats, particularly when visibility is limited due to factors like darkness, fog, rain, or heavy traffic. This requirement is crucial for avoiding collisions and ensuring the safety of all vessels on the water. Additionally, a proper lookout should be maintained at all times, regardless of the conditions, to detect other vessels, navigational hazards, and changes in the environment. It is part of the broader responsibility to navigate safely and responsibly.