When should navigation lights be displayed according to the Rules?

Navigation lights should be displayed from sunset to sunrise and during restricted visibility to ensure the safety of all vessels at sea. This requirement is in place to make vessels visible to one another during times when visibility is low, thereby reducing the risk of collisions. Displaying navigation lights during these conditions helps convey a vessel's position, heading, and status to other mariners.

Navigating in the dark or in restricted visibility such as fog creates increased hazards due to limited sight distances. By adhering to this rule and using navigation lights appropriately, vessels can communicate their presence and movements to one another effectively. This is a critical aspect of maintaining maritime safety and following the established Rules of the Road.

In contrast, displaying lights only during inclement weather, at night, or just when entering or leaving a harbor does not align with the comprehensive safety measures intended by the Rules of the Road, which prioritize consistent visibility for all vessels throughout various conditions.