In a head-on situation, what lights will you see from both vessels?

In a head-on situation at sea between two vessels, the expected configuration is that each vessel will display its navigation lights, which include a masthead light and sidelights. The masthead light is white and can be seen from any direction, typically mounted higher than other lights, and signifies that the vessel is underway. The sidelights are red and green: the red light is shown on the port side (left) of the vessel, and the green light is on the starboard side (right). When two vessels approach each other head-on, each will see one masthead light and two sidelights from the other vessel, indicating their respective positions and directions.

This configuration is crucial for avoiding collisions, as it helps each vessel determine if they are on a collision course or if they need to maneuver. Understanding the visibility of these lights in head-on encounters is fundamental for safe navigation and situational awareness at sea. Thus, the observation of one mast light and two sidelights from both vessels accurately reflects the correct navigation light display in such a scenario.