What does a red navigation light indicate on a vessel?

A red navigation light indicates the port (left) side of a vessel when facing forward. This standardized color coding is crucial for maritime navigation, especially during nighttime or in poor visibility conditions, as it helps to determine the direction and movement of vessels.

The rule of using red for the port side and green for the starboard (right) side is established internationally to prevent collisions by allowing vessels to see each other’s relative positions and headings. When approaching another vessel, if you can see the red light, that means the other vessel is on your left, indicating that you are on a collision course with it, and you should take appropriate action to avoid a collision.

This understanding of navigation lights is essential for safe navigation at sea, facilitating effective communication between vessels.