What do visible red and green lights indicate when encountering another vessel in darkness or reduced visibility?

The visible red and green lights seen when encountering another vessel at night or in reduced visibility have specific meanings that relate to the type and direction of the vessel. The red light is positioned on the port (left) side while the green light is on the starboard (right) side. When these lights are observed together, they indicate that the vessels are approaching each other head-on. The configuration of the lights signifies that you are likely facing the other vessel directly in the forward position.

When navigating, recognizing these signals is critical for safe boating practices. The presence of these colored lights suggests that both vessels need to take appropriate action to avoid a collision, enhancing situational awareness during nighttime navigation.

The other interpretations of lights on vessels, such as being at anchor or moving away, do not align with the specific combination of visible red and green lights, which is unique to vessels that are under way and facing one another. Understanding these light signals is fundamental for maintaining safety on the water.