Seeing a red and a green light but no white light indicates you are approaching which type of vessel?

When you see a red and a green light without any white light, you are approaching a sailing vessel. In maritime navigation, sailing vessels are equipped with specific lights that indicate their position and direction. The red light indicates the port side (left side when facing forward), while the green light indicates the starboard side (right side when facing forward). The absence of a white light suggests that this is not a powered vessel but rather one that relies on sails for movement.

Other types of vessels, such as powered, fishing, or commercial vessels, typically display additional lights, including white lights for better visibility. The configuration of red and green lights, without a white light, is a specific indication of a sailing vessel that is underway, allowing other boaters to identify its navigational status and take appropriate measures to ensure safe passage.