give way
maneuver to avoid a collision
The vessels head is toward you, the green light is the starboard running light, the white light is the masthead light Actually since the red and green nav lights must be seen at an angle of 135 degrees from bow to aft of amidships and a stern light also is seen at least 135 degrees you could be behind and to starboard. If the white light is high off the water then it is most likely coming at you.
You are approaching the starboard side of another vessel
maneuver to avoid a collision
The port side of a vessel carries a red light, whilst the starboard side carries a green one. A white light would be either in the centre to act as a headlight or extra illumination for the benefit of other vessels, or on the masthead to indicate the height of the boat.
You must maneuver to avoid collision.
Port (red) and Starboard (green) running lights and a white light which will be mounted on either the stern or the masthead.
Their port side (red) is towards you. Their white light, plus the red light, allows you to believe the other boat is off your starboard side (green). Provided they are not getting any closer, and the position of the Red and white light doesn't change (towards you) you can assume there will not be a collision
Port and starboard steaming lights and stern light
The head and starboard side of the vessel is toward you
Another boat is approaching you. The red light is their port side and the green light is their starboard side. The port side is left.
Another boat is approaching you. The red light is their port side and the green light is their starboard side. The port side is left.