Boat Navigation at Night

Night navigation presents additional challenges. You should always operate at a slower speed at night and be on sharp lookout for the lights of other vessels. The lights displayed by other vessels will help you determine whether they are operating under power or sail, and their direction of travel. Once you’ve determined this, you apply the same navigation rules used in the daytime. However, never assume that the lights of other vessels are working properly. Allow plenty of time and distance to give way if needed, even if the lights indicate you are the stand-on vessel–The vessel that must maintain its course and speed unless it becomes apparent that the give-way boat is not taking appropriate action; if you must take action, do not turn toward the give-way boat or cross in front of it.

Power-Driven Vessel Encountering Other Vessels at Night

Encountering Vessels at Night What the Lights Mean	Illustrations of Lights
When you see a green and a white light, you are the stand-on vessel–The vessel that must maintain its course and speed unless it becomes apparent that the give-way boat is not taking appropriate action; if you must take action, do not turn toward the give-way boat or cross in front of it. You should remain alert, however, in case the other vessel operator does not see you or does not know navigational rules.	Movie: See the action!
When you see only a white light, you are overtaking another vessel or it is anchored. It is the stand-on vessel, whether underway or anchored. You may go around it on either side.	Movie: See the action!
When you see a red and a white light, you must give way to the other vessel! Slow down and allow the vessel to pass, or you may turn to the right and pass behind the other vessel.	Movie: See the action!
When you see a red, a green, and a white light, you are approaching another power-driven vessel head-on and both vessels must give way.	Movie: See the action!
Encountering Sailing Vessels at Night What the Lights Mean	Illustrations of Lights
When you see a red and a green light but no white light, you are approaching a sailing vessel head-on and you must give way.	Movie: See the action!
When you see only a green light or only a red light, you may be approaching a sailing vessel and you must give way. A sailing vessel is always the stand-on vessel–The vessel that must maintain its course and speed unless it becomes apparent that the give-way boat is not taking appropriate action; if you must take action, do not turn toward the give-way boat or cross in front of it except when it is overtaking.	See only a green light… Movie: See the action!
	See only a red light… Movie: See the action!