As daylight savings is upon us with earlier sunsets, let us take a moment to review proper navigation lights for nighttime boating. Remember, navigation lights should be turned on 45 minutes prior to sunset, left on until 45 minutes after sunrise, and during times of limited visibility.
The most common of our navigation lights are our “running lights”. This is a red light on the port side of the boat and a green light on the starboard side that shine from the bow to 22.5 degrees abaft the beam of the boat. This creates a 112.5-degree arc on either side of the vessel. To complete a 360-degree circle, our white stern light will shine 135 degrees from the stern of the boat. This 360-degree circle means a surrounding vessel will only see one of your lights at any given point (unless they are head on) and are able to identify which side of the boat they are seeing and who is the stand on vessel in crossing situations. This sequence of lights should be used while SAILING at night.
Once the engine is turned on, we are no longer a sailboat and must display a “steaming light” to identify as such. The most common steaming light is a single white light that shines forward of the mast in a 225-degree arc. Combined with the stern light, a boat under power will now be displaying a 360-degree white light in combination with its red and green lights. This sequence of lights should be used while MOTORING at night.
To review, if we are only seeing a green light, we know this is a sailboats starboard side. If we are seeing a green light with a single white light above it, this is now a powerboat’s starboard side. Remember that a sailboat becomes a powerboat once the engine is turned on.
Lastly, a boat anchored at night shall display a 360-degree white light atop the mast. While this is not required in designated anchorages, it is highly recommended. Pro Tip: Be sure to turn off your anchor lights once you have left the anchorage and are now sailing or motoring. This happens all too often and can cause confusion to surrounding boats.

Great article! Boat lights are the means of communication between sailing vessels. These lights are also a tool to let my presence known even from a distance.