Boating Basics: On the Water

Nighttime Navigation

Be on the lookout for the lights of other vessels when boating at night. Several types of lights serve as navigational aids at night. There are four common navigation lights.

Powerboat showing all-round white light and red and green sidelights

Sidelights: These red and green lights are called sidelights (also called combination lights) because they are visible to another vessel approaching from the side or head-on. The red light indicates a vessel';s port (left) side; the green indicates a vessel's starboard (right) side.

Sternlight: This white light is seen from behind the vessel.

Masthead Light: This white light shines forward and to both sides and is required on all power-driven vessels. A masthead light must be displayed by all vessels when under engine power. The absence of this light indicates a sailboat under sail.

All-Round White Light: On power-driven vessels less than 39.4 feet in length, this light may be used to combine a masthead light and sternlight into a single white light that can be seen by other vessels from any direction. This light serves as an anchor light when sidelights are extinguished.

Encountering Vessels at Night

Combinations of Navigation Lights	Illustrations of Lights
A white and a green light: When you see a white and a green light, you are the stand-on vessel. 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!
Only a white light: 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!
A red and a white light: 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!
A red, a green and and a white light: 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!
A red and a green but no white light: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 except when it is overtaking or in a narrow channel.	See only a green light... Movie: See the action!
	See only a red light... Movie: See the action!

Michigan Department
of Natural Resources

Get Started!

Boating Basics

It's the Law!

Michigan Info

Printable PDF Version
of Handbook

< Back to Previous Page

Table of Contents

Go to Next Page >

Online boating safety handbook last modified: April 22, 2008
Email with questions or comments about this web site.