BOATsmart! USA Knowledge Base

Masthead Light:

Color: White.

Arc:  Shows a solid light over a sweep of 225° from the front of the boat to 22.5° on either side of the bow.

Position: Centered in the boat, facing forward. On common powerboats, this light is often on a short pole on top of the cabin, windshield or at the stern. 

Port Sidelight:

Color: Red.

Arc: Showing an unbroken light over an arc of 112.5° that is visible to other boats approaching from the port (left) side or from head-on.

Position: Forward, left area of the boat.

Starboard Sidelight:

Color: Green.

Arc: Showing an unbroken light over an arc of 112.5° that is visible to other boats approaching from the starboard (right) side or from head-on.

Position: Forward, right area of the boat.

Sternlight:

Color: White.

Arc: Shows an unbroken light over an arc of 135°.

Position:  Placed at the stern (back) of the boat.

All-around Light:

Color: White.

Arc: Shows a solid light over 360° (all around the boat).

Position:  Clearly visible from all directions.

Note: The all-around light functions as a combined masthead and sternlight–this light must be visible in all directions and must be at least 1m higher than the sidelights. 

Tricolor Light:  

Color: Green, red and white.

Arc: Combined, the light is a 360° view. The white section is at the stern (135°), the red section is portside and extends to the bow (112.5°) and the green section is on the starboard side extending to the bow (112.5°).

Position: It is placed where it can be seen from all directions.

Note: This light combines the stern and sidelights and is applicable only to wind-powered sailboats. The tricolor light can be used in place of the side lights/sternlight combination but must not be used when the sidelights are on. Either option is acceptable when used on its own. 

Towing Light:

A towing boat that is 30 feet in length or longer must display two white masthead lights on top of each other at night to indicate that it’s towing another boat. Use this rhyme to remember: White over white, towing at night! 

Law Enforcement Light:

If you should see a flashing blue light on the water, this is a law enforcement boat and you should be careful to stay out of its way. Use this rhyme to remember: Flashing blue could rescue you!