Boat Navigation Lights: Colors, Placement, & Visibility Requirements

Desi89

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posted on 1 year ago — updated on 1 second ago

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Ahoy! You may be less likely to rear-end someone if you’re sailing a boat at night than if you were driving a car in bumper-to-bumper traffic, but it’s still a real—and dangerous—possibility. Thankfully, strict sternlight requirements make it a lot easier to navigate on the water in the dark and give other boats a safe berth. In this article, we’ll go over the color and visibility requirements for sternlights (and other navigation lights) for sailboats and powerboats of varying lengths. Let’s get cruisin’!

Things You Should Know

A boat’s sternlight is white and shines over a 135 degree angle behind the boat. It must be visible from 2 nautical miles (2.3 mi or 3.7 km) away.
Masthead lights are also white and illuminate a 225 degree angle in front of the boat. The port (left) and starboard (right) sidelights are red and green, respectively.
Boats under 12 m (39 ft) long can use a single, white all-around light in place of separate masthead and sternlights.

Sternlight Color & Visibility Requirements

A sternlight is white and covers a 135 degree angle behind the boat. The sternlight is positioned as close to the stern (rear) of a boat as possible and alerts other sailors to your boat’s presence at night or during foggy or inclement weather. A sternlight must be visible from 2 nautical miles (2.3 mi or 3.7 km) away. All of your boat’s navigation lights, including the sternlight, must be on from sunset to sundown or when visibility is low, like if you’re sailing during a storm. The sternlight is also sometimes called an aft light (“aft” refers to the stern section of a boat).

Other Navigation Lights

Masthead lights are white and illuminate 225 degrees ahead of the boat. The masthead light faces forward and must be at least 1 m (3.3 ft) above the colored sidelights if your boat is under 12 m (39 ft) long, or 2.5 m (8.2 ft) above the sidelights if your boat is longer. Masthead lights must be visible for 3 nautical miles (3.5 mi or 5.6 km) if your boat is over 12 m (39 ft) long, or 2 nautical miles (2.3 mi or 3.7 km) if it's shorter. The masthead and sternlight combined ensure that your boat is visible from 360 degrees.

The port (left) light is red and the starboard (right) light is green. The sidelights are positioned near the prow (front) of the boat and help onlookers determine which direction you’re traveling from far away at night. They must be visible from 1 nautical mile (1.2 mi or 1.9 km) away for boats under 12 m (39 ft) long, or from 2 nautical miles (2.3 mi or 3.7 km) away for longer boats. Both lights shine over a 112.5 degree angle. The colored sidelights are optional for boats less than 7 m (23 ft) long.

A white all-around light replaces the masthead and sternlights on small boats. All-around lights are visible from 360 degrees and can be used on boats less than 12 m (39 ft) long. It’s typically placed where the masthead light would go and must be at least 39 in (0.99 m) above the sidelights.

Navigation Light Requirements by Boat Size and Type

All boats up to 7 m (23 ft) Short powerboats and sailboats must display an all-around white light. The colored sidelights are optional, but are a good idea since they increase your visibility. This applies to vessels with oars and paddles too, like canoes, kayaks, and rowboats. On very small boats, a torch or flashlight is acceptable as long as it’s visible from 360 degrees.

Powerboats up to 12 m (39 ft) If you’re driving a mid-sized powerboat, you need a white all-around light that’s visible from 2 nautical miles (2.3 mi or 3.7 km) away. They must also have a pair of red and green sidelights that can be seen from 1 nautical mile (1.2 mi or 1.9 km) away. The all-around white light must be at least 39 in (0.99 m) above the sidelights.

Sailboats up to 20 m (66 ft) If you’re sailing a sailboat at night, your boat must have a white sternlight visible from 2 nautical miles (2.3 mi or 3.7 km) away and colored sidelights that can be seen for 1 nautical mile (1.2 mi or 1.9 km). Vessels of this type and size can use independent white, red, and green lights or a tricolor combination light in their place. Tricolor lights shine white, red, and green lights in the appropriate direction and cannot be displayed at the same time as regular sidelights. A tricolor light indicates the boat is sailing and not using power. It can't be used if the sailboat is using a motor (whether the sails are hoisted or not). Tricolor lights are positioned toward the front of the boat where the masthead light would normally go.

Powerboats up to 20 m (66 ft) Longer powerboats need separate masthead and sternlights. The masthead light must be visible from 3 nautical miles (3.5 mi or 5.6 km) away, while the sternlight only needs to be seen from 2 nautical miles (2.3 mi or 3.7 km) away. The colored sidelights need to shine for 2 nautical miles (2.3 mi or 3.7 km). Masthead lights must be at least 8 ft (2.4 m) above the gunnel (the outermost top edge of a boat’s hull, usually where the deck and the hull meet).

All boats over 20 m (66 ft) All large boats need a sternlight and colored sidelights visible from 2 nautical miles (2.3 mi or 3.7 km) and a masthead light visible from 5 nautical miles (5.8 mi or 9.3 km) away.

All boats under 50 m (160 ft) at anchor Unless you’re anchoring your boat in a designated, well-lit area like a marina, it needs to have an all-around white light visible from 2 nautical miles (2.3 mi or 3.7 km) away. This applies to all boats regardless of size or whether it’s a powerboat or sailboat.