When Boating At Night, What Does A Single White Light On A Boat Tell You?

Fact Checked By James A Rockey | Post Updated On: December 10, 2022
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A single white light on a boat tells you that the oncoming vessel has the right of way. White light can indicate that you are approaching another craft from behind, or you’re approaching a non-powered or anchored boat at night.

Key Takeaways

  • If you are planning to kayak or sail a boat then it is very important for you to understand how navigation lights work
  • When a boat is anchored, it shows an all-around white light to indicate that the craft is in anchor to other boats
  • If you are approaching a non-powered boat with no standard navigation lights then you have to use a lantern, flashlight, or electric torch and show a white light
  • If you are approaching a boat from behind then you have to show a white light and then pass the ship at a safe distance to the right or left side

What Does A White Light Indicate?

What Does A White Light Indicate

Whenever you see a white light on a boat, it means that you do not have the right of way. There are three scenarios where you will see a white light on a boat. Let’s look at each of the scenarios and what each of them means.

1. You Are Approaching An Anchored Boat At Night

An anchored boat exhibits an all-around white light to indicate that its craft is in anchor to other boats. Only the white light is visible on an anchored boat since they don’t display their red and green sidelights. The sidelights, which are red and green, are used for indicating that a craft is underway.

2. A Non-Powered Boat Is Approaching

When approaching a non-powered boat, you are required to yield the right of way since you are the overtaking or give-way boat. To do that effectively, you should take action early and keep a safe distance. You must pass the non-powered ship at a safe distance and speed, preferably on the right side if there’s a safe path. If you have a non-powered boat that doesn’t have standard navigation lights, you are required to use a lantern, flashlight, or electric torch showing a white light.

3. You Are Approaching A Boat From Behind

This is most common when boating at night. When only the white light is visible, it means you are approaching another vessel from behind, and you are required to change your cause bypassing at a safe distance to the right or left side. The white light is known as the stern light and is only visible from behind the vessel. 

What Lights Do I Need On My Boat?

In order to tell what lights you need to have on your boat, it is essential to understand the rules of navigation lights and what each light means. This section takes you through the different navigation lights when to use them, and other rules that will help you understand these lights clearly.

Navigation lights are essential for safe navigation between sunset and sunrise and when there’s fog, rain, and other conditions that may reduce visibility. These lights help to avoid collisions by identifying the give-way vessels. Below are the different types of navigation lights found on boats:

1. Stern Light – this is a white light that is usually on the boat’s stern and is only visible from behind the vehicle 

2. Combination Lights Or Sidelights– these are green and red lights that are only visible to approaching vessels. The green light is usually on the starboard or right side of the vessel, while the red light is on the vessel’s port or left side.

3. Masthead Light – this white light is a requirement on all engine-powered vessels that are 39.4 feet or longer. The light shines forward and to both sides. For vessels shorter than 39.4 feet, the masthead and stern lights are replaced by an all-around white light seen from all directions.

What are the rules determining which navigation lights should be displayed on a vessel?

The type of navigation lights to be displayed on a vessel depends on: 

1. The Vessels Length

A boat that is 34.9 feet or less and is powered should have red and green sidelights that illuminate 112.5 degrees and are visible from a distance of up to one mile. This type of vessel should also have a white light all around illuminating 360 degrees and is visible from a distance of up to 2 miles. The white light should be positioned above the sidelights at a distance of 39 inches.

For a powered boat that is longer than 39.4 feet but shorter than 65.6 feet, the navigation rules require it to have one masthead light illuminating 225 degrees for two miles, a set of red and green and red lights illuminating 112.5 degrees for one mile, and one stern light illuminating 135 degrees for two miles.  The combined radius of the stern light and masthead light should be 360 degrees, and the masthead should be at least 8 feet above the upper edge of the boat.

2. Whether The Vessel Is Underway Or At Anchor

An underway vessel should have all the lights we’ve mentioned above, depending on the boat’s length. For a boat at anchor, especially in non-designated anchor areas like a marina, all-around white lights are required to ensure the boat is visible from all directions by the nearby vessels.

3. Whether The Vessel Is A Sailboat Or Engine Powered

All sailboats operating at night or in periods with restricted visibility are required to have a white stern light illuminating 135 degrees for two miles and a set of red and green sidelights decorating 112.5 degrees for one mile.

These vessels are allowed to use independent white and sidelights or a tricolor light that combines all of them into a single unit. Tricolor lights should not be used on a powered boat under any circumstances or displayed simultaneously as regular sidelights.

For sailboats under 23 feet, they are only required to display a white light which can be a flashlight or lantern when sailing at night or in limited visibility. Rowboats, kayaks, and canoes are also required to display a white light during these periods.


Understanding navigation lights are essential for anyone getting on the water, especially at night. Even if you are kayaking, you need to know what the lights on sailboats and motorboats mean to avoid colliding with other vessels. We hope this article answers your question and helps you understand the different types of boat lights and what they mean.


  • https://www.boatsmartexam.com/knowledge-base/article/boat-navigation-at-night-2/
  • https://www.quora.com/When-boating-at-night-what-does-a-single-white-light-on-a-boat-tell-you
  • https://www.boat-ed.com/indiana/studyGuide/Common-Navigation-Lights/10101602_35209/

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