What Are Masthead Lights?
Masthead lights (noun): A masthead light is a white navigation light mounted on the front part of a boat or ship's mast. It shines continuously over a 225° arc, covering the area from directly ahead to 22.5° abaft (just behind) the beam on both sides.
These lights are required on all power-driven vessels underway and are essential for collision prevention during nighttime or low-visibility conditions.
Why Masthead Lights Matter
Masthead lights help other mariners identify:
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The presence of your vessel
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Its direction of travel
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Whether it’s powered and underway
They’re part of the International Regulations for Preventing Collisions at Sea (COLREGs) and are mandatory on powered vessels in most navigable waters.
Visibility Requirements by Vessel Size
| Vessel Length | Required Visibility Range |
|---|---|
| Under 39 feet (12m) | 2 nautical miles |
| 39 to under 65 feet (20m) | 3 nautical miles |
| 65 to under 164 feet (50m) | 5 nautical miles |
| 164 feet and over (50m+) | 6 nautical miles |
⚠️ Always check with your local maritime authority or coast guard for region-specific rules. Some areas may have additional requirements.
Masthead Light Styles
Modern masthead lights come in different forms, including:
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Standalone LED masthead lamps – Efficient and bright with long lifespans
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Tri-color combo lights with anchor light – Combine masthead, port, starboard, and anchor lights into a single fixture for sailboats and smaller yachts
Popular with commercial and recreational boaters alike, LED masthead lights are a top choice for energy savings and reliability at sea.
Example in a Sentence
"Before entering the harbor at dusk, the skipper switched on the masthead light to signal they were under power and underway."
Synonyms
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Steaming light
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Mast light
Related Terms
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Navigation Lights – All lights used for signaling presence and status
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Running Lights – The combination of masthead, sidelights, and stern light
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Signal Light – Any light used for communication on the water
Would you like an infographic or diagram to pair with this content? I can create one showing typical masthead light placement or visibility angles.