Masthead Lights


Definition of Masthead Lights

Masthead lights are a specific type of navigation light found on boats and ships, designed to indicate the vessel's presence, course, and status to other nearby watercraft.

Mounted on the forward part of a vessel's mast, these white lights shine at an unbroken arc of 225 degrees, visible from the bow to 22.5 degrees abaft the beam on either side.

navigation light placement schematic

Masthead lights are required for all power-driven vessels while underway and must be visible from a distance determined by the size of the vessel.

Their primary purpose is to help prevent collisions at sea by indicating the location and direction of vessels to other mariners in low visibility conditions or during nighttime operations.

Although there can be minor variations in regulations across different countries, most nations adhere to the standardized rules set by the International Regulations for Preventing Collisions at Sea (COLREGs).

The rules outline the visibility requirements for masthead lights based on the size of the vessel, as displayed in this table:

Vessel Length Masthead Light Visibility Range
Less than 39 feet 2 nautical miles
39 feet to less than 65 feet 3 nautical miles
65 feet to less than 164 feet 5 nautical miles
164 feet and above 6 nautical miles

Important: Specific countries or local jurisdictions may have additional regulations or slightly different requirements for navigation lights, so it is essential to consult local maritime authorities or coast guards for accurate information.

For example, the US Coast Guard requires boats under 39 feet to have a sound signal while international regulations make no such requirement.

Masthead lights can be found in various styles and sizes, suitable for different types of vessels.

They can be standalone fixtures like this LED Masthead Lamp or integrated into a tiered combination light that includes the red and green lights as well; for example, the LED Tri-Color with Anchor Lamp.

LED technology is commonly used for masthead lights, offering energy efficiency, long life, and excellent brightness.

Example of Masthead Lights in a Sentence

"Upon entering a busy channel, the captain of the commercial vessel turned on the masthead light to signal to other vessels in the area that they were underway and to make their presence known."

Synonyms: mast light, steaming light

Related Terms for Masthead Lights