Marine Navigation Lights

Typically, a specific but basic light pattern is required of most marine vessels so that they can be used to show other boats where they are positioned during foggy weather and can among other things prevent boat crash incidents. In the same way that aircraft must have a specific set of patterned lights that alert neighboring aircraft of their position, so too do boats and other marine vessels have various navigational marine lights. For more information on this, read the article below. 

Marine Navigation Lights Importance 

The standard marine navigational lights include a green sidelight on the starboard side, a red sidelight on the port side, and a white light mounted as close as possible to the stern, and facing aft.  The definition of each type of light should abide by the famous Rule 21 in boating, which concerns masthead lights, sidelights, stern lights, towing lights, all-round lights or task lights, and flashing or special flashing lights (task lights are those lights which place the vessel in a special condition). The rules state that all of the side lights should be illuminated for 112.5 degrees, from straight ahead to 22.5 degrees abaft the beam. Additionally, the stern light has to be visible for about 135 degrees, and at 22.5 degrees after the beam on one side, and continuing around the stern to 22.5 degrees abaft the beam on the other side. Combined, this trio of lights produces a 360 degree circle of illumination around the marine vessel. In regards to most vessels that are about  20 meters or greater, each of the three lights must be isolated from the rest. Whereas on a vessel less than 20 meters, the side lights can be blended into use as a single lantern. 

Once this basic light pattern has been established, additional lights are added based upon vessel type, job function, maneuverability, and size.  A power driven vessel adds a white “masthead” light visible over a 225 degree arc from 22.5 degrees abaft the beam around the front to 22.5 degrees abaft the beam.  The masthead light (also known as a steaming light) must be higher than the sidelights, and when added to the stern light completes a 360 degree circle of white light around the vessel. Any power driven vessel 50 meters or longer, must add a second masthead light aft of, and higher than the previous masthead light.

Some final guidance for anyone looking to navigate the rules for marone lights, it’s best to  refrain from displaying a tricolor simultaneously as the normal navigation lights. This is because the red part of the tricolor light that hovers over the red navigation light indicates that a vessel is not under control. Additionally it is recommended not to ever show a tricolor while motoring as it can be confusing for passerby boats. 


If you are looking to acquire navigational lights get in touch with our team today! At RFQ Experts, owned and operated by ASAP Semiconductor, we can help you find all the unique parts for the aerospace, civil aviation, and defense industries. We’re always available and ready to help you find all the parts and equipment you need, 24/7-365. For a quick and competitive quote, email us at or call us at  +1-714-705-4780.


January 23, 2023

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