Guide to Navigation LightsNavigation lights on vessels serve several purposes. Interestingly, they are not intended to illuminate to boat operators what lies ahead, but instead, to make a vessel visible to others. Navigation lights also communicate information about a vessel’s purpose, size, and direction of travel to others in its vicinity.  

Though the International/Inland Rules describe hundreds of light configurations to identify vessels of all sizes with a range of purposes, they all share one thing in common with comparatively small recreational boats: all must show red (portside) and green (starboard side) running lights, and a white stern light when underway between local sunset and sunrise and during periods of restricted visibility. Also, any vessel at anchor must show an anchor light. 

The phrases between sunset and sunrise and periods of restricted visibility deserve a bit more explanation. While between sunset and sunrise is pretty self-explanatory, boaters need to be aware of when sunset occurs in their local area as well as when daylight saving time changes, if applicable. Television and web-based weather forecasts always indicate sunset/sunrise times and it is prudent to check this data when planning a voyage. In parts of the country where daylight savings is in effect, remember that it reverts to standard time on the first Sunday of November. 

Keep in mind that restricted visibility is defined as “any condition in which visibility is restricted by fog, mist, falling snow, heavy rainstorms, sandstorms or similar cause.” These weather phenomena can pop up with very little notice and, in such situations, require that navigation lights be illuminated. The most frequent excuse boat owners use when their boat’s navigation lights are not operating is that they boat only during the day. While certainly logical, the defense will not fly with most marine law enforcement agencies because, as mentioned above, the law requires that navigation lights be used during periods of restricted visibility, which of course, can occur during daylight hours.    

Short History of Navigation Light Rules 

Current rules governing navigation lights are rooted in international conventions that date from 1838. Though updated several times between then and 1948, the laws have changed little in the 65 years since. By necessity, the laws are very detailed in order to identify the variety of vessel types that now sail the seven seas. For example, special purpose vessels (minesweepers, dredges, high-speed ferries, commercial fishing vessels, and tugboats, as well as ships at anchor) have distinctly different navigation light configurations.

For a full presentation of the federal rules governing navigation light on recreational boats, see the Boater’s Guide to the Federal Requirements for Recreational Boats, available here or through local units of the U.S. Coast Guard Auxiliary or U.S. Power Squadron.  

Basic Rules on Boating Navigation Lights

  • Running lights (also called sidelights) are required on most all vessels, depending on length. Running lights are red for port and green for starboard, and shine from dead ahead of a vessel to 112.5 degrees aft, on either side. Depending on vessel configuration, the locations of running lights vary. Running lights also include the stern light, which is always white and, as the name implies, located on the stern. All-round stern lights shine through 360 degrees.  
  • Powerboats under 65.5 feet are required to show running lights, a stern light, and a masthead light. Combination lights on the bow can be used.  
  • Vessels between 39.4 and 164 feet must show a white masthead light shining from 112.5 degrees on the port side through dead ahead and to 112.5 degrees on the starboard side. Boats in this category must also display a white stern light shining aft and 67.5 degrees to either side of dead astern. 
  • Power vessels less than 39.4 feet may show a single all-round light instead of separate masthead and stern lights. 
  • Sailboats under power are considered powerboats and running lights may be combined into a single bicolor combination light. 
  • Sailboats under 65.5 feet must show running and stern lights, which may be combined into a bicolor light and stern light, or a single tricolor light at the mast top. 

The good news for recreational boat renters is that the Coast Guard has simplified navigation light regulations, which are now focused primarily on vessel length instead of vessel use. Further, the Coast Guard has developed standards for original navigation light equipment installed on boats. Thus, a boat renter can be assured that the location and configuration of navigation lights on a rental are legal for a vessel of its length and purpose. 

Checking Navigation Lights

Here are some guidelines for checking navigation lights:  

  • Thoroughly investigate the condition of the lights on a vessel. This will ensure that they are watching properly, to use the nautical term, and that wire connections to the lights are secured. Also, determine if spare bulbs or electrical tape are on board. 
  • Know the location of the navigation lights on the boat. For example, some center console models have the lights affixed to the port and starboard sides of the console, inside the boat. Lights in this location can be unknowingly obstructed by passengers, which can cause confusion to other boats at night. 
  • Even though navigation lights affixed to the bow are generally out of the way, they can still be obstructed by trolling motors or anchor or personal gear, for example. If necessary, reposition the equipment so the lights can be seen.    
  • Pay particular attention to removable stern lights. Moisture can seep into the light stick receptacle and can cause the light to function improperly. 
  • A boat’s electrical system is configured so that the running lights can be extinguished when the vessel is not underway and so that only the stern light is illuminated. This communicates to other vessels that the boat is not underway and is at anchor, a critical distinction should a collision occur. 
  • If any lights do not operate, or the anchor and running lights do not work independently of each other, you may want to consult with the boat owner and determine if repairs or a bulb replacement can be accomplished on the spot. If not, you may want to consider scrubbing or postponing the voyage until repairs are made and the lights work correctly. 

Night boating can be a unique and fun experience, but keep in mind that the primary purpose of navigation lights is to make your boat visible to others at night. Knowing that the navigation lights on the boat you want to rent are in good working order will go a long way in providing some peace of mind to you and your passengers.