USCG Safety Alert - Navigation Lights Suitability of Vertical Arc of Visibility

[Montanan]

The United States Coast Guard has issued a safety alert regarding the misapplication of navigation lights which have distinct vertical arc of visibilities for power boats as to their incorrect usage on sailboats.

The issue: "If your sailboat does not have the correct lights (sidelights, masthead lights, all-round lights, and/or combined lantern) and it heels past a certain degree, it may not be observable by other vessel operators."


"Not all navigation lights are created equal.

Navigation lights intended for use on power driven vessels may be different from navigation lights intended for use on sailing vessels. Although the horizontal arc of visibility is the same for all lights, the vertical divergence (i.e. vertical arc of visibility) requirements for lights on vessels under sail are larger to accommodate greater heeling. Manufacturer labeling may not discriminate between the different requirements. Navigation lights that claim compliance with the navigation rules may meet the vertical visibility requirements for a power driven vessel, however, they may not comply with the vertical visibility standards for sailing vessels. Manufacturer labeling may not indicate that the lights are designed for use on power-driven vessels only."

Reference document for details and descriptions of COLREG standards:

https://www.dco.uscg.mil/Portals/9/D...lerts/0219.pdf