The Maritime and Coastguard Agency (MCA) in UK has sent a notice recently asking boat and vessel owners to refrain from using white LED retrofits in traditional tungsten filament tricolor navigational lights.

Replacing filament bulbs with white LEDs in tricolor navigational lights could result in vessels not being insured. 

Colored light fittings designed to use filament bulbs are not suitable for LEDs, claim the Cruising Association’s Regulation and Technical Services team (RATS), and therefore in the event of an incident could invalidate insurance.

White LEDs do not emit the wavelengths required to correctly illuminate the red and green sectors, and, as a result the colors observed are totally outside of the IMO specifications.

In addition, a tungsten filament bulb has a single vertical wire as the light source, whereas LEDs emit light path angles greater than the permitted 2 degree cut-off limit between tricolor sectors.  A boat’s heading will therefore be unclear to another vessel over a significant arc, and, the merging beams will give strange colors as they overlap.

This issue does not affect navigation light fittings designed to take LED bulbs. The MCA has issued a Guidance Note highlighting these problems, and a warning not to use LED white replacement bulbs in equipment designed for filament bulb use.

The Cruising Association’s RATS will be at the Southampton Boat Show on the 11th of September with a navigation light to demonstrate the issues.

The full MCA notice can be viewed here.