LED lights pose risk in an emergency, warns marine safety watchdog

The US Coast Guard this week issued a warning that LED lights used to replace conventional incandescent light globes could interfere with the VHF waveband, used globally for communicating with marine rescue services.

The Australian Maritime Safety Authority has followed in its wake, linking to the Coast Guard’s announcement via its social media channels.

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Services affected include Digital Selective Calling (DSC) that can alert nearby boats of another vessel’s location in an emergency, and the Automatic Identification System (AIS) that allows boats to electronic ally see each other in low visibility.

According to US Coast Guard, it is not clear how close the LED lights – popular because they draw much less current than conventional globes and therefore help batteries last longer – need to be to radio services before they start to cause interference. It has asked boat-makers to let it know if they become aware of the problem in any of their products.

The LED lights are commonly used for navigation lamps, spotlights, and interior and exterior lighting. On some boats, they are also used as visual garnishes.

The US Coast Guard said it knew of at least one incident where the interference from LED lights led to what it said was “a serious safety incident”.

“The maritime recue coordination centre in a United States port was unable to contact a ship that was involved in a traffic separation scheme incident by VHF radio,” the Coast Guard said.

“Other ships have also experienced degradation of theri VHF receivers (including AIS) caused by their LED navigation lights.

It’s also not only the newer radio equipment that is suffering from interference, with LED lighting installed near VHF antennas also found to reduce reception.

One way of testing is to turn on a boat’s VHF radio and adjust the squelch until the audio noise is quiet. If you turn on the LED lights and the radio starts crackling, it is likely they are interfering with the signal.

However, AMSA warned that if the lights interfered with the radio, it could also interfere with AIS.

AMSA has asked boat owners to report any instances of radio interference via reports@amsa.gov.au with details including make and model of LED light, radios affected, distance from the lights to the antenna, and “any other details that would help us understand the nature of the problem”.