Download the encoding guide

AIS is a valuable navigation safety radio communication tool. However, its effectiveness is undermined by the broadcast of inaccurate, improper or outdated data.

According to Jorge Arroya, the Program & Management Analyst at U.S. Coast Guard (USCG), 50% of AIS transponders are transmitting data with errors. He says, "Incorrect AIS data is a navigational hazard which could result in accidents or extend the response time of assets during search and rescue operations."

The USCG has published a Guide to assist proper encoding of an AIS system used in US navigable waters. It covers guidelines for encoding your transponder and includes MMSI, vessel name, callsign, type of vessel and GPS antenna position in meters.

There are different ways you can encode and edit AIS details on your Vesper Marine transponder:

  • Using your smartphone or tablet and the WatchMate app (for smartAIS transponders XB-8000 and Vision2
  • Onscreen menu (for transponders with built-in displays like Vision2 and 850)
  • vmAIS (all Vesper Marine transponders)
  • Class B AIS users buying transponders in the US are required to have their MMSI programmed through a licensed marine electronics dealer or installer. Owners should confirm the information and may make their own corrections to the name, callsign, and other details.

    According to the USCG, continual failure to transmit accurately may prompt civil penalty action. Boaters are urged to ensure their AIS data is up-to-date and setup according to this guide. USCG has also published a website which tells you if your transponder is transmitting with errors.



    US Coast Guard