AIS Failure
Raymarine Chartplotter
Severity: ModerateWhat it means
Raymarine 'AIS Failure' (or 'No AIS data' / the AIS triangles disappearing from the chart) means the plotter has stopped receiving the AIS feed.
You're no longer seeing other vessels' AIS positions — and if you run a transponder, others may not be seeing you.
The cause is usually the AIS unit's power, its data connection to the network, or its VHF antenna feed.
Affected Models
- Raymarine Axiom / Axiom Pro paired with AIS650, AIS700, or a third-party receiver
- Raymarine eS / gS Series on a SeaTalkng or NMEA 0183 AIS feed
- Systems where the AIS shares a VHF antenna through a splitter
Common Causes
- AIS unit lost power — separate breaker or fuse popped
- Data cable (SeaTalkng spur or NMEA 0183 pair) loose between the AIS and the plotter
- VHF antenna or antenna splitter fault — AIS powers up but receives nothing
- AIS transponder in silent mode or with no GPS fix of its own (it won't transmit without position)
- NMEA 0183 baud rate mismatch (AIS outputs 38400, plotter port set to 4800)
- Failed AIS receiver
How to Fix It
-
Confirm the AIS unit has power.
Find the AIS receiver or transponder (often tucked behind the helm or in a locker).
Check its status LEDs — most show power, GPS, and RX/TX activity.
No power LED means a tripped breaker or blown fuse on that circuit; sort that first. -
Check the data connection.
If the AIS is on SeaTalkng, reseat its spur connector at the backbone.
If it's on NMEA 0183, check the talker/listener wire pair at the plotter's data port.
For NMEA 0183, also confirm the port is set to 38400 baud (the AIS high-speed rate) — a port left at 4800 won't decode AIS sentences. -
Check the VHF antenna feed.
If the AIS has power and a data link but reports no targets even in busy water, suspect the antenna side.
A dedicated AIS antenna with a corroded connector, or a VHF/AIS splitter that has failed, will leave the receiver deaf.
Reseat the antenna connector; if you use a splitter, check it's powered and passing signal. -
For transponders: check its GPS.
A Class B transponder won't transmit your position if its own GPS has no fix.
Look at the AIS unit's GPS LED or its status page.
A blocked or disconnected AIS GPS antenna means you're invisible to other vessels even though your plotter still shows their targets fine.