If you have enabled Over the Horizon AIS on your DataHub but AIS targets are not appearing on your chartplotter, work through the checks below.
1. Check your PredictWind subscription and DataHub account
Over the Horizon AIS requires a PredictWind Professional Forecast subscription.
Make sure your PredictWind Forecast Account has also been successfully validated on your DataHub. Go to Account in the DataHub and confirm that your account and Professional subscription are shown as validated.
For setup instructions, see our Over the Horizon AIS – DataHub Setup Guide.
2. Check that your DataHub is receiving AIS targets
In the DataHub:
Click NMEA.
Select the Syslog tab.
Find AIS Target refresh.
If the AIS Target refresh shows Status: Success, the DataHub is successfully receiving Internet AIS targets.
Check the number of vessels downloaded. This shows how many AIS targets the DataHub is receiving before filtering and publishing the unique targets onto your NMEA2000 network.
If the DataHub is not receiving targets
Make sure the DataHub is receiving GPS data from your NMEA2000 network. If your NMEA2000 network is connected to the DataHub N2K port and your instruments, including your chartplotter and GPS, are powered on:
Go to NMEA > Settings.
Select NMEA2000 on CAN0 as the Source.
Click SAVE & APPLY.
Check that GPS Status changes to Active and that GPS data is being received.
Please allow up to 30 seconds for the status to update.
3. Check your chartplotter compatibility and limitations
Chartplotters and navigation apps can have their own limits on the number or range of AIS targets they display.
From our testing and feedback received from customers using Over the Horizon AIS:
Garmin: Garmin devices have been reported to display AIS targets only within approximately 75 miles. Some Garmin chartplotters may also be incompatible with Over the Horizon AIS because they require NMEA2000 AIS data in a proprietary Garmin format that is unavailable to PredictWind. Your Garmin GPS will work fine for GPS tracking; this may only affect the AIS display.
Furuno and Raymarine Axiom: devices display up to the closest 100 AIS targets from all sources. Chartplotters have a limited CPU capacity, and their software is designed to prioritize and track the nearest targets to avoid collisions, so this is expected.
Raymarine: some Raymarine devices may also require a DataHub Firmware update to display AIS target names correctly.
Navionics: The Navionics App displays only the closest 100 AIS targets from all sources.
OpenCPN: Has been reported to work with Over the Horizon AIS.
TimeZero: Has been reported to work with Over the Horizon AIS, although vessel dimensions may not be displayed.
Chartplotters have limited processing capacity and may automatically prioritize the nearest AIS targets to avoid overloading the system.
4. I know boats are nearby, but they are not showing
Not every vessel can be consistently tracked using satellite AIS.
Many cruising boats use Class B AIS, which may not provide reliable and consistent satellite AIS reception offshore. If you know another boat is nearby but it is not appearing, possible reasons include:
There is no shore-based AIS receiving station within range of the vessel.
The vessel's AIS transmission is not being consistently received by satellite.
If Enable AIS to Internet is enabled on your DataHub, the DataHub can share AIS targets received locally from your boat's AIS receiver with Internet AIS services.
This helps improve the visibility of vessels around DataHub-equipped boats. Once a vessel moves outside the reception range of a DataHub or another AIS receiving station, it may no longer appear until its AIS transmission is received again. Below is a screenshot of a Class B boat showing on the AIS page because a nearby vessel with a DataHub picked up its AIS signal and shared the position via the Internet.
5. Check your Range and Target Age settings
Your Range or Target Age settings may be limiting the targets sent to your chartplotter.
In the DataHub, go to:
NMEA > Internet AIS
Then check Range and Target Age.
Range determines how far from your vessel the DataHub searches for Internet AIS targets. It can be increased to a maximum of 300 miles.
For coastal cruising, a smaller range is generally recommended. Offshore, you may want to use a larger range, depending on your chartplotter's capabilities.
Target Age determines how old an AIS position can be before it is excluded.
The DataHub default is 45 minutes. Internet and satellite-acquired AIS positions may already be some time old when received, so increasing Target Age can help determine whether this setting is excluding the vessels you expect to see.
6. I can see more AIS targets in the PredictWind App than on my chartplotter
Make sure you are comparing targets using similar Target Age settings.
The DataHub default Target Age is 45 minutes, while the PredictWind App can display targets over a considerably longer period. This can make it appear that the PredictWind App is receiving more vessels than your chartplotter.
As a test, set both to 60 minutes and compare the targets again.
In the PredictWind App, go to:
Tools > AIS
In the DataHub, go to:
NMEA > Internet AIS
Then set Target Age to 60 minutes and compare the AIS targets displayed on both devices.
Remember that your chartplotter may still apply its own AIS range or target-number limitations.
Still not seeing AIS targets?
If the DataHub Syslog shows AIS Target refresh: Success and vessels are being downloaded, but no Over the Horizon AIS targets appear on your chartplotter, please contact PredictWind Support.
Please include:
Your chartplotter make and model
Your DataHub serial number
How your DataHub and chartplotter are connected
A screenshot of the AIS Target refresh information from NMEA > Syslog
This information will help us determine whether the issue is with the DataHub settings, NMEA connection, or the chartplotter itself.