How to enable Over the Horizon AIS

To enable this requires the following:

To update your DataHub Firmware, please read this help article.

To enable this feature smoothly, your DataHub requires a high-speed Internet connection, e.g. Starlink, Wi-Fi Hotspot, 4G Router or USB Tether. Please check on the Internet Status page, WAN Interfaces, that at least one box is coloured GREEN with Status: Active.

Upon reloading the DataHub with 4.0 Firmware or later, the initial landing page of the DataHub will be the Account Page to enter your PredictWind Forecast account username and password.

Please add your account username and password, then click SAVE & APPLY. You will be returned to the Internet Status page if your account has been validated successfully.

Click the top menu Account, and you will see your subscription level validated:

GO exec / Offshore Set up only - If you only have a GO exec connection available, so no other high-speed Internet is possible, please tick FORCE SETTINGS above to skip credential validation before you save. If your credentials are correct, enabling your Account will work when the GO exec next polls tracking. If your credentials fail, this page will update to Status: Invalid.

Next, click on the NMEA menu, then Internet AIS. Then click and enable these settings:

Click Save & Apply.

Enable AIS to Internet - this sends your position and details, and any boats shared by your AIS receiver, with Internet aggregators to maximize your visibility and that of the boats around you.

Iridium GO — for each of AIS To Internet and AIS From Internet, this setting allows the DataHub to route AIS messages via your Iridium GO exec.

Enable AIS From Internet - this enables Over the Horizon AIS from Ethernet WAN, 2.4GHz Wi-Fi, USB tethered Internet connections, and Iridium devices if the Iridium setting is also enabled.

Use GPS - centres the query of the request AIS targets based on your GPS position. If you do not tick this, please manually enter a Lat/Long to receive boats within the range of that position. The GPS used is your NMEA, with a fallover to DataHub Internal GPS if enabled.

Mark AIS - this marks up received AIS positions with "DataHub", allowing you to easily differentiate those vessels received via your AIS transponder and those obtained via the DataHub.

Tag AIS - this marks up received AIS positions with "Internet", allowing navigation Apps to differentiate these vessels from those acquired over VHF.

By default, leaving the Range and Target Age at 25 miles and 45 minutes is recommended to avoid overwhelming your chartplotter or consuming excessive satellite data.

Range can be increased to a maximum of 300 miles. With time, you will learn what works for coastal cruising vs. offshore. When coastal, a smaller Range setting is recommended. When offshore, a more extended range is suggested; however, it's worth considering your speed and time to encounter a vessel located and your chart plotter's maximum supported settings. Garmin chartplotters will only display vessels within a 75-mile range and Furuno charplotters may only display up to 100 AIS targets.

As a general guide, 1000 vessels, updated hourly, would transfer approximately 307kb daily. 5000 vessels would transfer ~64kb of data via a GO exec on a 15-minute polling interval; this equals 6.14 MB per day. In practice, the data usage should be considerably less, with fewer surrounding boats, the default settings, and hourly updates.

Target Age can be increased unlimited or reduced to 0 to display all targets irrespective of acquisition time. The default of 45 minutes is based on Internet satellite-acquired targets being up to 30 minutes old and a polling interval of 15 minutes between AIS target collection sessions.

From DataHub Firmware version 4.08 onwards, two new settings have been added which allow you to restrict the DataHub to publish AIS targets over NMEA0183 only and set a maximum number of targets the DataHub published over NMEA2000 and 0183.

NMEA0183 only - Transmits AIS data over NMEA0183 via Wi-Fi and Ethernet LAN. The DataHub will not place targets on the NMEA2000 bus. This setting prevents older Chartplotters / MFDs, that cannot handle many AIS targets, from being overwhelmed. Tablet, PC, and mobile navigation apps will still receive AIS data. This also reduces the load on the NMEA2000 bus.

Max Targets - Limits Internet-acquired AIS targets to the nearest Max Targets number of vessels. Leave blank to display ALL targets. This setting does not limit the number of AIS targets downloaded within the set Range and Target Age. However, it does set the DataHub to sort and publish only the closest targets up to the maximum target value.

Congratulations! You've now enabled Over the Horizon AIS on the DataHub. The DataHub will request and receive it via your Internet connection and share this via NMEA2000 and NMEA0183 through DataHub Wi-Fi. An example of Over the Horizon AIS displaying in OpenCPN from a land-based DataHub is below.

Please allow some time for targets to be acquired and presented in your charplotter or navigation app. Your first targets should appear within 1-2 minutes of the next update; however, new vessels may continue to appear for up to 45 minutes. The DataHub will only ever add to AIS targets on your network. If you notice duplicate targets, please allow some time for this to self-correct.

If your chartplotter is connected via NMEA2000 to the DataHub, the data stream will start automatically with the next update the DataHub receives, shared on the N2K bus network.

Software navigation apps such as AquaMaps, OpenCPN, or Navionics require your device, e.g., laptop, iPad, or tablet, to be connected to DataHub Wi-Fi and their source for NMEA data to be set to the DataHub. Please see this article for specific instructions to connect your navigation app.

Important Note: If you see your own vessel appearing as an AIS target and it is setting off proximity alarms, this is due to your VHF AIS not publishing itself as a target on the N2K bus, so your vessel is downloaded and displayed by Over the Horizon AIS as a target. Please see this troubleshooting step to resolve it.

Over the Horizon AIS is a fantastic new feature many customers are starting to use. We're hearing great stories about their experiences, including their feedback and many questions. We have summarized the common questions and answers in our Over the Horizon AIS - Frequently Asked Questions.