(Last update : April, 30th 2020)
Connecting an AIS to a tablet like the iPad provides a very secure anti-collision function, especially since the portability of the tablet makes it easier to be on watch everywhere on the boat.
The Automatic Identification System is a means of communication between vessels using the VHF channel and allowing important information to be exchanged to avoid collisions. Mandatory on large commercial vessels, it is increasingly extending to yachting as a result of equipment cost reductions.
The AIS allows to receive from the surrounding ships:
- Their name and characteristics: MMSI code, dimensions, manoeuvrability, ship category, destination, etc.)
- Their course: course and speed over ground.
The information is presented graphically, with each ship appearing with a logo, a name tag, and its course - a bit like what we know in air traffic control!
This information makes it possible to calculate the risk of collision and to program alarms based on two parameters:
- CPA : Closest Point of Approach = nearest crossing distance between the two vessels
- TCPA : Time to Closest Point of Approach = time remaining before reaching the position of the nearest crossing
CPA and TCPA in Weather4D Routing & Navigation with prediction of closest location
Although it has an equivalent purpose, i.e. to identify surrounding obstacles, AIS should not be mistaken for a radar. Each of these equipments has its own advantages and disadvantages, the ideal being of course to combine both!
|Pros||Low power consumption|
Reduced cost (about 200 to 300€ for a simple receiver)
Provides easily usable information about other boats and collision risks
|See all surrounding obstacles (boats, coast etc.)|
|Cons||Only detects boats equipped with AIS||Power consumption|
Does not provide information on the name and course of the boats
Complex assembly, rather reserved for large units
Pour les petites unités à la recherche d'une solution de détection à moindre coût, l'AIS offre une alternative très intéressante au radar, et rendra de grands services pour la navigation maritime dans des zones de fort trafic ou pour le passage de rails par exemple !
Installing an AIS receiver is already reassuring because it allows you to see the traffic around you. But be careful, you will not be detected by other ships. To do this, you must choose a transponder that transmits your position. Providing yourself with a transponder increases your own safety (more chance of being seen) and contributes to the overall "ecosystem" of AIS (which would be of no interest if there were only receivers and no transmitters!)
Historically prices have been quite high, but we are beginning to see affordable AIS transponders with wifi coming onto the market. Another solution is to connect a wired AIS transponder to a Wifi multiplexer such as the Miniplex-3wi (see below).
There are many AIS receivers or transponders on the market, which generally provide their data in NMEA 0183 or 2000 wired format.
To receive this data on the iPad or an Android tablet, you must first convert it to WiFi.
-> If you already have an AIS receiver in your boat (stand-alone or integrated into your VHF), you can use a NMEA->WiFi converter such as the Miniplex-3wi.
-> If you don't have an AIS yet, you can opt for a device that natively integrates wifi, such as Digital Yacht's iAIS (simple receiver) or Vesper Marine's XB-8000 (transponder), which is very easy to install, and integrates GPS and NMEA0183/2000 connectivity for the other instruments. You can also check the Nomad by Digital Yacht, a wifi transponder which is very easy to install and can be powered from USB!
Once the AIS signal has been received on iPad, it still needs to be displayed! To do this, you will have the choice between a "radar-like" display or a representation on the marine chart.
Among the "radar" applications, iAIS (free) is quite complete and even allows to overlay AIS information on a Navionics map background. Be careful however, this does not make it a real navigation app and it doesn't manage anti-collision warnings.
For full integration on a nautical chart and alerts management, there are more and more navigation applications available, including Weather4D Routing and Navigation, Sailgrib WR, iNavX, SeaIQ and iSailor.
AIS targets viewed in iNavX