An AIS (Automatic Identification System) receiver is essentially a black box that plugs into a chart plotter and lets you identify, locate and read important safety data about vessels and aids to navigation broadcasting AIS signals. There are a number of models from Furuno, Garmin, Icom, Raymarine and others. We chose the compact Si-Tex MDA-2 Metadata Dual Channel AIS receiver ($258.99, defender.com), which measures 5½ inches wide by 4 inches high by 1¾ inches deep.
Time to Complete: 4-5 Hours
Tools and Supplies:
* AIS black-box receiver
* VHF antenna and ratchet-mount base
* NMEA 2000 T-connector ($19.95, thegpsstore.com)
* NMEA 2000 backbone cable ($24.95/6½-foot, thegpsstore.com)
* Two-circuit terminal block for NMEA 0183 connection ($3.89, westmarine.com)
* In-line 3-amp fuse
* Marine crimp-on ring terminals and butt connectors
* Cable clamps and tie-wraps
* Wire cutter
* Wire stripper
* Power drill and drill bits
* Socket wrench set
1. Mount the AIS Unit
Choose a location where you can glance at the two indicator lights (green for power, amber for reception) and there’s room to route the NMEA network cable, power/accessory cord and antenna cable. We chose a cabin bulkhead inside the companionway. The unit can be mounted in any position but should be at least 20 inches from any compass. Use the four supplied stainless-steel screws to secure the unit.
2. Install an Antenna
You need a VHF antenna for AIS reception. Companies such as Digital Antenna and Shakespeare offer optimized AIS antennas, but a standard VHF antenna will also work fine. We chose Digital’s 4-foot model 578-SW with 4.5 dB gain ($87.95, starmarinedepot.com), using a ratchet mount to lay it down for low bridges, trailering and storage. Route the cable to the AIS and attach the VHF plug. Go to step 3 or 4.
3. NMEA 2000 Plug-In
Using an NMEA 2000 backbone cable and T-connector is the simplest way to integrate an AIS unit with a chart plotter. Make sure the cable is long enough, and then route it from the AIS receiver to the onboard NMEA network connectors — a series of T-connectors usually located behind the helm. Insert a new T-connector and connect the backbone cable to the T-connector and the NMEA 2000 port on the AIS unit.