AIS stands for Automatic Identification System and that is exactly what it does. When asked about AIS, we often use the example of exchanging virtual boat “business cards" on the water. AIS information includes the vessel name, call sign, vessel size, and navigation data such as present location, course on ground, and speed on ground. AIS information can be used on its own, but most often the information is displayed on your boat’s chartplotter by overlaying each AIS target's physical location, COG, and other information in relation to your position and COG. Some chartplotters will even predict potential collisions and warn the operator. Since AIS information is transmitted over VHF frequencies, it does better than line of sight, and commonly is able to receive AIS broadcasts over low mountains or islands. Unlike radar, AIS can "see" around corners. This can be a huge safety benefit in inclement weather or when navigating the many islands and passes on BC's coast, and it is a great complement to your existing radar. Also, because AIS includes the vessel's MMSI number and name, hailing a particular ship over VHF can be simplified.
A quick note on MMSI numbers, they are like a phone number, a unique identifier for your boat. It should be noted that it's important to properly register your MMSI number. In Canada, when a boat changes hands, you must fill out an application to register the change of ownership with Industry Canada. This ensures that in the case of an emergency, the right people can be contacted as the application includes information on your vessel (useful for the Coast Guard) and emergency contact information. Most recreational boats will use the Annex A Form. If you have radio equipment other than a VHF (ie an SSB or ham radio) or require a radio license, you need to fill out an Annex B Form from the same Industry Canada website.
[INSERT] An MMSI number is required in order for any AIS device to operate as a transmitter.
Class A or Class B? AIS is a fully automated tracking system used to identify and track other vessels visually, as a method of collision avoidance. Passenger ships, such as ferries, tugboats and most large commercial vessels, have a Class A transceiver (12 watts), to send and receive AIS information on VHF frequencies. Each ship transmits a unique identifier (MMSI) and its current coordinates, plus information like navigation status, SOG, COG, the name and size of the vessel, and even at times its destination. Some recreational boaters opt to transmit AIS information using a Class B transceiver (2 watts). AIS information is free and no subscription is required. All you need to take full advantage of AIS is a VHF or AIS antenna and AIS receiver (and/or transceiver), plus a compatible chartplotter or smartphone/tablet.
Warning: There are a number of apps that provide AIS information but they should never be used to make navigational decisions as the navigation information updated on the app might be outdated. Receiving old data is not useful for predicting a potential collision. For an online example of AIS information visit marinetraffic.com.
The Vesper Marine WatchMate XB-8000. Now that you have decided that AIS would be a good addition to your boat, how do you choose? Although most major chartplotter manufacturers have their own AIS components, we recommend Vesper Marine. Based in New Zealand, Vesper’s main business is AIS, they have about 80% market share and they are the best at what they do. The product that we install the most is the WatchMate XB-8000 smartAIS transponder with Wi-Fi and an NMEA 2000 gateway. One of the unique things about this product is that you can use it even if you don’t have a chartplotter. The WatchMate App allows you to monitor navigation data, AIS and GPS alarms from your mobile device over a local Wi-Fi network. The XB-8000 will transmit your position over radio frequencies every 3 minutes when your speed is under 2 knots or every 30 seconds otherwise and your vessel information is transmitted every 6 minutes.
The XB-8000 is compatible with all leading brands of marine equipment and MFD’s including Raymarine, Garmin, Furuno and Simrad. It also has galvanic isolated USB ports which protect your transponder and connected equipment, such as a laptop, from high current. The unit is fully waterproof to the IPx7 rating.
The Vesper WatchMate XB-8000 receiver is small, so it is easy to fit onboard your boat, and is often mounted in a low profile location behind an instrument panel. This makes is easier to interface with your chartplotter and requires minimum wire runs. Remember to write down the Serial Number from the unit before you install it, as this is required to set up the Wi-Fi.
Let’s take a look at the connections required; power, an AIS or VHF antenna and the GPS.
Power - A 2 meter power cable with attached 10 pin plug is supplied with the XB-8000, you may extend this cable if necessary. When attaching the cable ensure you fully engage the locking ring to make a watertight seal. Always use a 2A fuse or circuit breaker, do not connect directly to the battery and if you must extend the power connections, use high quality pre-tinned marine grade wire which is at least 16AWG.
AIS/VHF Antenna or a VHF Antenna with a splitter – The AIS system uses two special “data only” channels in the VHF frequency range so almost any VHF antenna can be used to receive and transmit AIS data. The problem is that both the AIS and the VHF antenna should be installed at the highest point of the boat however, if you choose to install two antennas they must be a minimum of 2 meters apart otherwise all of the 25W power of the VHF will go directly into the AIS receiver and damage it. Therefore, how do you decide whether it is better to install a VHF antenna and an AIS antenna or use an existing VHF antenna with a digital splitter?
As we said before, if you are going to install a dedicated AIS antenna, it must be at least 2 meters from any other radio antenna or vertical metal structure. If there is room on your boat, having two antennas (one VHF and one AIS) is a bonus.
If you would prefer to use your existing VHF antenna, make sure it has a vertical radiator, an antenna gain of 3dB or similar and an impedance of 50ohm. In the past, boaters preferred to install two antennas instead of an antenna and splitter because the reception was compromised on both the VHF and the AIS. That concern has been eliminated with new technology. As far as a digital splitter, we recommend the Vesper SP160 which is designed specifically for use with Vesper Marine AIS transponders. It has connections for AIS, VHF, AM/FM radio and requires an external power source.
The SP160 has a built-in low noise amplifier which greatly improves AIS reception and increased range. It is an active splitter that automatically disconnects the signal to the AIS device if a transmission is detected from the VHF radio. This ensures that the VHF can always transmit even if the power to the splitter fails. Before you choose a splitter, make sure it is compatible with your AIS receiver/transmitter as it may cause irreparable damage.
GPS - The WatchMate XB-8000 ships with its own external 50 channel GPS with WAAS and EGNOS and cannot be used with a third party GPS or NMEA device. This is not unique, Class B AIS transponders are required by international regulations to use their own GPS. That being said, you can use the XB-8000 to provide GPS data to other devices using NMEA 0183, NMEA 2000, USB or Wi-Fi. The GPS antenna must have an unobstructed, clear view of the sky and not be installed too high on your boat. In rolling or confused seas, you will want the GPS lower to the water for the best reception. Do not place the GPS antenna near or in the path of a radar or HF antenna.
[TIP] Use the the WatchMate App to view the satellite signal strengths to determine the best location to mount the GPS antenna.
The antenna cable is terminated with a small SMA connector so that it can be routed through holes and openings. We recommend making the connection to the AIS responder last, after the antenna installation is complete. Do not cut the cable unless you have the proper tools to crimp a new connector.
The Vesper XB-8000 also serves as an NMEA gateway and can translate NMEA 0183 instrument data such as heading, wind, depth, speed and temperature. This allows you to view this data along with GPS and AIS information, simultaneously, on up to five Wi-Fi devices such as smartphones, computers, tablets and even other Wi-Fi routers. Because it consumes very low power it may be left on.
If the XB-8000 detects a risk situation such as a potential collision, anchor drag or person overboard, it will sound an external alarm which operates even if your plotter, MFD or mobile device is turned off. The external alarm and switch can be installed anywhere on the boat, usually next to your chartplotter. It comes with a mute button but can also be muted through the WatchMate app on your smart phone.
If you are a competent DIY’er with basic wiring skills, this should be a 6 – 9 hour installation. AIS is a great safety tool for any boat and works as a good addition to radar alone. The Wi-Fi capability allows everyone onboard to use a smart phone or tablet to follow along on the journey. Combined with the ability to transmit, it allows you to see and be seen.
About the author: Jeff Cote is a systems design engineer and owner of Pacific Yacht Systems, a full service shop delivering marine electrical and navigation solutions for recreational boats. Visit their website and blog for info and articles on marine electrical systems, projects and more: www.pysystems.ca.