What is the best AIS for a leisure boat?
I'm looking to upgrade my electronics this winter and want to fit an AIS transceiver. There seem to be loads of options ranging from a few hundred quid to over a grand. What is the best AIS to buy for a 38-foot sailing cruiser that crosses the Channel, and do I need a separate antenna for it?
Answer
The best AIS for most leisure boats is a 5-Watt Class B SOTDMA transceiver like the Raymarine AIS700 or Em-trak B954. These modern units transmit your position frequently and with high priority, ensuring you remain visible to commercial shipping in crowded waters.
Why 5W SOTDMA Wins
Older Class B units use CSTDMA (Carrier Sense). This technology transmits at 2 Watts and waits for a gap in commercial Class A traffic before sending your data. In busy shipping lanes like the English Channel, those gaps vanish. Your signal drops out. Modern Class B SOTDMA (Self-Organising) units transmit at 5 Watts and actively reserve their own time slots. They behave exactly like commercial ships.
Do not settle for a 2W CSTDMA unit when buying new. The £150 to £200 saving costs you visibility. Every AIS transceiver requires its own dedicated GPS antenna to meet maritime regulations. You cannot feed it GPS data from your existing NMEA 2000 network. Manufacturers supply most units with a passive GPS mushroom antenna. You must mount this on deck or under a thin fibreglass coachroof.
Best Standalone Transceivers
A standalone black-box transceiver networked to your existing Multi-Function Display (MFD) is the most practical route for most refits. Here are the top performers.
- Raymarine AIS700 (approx. £850): This is the benchmark for most sailing yachts and motor cruisers. It is a 5W SOTDMA unit with a built-in zero-loss VHF antenna splitter. It integrates easily into SeatalkNG and NMEA 2000 networks.
- Digital Yacht AIT5000 (approx. £900): Choose this to push AIS and GPS data to an iPad or tablet. It features a built-in VHF splitter, NMEA 2000, and a dedicated WiFi server that works brilliantly with Navionics.
- Em-trak B954 (approx. £750): Em-trak manufactures the internal transceiver boards for many other well-known marine brands. The B954 gives you 5W SOTDMA, WiFi, Bluetooth, and a splitter in a waterproof casing.
- Digital Yacht AIT2500 (approx. £600): This is a superb 5W SOTDMA option if you lack the budget for WiFi and plan to use a dedicated AIS antenna rather than a splitter.
Premium VHF and AIS Combos
Look at the Garmin Cortex V1 (around £1,600) if you are refitting your entire navigation station and need a new VHF radio. Vesper Marine originally developed this technology before Garmin acquired them. It combines a high-end VHF radio, a 5W SOTDMA AIS, and a remote vessel monitoring system into one central black box.