AIS Transponder Installation
An AIS transponder lets other vessels see your boat on their plotter and lets you see theirs. We fit Class B transceivers at your berth between Brighton and Southampton: the unit, its power supply, a GPS antenna, the VHF aerial arrangement and the data link to your chartplotter, with a written quote agreed before anything is drilled.
Receive-only AIS shows you the traffic. A transponder transmits too, so ships and other yachts see your position, course and speed. For leisure boats the usual choice is a Class B transceiver, which is designed for smaller craft and sits alongside the existing navigation electronics rather than replacing them.
The box itself is the easy part. A tidy, reliable installation depends on where the antennas go, how the unit shares or separates from the VHF aerial, how it is fused and how its data reaches the plotter. Those choices are what we plan with you.
What a Class B AIS installation involves
Most installations follow the same chain. The transceiver is mounted somewhere dry and accessible, with a protected supply from the DC panel. It needs its own GPS position source, normally a small external antenna with a clear view of the sky. It needs a VHF antenna, either a dedicated one or a shared masthead aerial through a splitter. Finally its output is connected to the chartplotter, usually over NMEA 2000 or NMEA 0183, so targets appear on screen.
- Transceiver mounted clear of bilge water and heat
- Fused supply sized to the unit's draw
- GPS antenna placed for an unobstructed sky view
- Dedicated VHF antenna or an AIS-compatible splitter
- NMEA 2000 or 0183 data to the plotter, then a live check of targets
Sharing the VHF antenna or fitting a second one
A splitter lets the radio and the transponder use the masthead aerial, which gives the best range and avoids a second cable up the mast. The trade-off is one more component in the radio path, so the splitter needs to be a proper AIS type and the coax and connectors in good order. A separate antenna on a pushpit or arch is simpler to fit and keeps the two systems independent, at the cost of lower height. On older boats we often test the existing coax first, because a tired cable affects the radio and the AIS together.
Getting AIS targets onto the plotter
If the boat already has an NMEA 2000 backbone, the transponder normally joins it with a drop cable and the plotter picks it up. Older systems may use NMEA 0183, which needs the correct baud rate and wiring polarity. Mixed networks with Raymarine or Garmin displays are common, and we check that targets, your own vessel data and any alarms appear where you expect them before we leave.
Marine electronics installation · Raymarine installation · Garmin marine installation
Programming, licensing and the MMSI
A transmitting AIS unit carries your vessel's MMSI and details. In the UK that number comes from your Ship Radio Licence, so it is worth sorting the licence before the installation day. Some units are programmed by the supplier and some can be set once only, so we confirm the details with you before entering them.
Busy Solent water and why position matters
Between Portsmouth Harbour and Southampton Water, leisure boats share the channel with ferries, commercial shipping and cruise traffic. That is where being seen on another vessel's screen earns its keep. A good install is one where the GPS fix is steady, the VHF path is sound and the unit is powered whenever the instruments are.
Frequently asked questions
What is an AIS transponder?
It is a radio unit that both receives and transmits Automatic Identification System data, so your boat appears on other vessels' screens and theirs appear on yours. A receiver alone only shows traffic.
What is a Class B AIS transponder?
Class B is the version intended for leisure and smaller craft. It transmits less often and at lower power than the Class A units ships carry, and is the usual choice for yachts and motor boats.
How much does AIS installation cost?
It depends on the unit, whether the VHF aerial is shared or a second antenna is fitted, and how the data reaches the plotter. We look at the boat and give a written, itemised quote rather than a set price.
Does an AIS transponder need a SIM card?
No. Ship-to-ship AIS works over VHF radio and needs no SIM. Some units add optional mobile or Wi-Fi features, but those are separate from the AIS itself.
Can you fit an AIS unit I have already bought?
Yes. Send us the make and model, and we will check it suits the boat's antennas and network before fitting.
Plan an AIS installation
Tell us the boat, the plotter fitted and where it is berthed, and we will come back with a written quote.