Feb 2018 - Freeboard is very old now, and superceeded by Signal K and its associated apps and devices. This remains as a reference as there is quite a lot of useful technical and other info


  • minimal cost
  • maximum interoperability
  • support wind, log, autopilot, charts, and other common uses.
  • use low cost commodity hardware
  • support modern devices (PC, tablets, cellphones)
  • support for many simultaneous users
  • total system cost (less clients) <USD500
  • use common KAP/BSB or ENC map formats (US NOAA Raster charts work) See OpenSeaMap.org
  • Support Signal K

Thats achieved in a totally unique way, by providing the instruments and chartplotter via a web page over a local wifi link on your boat, so that any device with a web browser can access them.


Like a PC, Freeboard can do many different things for different needs.

  • Multiplex NMEA, convert Seatalk to NMEA and vice versa
  • Broadcast NMEA over Wifi. (eg to OpenCPN, default tcp port is 5555)
  • Provide a low cost way way to add wind instruments, digital compass, or GPS,  via NMEA to existing systems.
  • Use your existing instruments NMEA output, if its available
  • Provide a chartplotter and virtual instruments over wifi to several tablets, PC's or cellphones, all at once
  • Provide low cost autopilot
  • all of the above  at once


There are two major parts to a FreeBoard installation. Both these items are commodity hardware, with a combined cost of about USD100. Even with all the extras (anemometer, motor driver, cases etc) the cost should not exceed USD500. The combination uses a total of about 0.4Amps at 12V so its easy on the battery.

1 - FreeBoardPLC - Arduino

Freeboard runs on the Arduino to interface with boat hardware. It currently multiplexes NMEA-0183, Seatalk, Peet Bros wind sensors and misc hardware, GPS, and  IMU (rate adjusted compass). It provides anchor watch, and alarm functionality, and can control an autopilot servo unit via an extermal motor driver.

Output is NMEA-0183, so it can also be used to provide NMEA to an existing system.

2 - FreeBoard-server - Raspberry Pi.

Freeboard runs on the Raspberry Pi to collect and process data from FreeBoard Arduino, and to provide it via a webserver. Input is NMEA-0183. Output is viewable on any reasonably modern web browser, on PCs, tablets, or cellphones. It supports many concurrent users, so you can finally afford instruments at the helm, the nav station, and in your bunk (for offwatch!).

FreeBoard-server is a java application and can run on any with java, eg PC, laptop, etc.