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Document status: Early ideas, subject to change.

Project Goals

  • Build a system which allows sending messages between boats which may not be within direct radio communication distance of each other.
  • Allow human written text messages and telemetry.
  • Suitable for small yachts and pleasure fishing boats.
  • Low power usage.
  • Affordable and easy to install.
  • Independent operation: Does not require other infrastructure, central servers, or subscriptions.
  • Open source design.
  • Licence exempt preferably everywhere, initially being developed in/for UK and Canada.

To be implemented with a LoRa mesh network.

Purpose and applications of the system

  • Wind reports from the next fjord / around the corner.
  • Chatting to your friend on another boat (around corner / out of VHF range?).
  • Race tracking.
  • Weather reporting and forecasting. Local forecasts of remote ocean race areas.
  • Checking on your boat when you are away for a long time. Theft detection / recovery.
  • Storm / high seas / anchor alarms.

Onboard Device Specification

  • Small, discrete device that can be installed behind a panel.
  • Minimal UI (probably LEDs and a button or two).
  • Configuration method to set some of: boat name, boat type, ID, network settings.
  • “Low power”. For monitoring a boat left for the winter: can send occasional position reports or alerts using a typical boat lead acid battery for at least six months to a year without causing problems. May use more power when boat is actively in use / has a battery charging source.
  • Runs on nominal 12V boat power, own wiring or from CAN bus.
  • Battery monitoring. At least report supply voltage.
  • Reduce power usage when battery low. Avoid damaging battery.
  • Builtin GPS receiver and antenna.
  • 9 DoF IMU, to detect movement (security), report sea state…
  • Configurable alarms - e.g. movement or voltage triggered.
  • Data logging: There should be some non-volatile storage, useful for weather reports and buffering messages.
  • At least somewhat waterproof case.
  • Possibly: External enclosure for rail mounting on metal boats.
  • Possibly: Builtin battery. Important for tracking if boat stolen and power is disconnected.


  • Wind instrument interface for sensors that may be supplied with the device - probably NMEA0183, NMEA2000, or RS485. Possibly wireless or wired analogue for cheaper sensors.
  • NMEA receive interface for GPS (needed if cannot be installed where internal GPS works).
  • LoRa antenna socket? (I think needed for the same reason, if installed below decks on a metal boat)
  • NMEA receive interface for other boat instruments: wind, depth, compass, IMU, temperatures, tanks, …
  • For the UI: Probably bluetooth to a phone app, or wifi to a computer / web interface.
  • Other sensors, e.g. air quality, humidity, fog, CO2, intruder alarm system. Possibly serial (CAN, RS485) or wifi / IP.


  • Display own and other boats' sensor readings on a map.
  • Send and receive text messages.

Other Possible Devices

Base Station

  • Connects to LoRa network.
  • External antennas
  • Internet linking with ethernet or wifi
  • Mains power
  • Doesn't need NMEA / boat network interfaces. Maybe connects to weather station though.

Panel mount UI

  • Could be like navtex with weather reports, or a map.
  • Text messages.
  • Maybe keyboard or touchscreen.

Portable radio

For monitoring an anchored boat when you are ashore. Take with you in dinghy.

LoRa Network Design

  • Messages should be forwarded between boats to extend range
  • Store and forward possible to allow boats to carry messages to another area.
  • Possible optimisation: replace older messages with new versions
  • Broadcasts. Geographically limited?
  • Addressable messages (maybe not needed at first, ie for simplicity treat everything as public broadcast)


  • Use of satellites to extend range?
nyan/goals.txt · Last modified: 2023/12/11 11:44 by river

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