• 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.

• 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.

• 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.

• 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.

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

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

• 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?