New: Live Data from Your Boat via Signal K — How to Set It Up

Your boat is lying in a bay, you are at home — and you have no idea whether the battery is holding up, how hard it is blowing out there, or whether the boat is still where you left it. That is exactly what live data in ClearShip is for.

A free plugin for your on-board Signal K server sends position, course, speed, wind, depth, temperature, pressure and battery state to ClearShip. You see your boat on the map and every instrument reading as a tile — in the browser and in the app, from anywhere.

What you need

Setup in three steps

1. Install the plugin

Open your Signal K server in the browser and go to Appstore. Search for clearship and install ClearShip Telemetry. Restart the server when Signal K asks you to.

Or directly on the server:

cd ~/.signalk
npm install @welytics/clearship-signalk
sudo systemctl restart signalk

2. Create a token in ClearShip

In ClearShip: Boat → Live → Connect boat → Create token.

3. Paste the token into the plugin

Back in your Signal K server: Server → Plugin Config → ClearShip Telemetry. Paste the token, enable the plugin, save.

The plugin status line then reads something like:

Connected — 12 measurements in 1 frame(s) via delta stream

The number of measurements is the figure that matters. If you see a warning instead of a number, the plugin reaches ClearShip fine but finds no data in Signal K — see Troubleshooting.

In ClearShip, the first position appears within a minute.

Which data is transmitted

The plugin reads values two ways, in this order:

1. Full model (app.getSelfPath) — preferred, because the source priorities configured in your Signal K server apply. With several GPS sources on board the position stays stable instead of jumping between antennas.
2. Delta stream — fallback. On some servers the full model returns nothing even though the data is clearly present in the Data Browser (observed on Victron Venus OS). The trade-off: where a path has several sources, last-received wins instead of the configured priority.

The status line names which one is in use: via full model or via delta stream.

Sensors on non-standard paths

Not every sensor publishes to the standard path. A RUUVI tag, for instance, publishes under the location name configured in its own plugin — a tag set up as cabin ends up on environment.cabin.pressure, not environment.outside.pressure, so the plugin would not find it.

Two ways to fix that, either is fine:

1. Map it here. Enter the path under customPaths → Pressure. Unit conversion still applies — Signal K is SI everywhere, so Pa still becomes hPa no matter which path the value came from.
2. Map it in Signal K. Change the sensor plugin's location, or remap the path server-side. Cleaner in the long run, because every other Signal K consumer benefits too — but it changes your vessel's data model.

To find the right path, enable listPaths and restart the plugin. It writes every path it has seen on vessels.self to the log:

All 87 paths seen on vessels.self:
  environment.cabin.humidity = 0.54
  environment.cabin.pressure = 101820
  environment.cabin.temperature = 297.45
  ...

The same information is in the Signal K Data Browser — listPaths is just faster when you already have the log open.

Extra readings: tanks, revolutions, shore power

The built-in fields cover what every boat has. Everything else differs from vessel to vessel, so it is configured rather than hard-coded. Add an entry under customMetrics for each one:

factor and offset exist because Signal K is SI throughout. A tank level arrives as a ratio, so factor: 100 with unit: "%" gives a readable tile; a fridge arrives in Kelvin, so offset: -273.15 with unit: "°C" does. Converting on board rather than in the cloud means the stored value and the displayed value are the same number.

Each reading appears in ClearShip as its own tile the first time it arrives — nothing to configure on our side. A tile exists exactly when a sensor exists: a boat without a wind instrument does not get an empty wind tile.

Adjusting the tiles in ClearShip

Under Boat → Live → Configure live data you set, per boat:

This setting belongs to the boat, not to the browser or the user: the whole crew sees the same tiles, switching devices changes nothing, and the same account can have two completely different instrument panels for two boats. Anyone who may edit the boat may change it.

History

Next to the current value, every tile shows the history for the selected window: 15 minutes, 1 hour, 24 hours or 7 days. Angular values such as course and wind direction get a compass rose instead of a curve — an average of 350° and 10° would come out as 180°, pointing exactly the wrong way.

Privacy, and a dry run before you send anything

If you want to see what the plugin would actually transmit first, enable dryRun. It then builds frames exactly as in normal operation and writes them to the Signal K log — nothing is sent. The warnings are the same as in live operation, so the dry run doubles as the fastest diagnostic.

Troubleshooting

The plugin status line names the cause in almost every case:

Detailed logs live in the Signal K server under Server → Server Log. The plugin additionally logs via debug (DEBUG=clearship-signalk), including a one-off inventory at startup of which expected paths your server does and does not provide.

What this is good for in practice

The real value shows up when you are not on board:

• Winter storage: keep an eye on battery voltage before deep discharge ruins it.
• At anchor: check the wind at the mooring before you take the dinghy back.
• Charter or boatyard: where is the boat right now, and since when?
• With the crew: every member of the boat sees the same live data — nobody has to share credentials.

Availability

Live data is part of the Skipper (1 boat) and Profi (up to 5 boats) plans. The Signal K plugin itself is free and open source (MIT). Switching the connected boat is possible at any time: free up the slot, connect a different boat — the device stays set up and resumes sending as soon as it gets the slot back. Details on the pricing page.