2.2.5 • Public • Published


Freeboard-SK is a stateless, multi-station, Openlayers based chart plotter for Signal K for displaying and managing routes, waypoints, notes, alarms, notifications and more from any web enabled device.



Vessel / Chart Display:

Moving map display with:

  • Multiple chart overlay using both of online and locally served charts
  • Built in support (no plugin required) for OpenStreetMap and OpenSeaMap(from Signal K server)
  • North-up / Vessel-up orientation
  • Moving Map / Moving Vessel
  • Vessel Heading / Bearing lines
  • Wind True / Apparent display
  • Closest point of approach

and more.

Charts are sourced from the /resources/charts path on the Signal K server and the following chart types / sources are supported:

  • Image tiles (XYZ)
  • Vector Tiles (MVT / PBF)
  • WMS (Web Map Server)
  • WMTS (Web Map Tile Server)
  • PMTiles (ProtoMap files)


Freeboard-SK supports the creation, editing and deletion of all resource types defined in the Signal K specification that are available under the /resources path.

Routes and Waypoints:

Path(s): /resources/routes, /resources/waypoints

  • Show / Hide Routes & Waypoints
  • Set a Waypoint as a destination
  • Set an active Route
  • Select destination point along an Active Route
  • Create / Edit / Delete Routes
  • Create / Edit / Delete Waypoints
  • Create Waypoint at current vessel position
  • Import Routes and Waypoints from GPX files
  • Attach Notes to Routes & Waypoints

Notes and Regions:

Path(s): /resources/notes, /resources/regions

  • Display Notes and Regions
  • View / Edit Note properties
  • Draw Regions and attach Notes
  • Add / Edit / Delete Notes
  • Attach Notes to Regions


Whilst not specifically defined in the Signal K specification, Freeboard-SK supports the import and display of tracks from GPX files which are available under the /resources/tracks path.

  • Show / Hide Tracks
  • Delete Tracks

Alarms and Notifications:

Freeboard-SK can display alarms (visual and audio) & messages contained in Notification messages transmitted by the Signal K server.

Alarm types supported include:

  • Depth
  • Closest Approach
  • Anchor drag
  • "Buddy" notifications
  • All standard Signal K Alarms (i.e. Man overboard, Sinking, etc.)

Additionally you can raise anchor watch and a number of the standard alarms such as Man overboard, Sinking, etc directly from the user interface.

Freeboard-SK also implements the following API endpoint to accept requests for raising and clearing notifications for Signal K Standard Alarms:


Example: Raise Man overboard alarm (default message):

HTTP PUT 'http://host:port/signalk.v2/api/notifications/mob'

Example: Raise Man overboard alarm (custom message):

HTTP PUT 'http://host:port/signalk.v2/api/notifications/mob' {
    "message": "Man Overboard!"

Example: Clear Man overboard alarm:

HTTP DELETE 'http://host:port/signalk.v2/api/notifications/mob'

Signal K Standard Alarms:

  • mob
  • fire
  • sinking
  • flooding
  • collision
  • grounding
  • listing
  • adrift
  • piracy
  • abandon

Vessel Closest Approach alarm: screen

History Playback

Freeboard-SK supports the Siganl K playback api and can replay recorded time-series data captured on a Signal K server equipped with the signalk-to-infludb plugin.


Freeboard-SK allows you to use your favourite instrumentation app installed on the Signal K server.

Select one or more from the installed applications listed in the settings screen and they will displayed in the instrument panel drawer.

When more than one app is selected you can cycle through them within the instrument panel.

Note: The Instrument Panel app is the default application if no user selection has been made.



To get access to experimental Freeboard-SK features ensure you check the Experimental Features option in Settings.

Checking this option will make these features appear in the user interface.

System Requirements:

Freeboard-SK requires Signal K API Version 2 as it makes use of both the v2 Resources and Course APIs.

If installed on Signal K v1.x.x Freeboard features may not be fully functional!

The following features require that the Signal K server have plugins / providers installed to service the following paths:

  • resources/charts - Ability to view charts.

  • navigation/anchor, notifications/navigation/anchor - Ability to set anchor alarm and display notifications.

  • notifications/environment/depth - Display depth notifications.

  • signalk/v1/playback (Playback API) - Replay of recorded vessel data.

  • vessels/self/track - Display of vessel track stored on server.

  • vessels/self/navigation/course/calcValues - Display of calculated course values such as DTG, XTE, etc.

The following plugins are recommended for the Signal K node server to enable full functionality:

  • @signalk/charts-plugin (Charts provider)
  • signalk-anchoralarm-plugin (anchor alarm settings & notifications)
  • signalk-simple-notifications (depth alarm notifications)
  • @signalk/course-provider (course calculations e.g. XTE, DTG, etc.)


Freeboard-SK is an Angular project.

It is recommended that the Angular CLI be installed globally npm i -g @angular/cli@latest prior to following the steps below.

  1. Clone this repository.

  2. Run npm i to install project dependencies. Note: this will also build the project placing the deployable application files in the public folder.

  3. Run npm start or ng serve to start a development web server and then navigate to http://localhost:4200/ to load the application. The application will automatically reload once you save changes to any of the source files.


The Freeboard-SK application will look to connect to a Signal K server at the ip address:port contained in the url of your browser.

In development mode you are able to specify the Signal K server host address and port you wish to connect to by editing the DEV_SERVER object in the src/app.info.ts file.

    host: '', 
    port; 3000, 
    ssl: false 

Note: These settings apply in Development Mode only!

npm start
ng serve 
ng build

They will NOT apply when using Production Mode, the generated application will attempt to connect to a Signal K api / stream on the hosting server.

ng build -c production
npm run build:web

Building a Release:

Building the Application:

To build all components of the application ready for release use the npm run build:all command.

Building individual components:

  • To build only the web application use the npm run build:web command.
  • To build only the helper plugin use the npm run build:helper command.

Built files for deployment are placed in the following folders:

  • /public (web application)
  • /plugin (helper plugin)

Building NPM package:

To build the NPM package use npm pack command which will:

  1. Execute npm run build:all
  2. Create the NPM package (.tgz) file in the root folder of the project.

Freeboard-SK is a port of http://www.42.co.nz/freeboard for use with Signal K communication protocols and server features.

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  • timmathews
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