OpenCPN is a free open-source chartplotter and Marine GPS Navigation System, developed by a team of active sailors.

There are many thousands of sailors using this software, and many using GPS2IP as a GPS for the system in many parts of the world.
GPS2IP can provide the navigation data, and connect wirelessly with OpenCPN.
OpenCPN has a different visual look on different systems (mac, PC, etc), but the options should all be the same as outlined below.
If there are major differences, get in touch, or check out the OpenCPN forums.

Figure out your network settings

Normally, you would have your iPhone or iPad on the same network as your computer running OpenCPN, connected over wi-fi.
You can select which network interface you are using on the main GPS2IP page (in the Network Selection section).
OpenCPN can accept GPS2IP data when configured in Socket mode.

It is important that you know the IP address of your iOS device, in order to configure OpenCPN correctly.
You can check the IP address by selecting Wifi IP under Network Selection in the settings, and hitting the little .

For our example, we will assume an IP address of

Select which port to open

OpenCPN needs to connect to a 'port' - it is not normally important what number you use - the default GPS2IP one should be fine.

GPS2IP acts as a 'socket' to OpenCPN, so you must select Socket under Connection Method in the settings.
To check (or change if necessary!), hit the little next to Socket.

For our example, we will assume an port number of 1112.

Configure OpenCPN

Now it's time to make the connection in OpenCpn..
It is recommended to be running the latest version of OpenCPN to ensure optimal performace and stability.

  1. Go into the OpenCPN Preferences/Options window
  2. Select the Connections tab
  3. (While setting up the connection, it is informative to enable Show NMEA Debug Window. You can disable this later)
  4. Hit the Add connection button
  5. Select Network - not Serial
  6. Protocol should be TCP
  7. Address should be your iOS device IP address (in this example, it is
  8. DataPort should be the port selected in the Socket GPS2IP settings (in my case 1112)
    This is how my settings look at this point:
  9. Hit Apply or OK on the OpenCPN settings page


If you have good GPS reception, you should be able to enable GPS2IP, and see NMEA data in the debug Window of OpenCPN.
This is what I'm getting:
Debug Window
(The IP address and port show this is the the currect iOS device - they are the same details that I have just entered)

If the data is coming through ok - your position should be displayed on the main chart.
If there is no NMEA data in the debug window - you'll have to investigate further.


Get in touch, or check out the OpenCPN forums.