From Gilletarom's website some excellent information on Networking
http://www.plaisance-pratique.com/OpenCPN-Networking-repeater-to
The means :
Setting OpenCPN on the PC server
Setting OpenCPN on PC Receiver
On the server PC On the PC Receiver
..
For this example, all the NMEA data from the GPS and display of AIS data
**On the server PC On the PC Receiver
..
..
NMEA information goes through the RJ45 cable or WiFi and are received on the other PC.
With this application you can have a PC inside and another type tablet outdoors
For more information on OpenCPN Wifi Networking, OpenCPN WiFi network between XP, W7 and W8 tablet, Creation of a network using a batch file see Pratiques et Techniques de la Plaisance