Are you running
OpenCPN on Windows?
If so, try installing Franson GPSGate. Using a Bluetooth
GPS without it is a nightmare, because Windows support for the bluetooth
serial port profile is very poor. GPSGate fixes this very neatly and also allows you to share the GPS data with multiple apps (eg. OpenCPN and NavMonPC, any other Nav programs) at the same time.
Regards,
Mike