Interfacing Instruments with Navigational Software
B&G manufactures a performance processor, which is a RS232 interface and allows connection of various instruments to a PC. You might check their website.
It is not too difficult to set up if you have some experience cabling boats. You would also need an inverter to power the PC for use underway since most computer batteries do not have sufficient battery strength.
The software for interfacing the instruments is proprietary and available from B&G. Nobletec is charting software, as is Maptec and Maxsea.
Put in a word search for onboard computing and you will get plenty of info.