Welcome to our site! EDAboard.com is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.
I don’t know if this is to simple but there is NMEA for instruments used in smaller boats, like sailing boats and stuff, simple RS232 only. There is also a new standard called NMEA2000 that builds on then can network, but it is not that much used yet.
Search the net, should be a lot of pages describing them.