Well since the origial budget is 600, this looks good:I like the Lowrance Elite series plotters if one is looking for a standalone plotter or plotter/depth combo- great value for the money, especially pre-loaded with navionics charts- it saves a substantial amount of cash.
Lowrance Elite-5m HD Gold Chartplotter
I know, it is only NMEA 0183, but if you are looking for a capable standalone, not trying to link it to the rest of your electronics suite, it is more than enough.
I have had one aboard for 5 seasons, and have zero complaints.
two.Connect your Navman NMEA Out (+) to the Autohelm NMEA In (+). Connect the NMEA Out (-) on the GPS to the electrical (-) of the autopilot, (NOT the NMEA (-)). Configure your GPS to talk NMEA 183. Set a course on your GPS, Sail that course. Hit (Track) on the Autopilot. Watch out for other boats. Good luck Steve Alchemist #909 p.s. The Raynav ST-4000 manual tells you all of this. You may need to cousult the Navman manual for the colors of the wires. It will be fun finding the right size terminals to connect the