Catch 22, it was on my Robcraft when I bought it in 2006 and I'm replacing it with a Furuno 1850WD colour plotter. I've only bench-tested the Navman as the boat has not seen water since I've had it

. (it ended up as a long-term rebuilding project). I have no idea of its age but if you want to, I can mail Navman the serial no. and they should shed some light on the year of manufacture. I have the manual in pdf if you wish to browse it. As for the condition; used, not abused.
Cheers