Can i use this device in my new boat to monitor tach, speed, batteries (3) and gas level?

maybe have 2 screens. the first one whould show tach, speed and fuel. the second one would show 3 batteries voltages?
Although a little (o.k., a lot) more expensive, you could look into Chetcodigital for ...

Just thought I'd suggest that you start a gallery for how people have their GX's in their PC's and any screen designs they might have.....unless you'd rather it just be included in the "general" Gallery.
(P.S. Hey there Ray and Henry )