I'm not sure about the VV7, but in general, it would be better to use the NMEA2000 network and get 2-way flow of data. The Garmin would get all engine data, including fuel flow. The VV would get GPS data, including speed. That means you could get real time miles per gallon.
My VV4 only had a NMEA 0183 option. As far as I know you can get all the info offered over the SmartCraft interface. I only needed mine for connection to the GPS. I haven't tried to get the SmartCraft data on my plotter, I wanted speed on my VV4 so it would compute MPG. I'll try to remember to see what, if any, data is available to my plotter this spring when the shrink wrap comes off.
Comments
2002 FV 342 on Lake St. Clair - Past Commodore SHC - Vessel Examiner USCGAUX