NMEA 0183 output is available from the Garmin GPSMAP 478, according to Garmin's product specs on their web site; so, you should be able to use the Garmin GPSMAP 478 for real-time tracking with Offshore Navigator, Offshore Navigator Lite, Chart Navigator Pro, or Chart Navigator Lite.
The Chart Navigator Viewer, available as a free download at http://www.freeboatingcharts.com does not have the real-time tracking feature, but is useful for route planning and chart viewing.
If you are using Chart Navigator Viewer to do route planning, there are many Garmin models that can be used to transfer routes. The list of compatible GPS models is at: http://www.maptech.com/support/doc.cfm?docid=247&plid=24 The Setup Interface in the Garmin GPS needs to be set for Garmin in/Garmin out, not NMEA in/NMEA out, in order to do route transfers.
The Garmin GPSMAP 478 is not on the current list of compatible Garmin models; so, route planning using the Garmin GPSMAP 478 with Chart Navigator Viewer is probably not feasible. You can try selecting different Garmin models in the Chart Navigator Viewer GPS setup, but this would be a process of trial and error, with no guarantee of success. If you try this and find a compatible setting, please let Maptech know, so that the GPS compatibility list can be updated.