I'm looking at getting the Navionics Map Pack for my Humminbird 798 c. Getting all the different lakes it includes is nice, but the majority of my fishing is done on the Potomac so I am most concerned how Navionics does the Potomac. It is listed under "Maryland." It doesn't specify if it is just the Upper Potomac or also the tidal Potomac (what I fish). I just want to be sure they don't consider the tidal area 'coastal' or something.  Any nova guys out there with any insight on this? If you have it, what are your opinions? Thanks guys, I want to get it and mark a bunch of spots over break if the fishin aint too hot. It'll be a good way to fight the cabin fever

i would love to figure this out as well. i have the 788 ci unit with hotmaps premium and gold maps. They both do well on the river but would love to know if there is a better map for the river.

I wish I had some insight on this topic. I bought a 798 pre loaded with the navionics bundle package a few months ago but its still sitting in the box till I install it in a few months. Im curious tho how its gonna do on the potomac. Altho once I move next summer imma be fishing the potomac less and central va spots more.

Hmm well once finals are over on Thursday I'll do some google searches and see if I can't uncover something else.  I'll keep you guys posted, if you discover anything let me know. 

I think you have to buy a special marine chart for tidal waters. See http://www.navionics.com/Charts_GoldPlus.asp?ChartSizeID=8&GoldCode=16XG-2

The Hotmaps Premium East has the same contours and spot soundings as the GMCO paper maps of the Potomac and Chesapeake Bay. I have the 2006 and 2009 editions and also have the Hotmaps Explorer on my laptop. I Just checked the 2009 edition and it shows contours out to about 10 miles off the coast at some zoom levels

The Hotmaps Premium East has the same contours and spot soundings as the GMCO paper maps of the Potomac and Chesapeake Bay. I have the 2006 and 2009 editions and also have the Hotmaps Explorer on my laptop. I Just checked the 2009 edition and it shows contours out to about 10 miles off the coast at some zoom levels

Thanks for clearing that up Wayne.  Thats what I was curious about.  Looks like I won't be getting anything more detailed with Navionics that I don't already have with GMCO, but I'll have the ability to mark spots with my GPS which will be nice

Any GPS unit with a plotter screen can be used to save waypoints, trails, and routes. The map software just overlays the maps on the plotter screen. The Humminbird units have a basic background map and the Lowrance handheld H2O has a background map also, some other units may have it included too.

I have an old Eagle handheld that is just a plotter with no map capability and it will get me from point A to B and back just as well as the newer units.

Any GPS unit with a plotter screen can be used to save waypoints, trails, and routes. The map software just overlays the maps on the plotter screen. The Humminbird units have a basic background map and the Lowrance handheld H2O has a background map also, some other units may have it included too.

I have an old Eagle handheld that is just a plotter with no map capability and it will get me from point A to B and back just as well as the newer units.

True, I just don't find the Humminbird background map all that helpful.  I guess its better than nothing