Zippy, Kirt here with Navionics. The Gold card does not lots detail in some bodies of water, it comes with what we call Nautical Charts ok in some places not so great in others. What you want is Navionics+ Preloaded it will say this on the package. It covers all of US and Canada with the Nautical Charts or Gold layer similar to what you are seeing now, what you then do is download the high def SonarChart layer for areas that you frequent to the Navionics+ card. To preview the 2 layers go to the Web App its out map preview system. Zoom in and click on the Sonar Icon on the lower left here you can see the difference between the 2 layers of mapping.
The reason they dont have the SonarChart layer on the card for the entire US and Canada is the card can't hold all the SOnarCHart data for all of US and Canada so you or download it to the card. Very easy process it walk you thru the steps when you plug the card into a computer.
Link to the Web App https://webapp.navionics.com/?lang=e...%7B%7CkoGfinxP
Now if you own a Gold card you can upgrade to Navionics+ by buying the Navionics Updates for 99.00 vs 199.00 for Nav+. Nav Updates allows you to upgrade your Gold to Nav+, there is one extra step involved when registering your card online.
BTW these cards go or cover 30 miles of shore
Kirt
Navionics Marine Specilaist