That is the link to the SAS Planet repository, I encourage you to try it. I ran across it while trying to find a way to put aerial overlays on my humminbird and you bring up imagery from many different sources with just a click. The ArcGis hybrid overlay has a lot of detail around steinhatchee, its not as clear around St Marks. If you have questions just ask, the help site is in Russian so its kind of a pain to use.
Unzip the zip file and run sasplanet.exe

Click here and change this to internet

Click the magnifying glass and search OSM for the town nearest to the area you want to search, the bar on the left controls the zoom or the wheel on your mouse will do the same

This is google earth imagery:

You can change the map here, I prefer the ArcGis Imagery
