The area between Savannah and Fernandina is highly 'variable' on Garmin Plotters. Use your 'eyeballs' on the physical daymarks in preference to blindly following 'the magenta line' - especially south of Brunswick and near Jekyll Island and north of the St. Marys River. The waterway 'behind' Jekyll remains 'very thin' and the magenta line is 'off'; so search with your depth sounder while watching the daymarks to find the deepest water.