What you want is available, but I hope you have deep pockets ... to handle the where you were vs. where you're going, FLS (forward looking sonar) is available from several mfg also (for even more $$) ... as for mapping/marking ... Lowrance has sonar/chartplotter combos with WAAS ... if your reservoir isn't on an electronic chart, you could always hand plot it (hit mark for every thin water rock and plot it later by hand) ...of course you still need a real bathy chart of the lake/reservoir ... Check out Humminbird and Garmin as well ... and keep this in mind: plotters using Navionics electronics charts have access to a 8,000-and growing lake database don;t know if your is on it, but ... not sure what freshwater coverage Garmin Blue Charts have ...

hey ... maybe - if the reservoir HASN'T been bathy'd you could get a grant to do so ...

Good luck or keep the boards up!

gary