I lost my Garman E-Map to a fire in my garage and upgrade through insurance to a Map 76S. I did spend the money on the blue chart. I haven't used it a hole lot yet, but besides it being totally water proof, having the tides built into the unit is way cool. Whether your in the san juans, puget sound or even canada, it will search for the closest tide station and give you the tides and plot on the tide curve where you are depending on what time of day it is.