We don't have an electronic chart plotter in our cockpit, as it tends to draw the eye, making you drive the plotter rather than actually looking around to see where you are. However, down below, we have a computer with electronic charts, so we can look at our position if necessary. It really pays to know how accurate a chart is in any particular area. We've seen charts where our little boat icon is ashore or on a reef, when we're actually well positioned in deep water. But this chart of Prickly Bay, Grenada, seems to be spot-on. See where it says "Prickly Bay Marina"? To the left of the text is a black "T" sticking out into the blue water - that's the marina's t-head dock. And see the boat icon at the end of the dock? That's Mr Mac, tied up to the t-head, waiting to fill our water tanks. Now THAT is positional accuracy!