Steve, when you say "keel area" do you mean just the two wear spots at the bow and stern or are you talking about the entire area under water? Fuzzy Dynel works at the bow and stern (plastic wrap it while it cures) but two layers of the stuff will honestly stick up about 3/32" -1/8" and look like a wet t-shirt unless you coat it with something(paint, graphite/epoxy/aluminum powder). If you want something that will still allow the color of the wood to show through then multible layers of 4oz s-glass strips is very durable. I made a boat with 7 layers tapering from 2" to 1/2" wide just at the bow. I don't think it makes much sense to put a strip of something down the full length of the keel since lots of gouging occurs off-center. Putting some kind of synthetic over the whole hull bottom would be a waste of epoxy,,,I did it once. You could always attach a 12" strip of 3/8" half oval brass ,,,I'm still tempted to carve a recess in the keel ends and epoxy a piece of nylon cord in it.