Dave, why do you want to add Kevlar? If it's for abrasion a layer of 4oz s-glass will be a lot easier to add,fair in and repair for very little weight. Two layers would be truly overkill. A layer of 6oz e-glass would be cheap and easy. The tensile qualities of kevlar are best utilized on the inside and its wonderful abrasive qualities leave fuzzy fibers that stand up when repairing or attempting to fair in on the edges. I'm embarassed to say I glassed the outside of a Pygmy 13 with 6oz s-glass with another layer of 6oz on the bottom panels with the idea that someone might use it for landing on rocks one day,,or dropping off of vans. It's been tied onto metal canoe racks, against plastic boats with sand in between, and sat in on asphalt with no problems. On a larger kayak I doubled the bottom with two layers of 4oz s-glass, it's been used A LOT with no breaks into the wood.