Don, I was just thinking for Brandons expected tripping in Baja that a flat black hull might be one heck of a solar collector laying upside down in the sun. Kevlar is very abrasion resistant but fuzzes up a whole bunch thereby making repairs a bit unsightly. From a structural standpoint its better to have a material with a higher compressive strength (like glass) on the outside. S-glass has better abrasion than e-glass but comes close to Kevlar in cost. With all the other materials out there it usually comes out to be cheaper and lighter to just add another layer of glass while being frugal with the epoxy. I put polyester cloth on top of a layer of 4oz for the hull covering of a kayak but the 5oz polyester soaked up about as much resin as 7-9oz glass. I think it makes more sense to put it (whatever) where it's needed than to just put on some fancy materials everywhere.