James and I rasped, sanded and scuffed the front and rear walls of the tank ready for carbon reinforcement, then layed up uni-directional tape along the long axes and 2/2 twill weave over the flats, wrapping around the corners an inch or so. With the left over resin we repaired a slightly frayed edge where the carbon was too deep for the wing recess during the previous layup. I pinned down a couple of flexible stainless rulers over the peel-ply to keep the edge flat, which worked pretty well.