on my old 11 ft aluminum, i used a pair of pliers to slowly bend up and shape the curled lip into a larger, flat platform on which to mount the rod-holders. it was still not quite large enough of an area, so where the mounts hung off the edge towards the inside of the boat making drilling impossible, i used overly-large flat washers to pinch the platform and make the mounts sturdy. sound jury-rigged, but it worked, and still is intact. i'll try and post pictures soon