I just bought a boarding ladder and intend to keep is stowed on deck until it is needed. It is designed to mount on two keyhole plates, each secured by two bolts. My problem is that I cannot access the inside upper part of the hull on my 1978 CHB. I’ve considered screws since the shear would be nearly vertical but am afraid that wouldn’t be strong enough. I’ve also thought of gluing and screwing a wooden plate to the side so that I can screw the mounts to that, or possible bolt the mounts to the plate and then screw and glue the plate to the boat. Any suggestions or other ideas?