I have decided while I am at it I will replace the transom(coosa) along with the stringers and floor. I do not want to remove the cap and I can get a the transom from the inside, It does not go up into the cap and I think I can router most of it out from the inside and finish off with the grinder. My question is how will I be able to make sure the hull shape stays the same. Should I screw some ply to the outside, or some other method?? The stringers and floor are out.