I have an 11' long canadian canoe with a lug sail. I am very pleased with the hull shape but it has been kept out in the open for some years and the ply is starting to go. I'd like to cover it in grp and remove the ply, so I end up with a grp hull. I will glass some stringers inside when the ply is out, but can anyone advise me how many layers of what weight cloth I should use for adequate strength/rigidity. (I know I ought to make a female mould and then lay up the hull inside that, but the shapes are not right - plumb bow and stern, and I'll never get the plug out in one piece.)