the weight of the bare hull all depends on the wood you use how thick etc ive never weighed my 36" boat so i dont have a clue.w3bby might know how much his weighs but like i said its all up to you how lite the boat is depending on what wood you use for the build.go lite on the deck and that will keep the weight down a bit 1/16 as i said before would be best.marine ply is pretty water proof as it is the epoxy will just seal it all and make sure theres no gaps at the seams etc. just seal it all inside too to protect it from the petrol and all will be well.all the seams need to be glassed inside too for extra strength,you can use thin strips of matting for this or glass fibre tape!!.engine rails need to be glased in the same way too.also the forward sections can be made water tight and fill them with floatation(pool noodles or similar).this will keep her afloat till you get to her if you do flip [X(] at least the waters warm if you do need to get wet lol.make sure you get good hardware ,stainless steel and or alluminium will not rust.make sure you seal the electrics well too just in case.sorry i couldnt help more on the weight but no two scratch built boats will be the same anyway.doesnt look like ill get that free trip to greece .