I have a 17' Arrowglass Tri Hull, which I am in the process of replacing the flooring. I have seen numerous posts about this, but I am still not sure if I should use treated plywood or not. My concern with treated plywood is when it starts to dry out it will start twisting. I have also noticed in the bilge there are two plugs, one on each side. They extend through the stringers. What is the purpose of these? Should these be removed if the boat would have water under the deck? Thanks.