Peter Im far from a scientist but Im in the remodeling buisness, and this has been a problem in the past with aluminum and treated lumber. Generally speaking if you are going to use treated around aluminum must put down a barrier over the aluminum so the aluminum will not get eaten by the chemicals in the lumber. If i was going to do a boat over I would get a piece of aluminum for my deck expensive yes but maintence free. My dream boat will have aluminum decks no lumber, and coat the decks with that spray they use in pick up bed liners. Though I would chime in and tell you what I know.
Bob