My father in law used composite decking and stainless hardware on his dock. The piers and substructure was treated plywood. 10 years later and it still looks great. He also affixed tar paper to the upward facing surfaces in the pier and substructure to allow water to run off.
Previous: 1993 Prostar 205
Red 1998 Ski Nautique, PCM GT40, 310 hp, , Acme 4 blade, Perfect Pass SG/Zbox.
Be kind. Have fun.