I guess the true response would be
How will the finial wood be finished..and what material will be used to seal any seam?... There are many good wood species that work in the marine environment, depending on the final application and finish..... there are however, few woods that can be left without some kind of finish,,,,even Iron wood used undewrwater will permeate water eventually. submerged PT wood pilings even rot, I know , we've bumped into a few!But as Robert mentioned wooded boats have been built for centuries using a variety of woods.... The Rockport Marine is a great web site for wood boat building.here is a sample of construction materials from one of their projects, Louise:"LouiseLouise, a Buzzards Bay 25, was launched on May 23, 2002. Designed by Nathanael G. Herreshoff, the first four boats were built in 1914 by the Herreshoff Manufacturing Company. This design may have been Herreshoff’s favorite. Construction is Atlantic cedar planking over white oak frames, teak garboards and mohagany sheer strakes with silicone bronze fastenings. Floor timbers, plank keel, and stem are Angelique. The decks are high grade marine plywood sealed with epoxy and dynel cloth. The cabinsides, coamings, and transom are Honduras mahogany and the toerails, cabin and cockpit soles are teak. Her gaff rig consists of sitka spruce spars, rigging by Gambell and Hunter Sailmakers of Camden, Maine, and sails by Roy Downes. Dimensions are LOA 32’; LWL 25’; beam 8’9”; draft (board raised) 3’. Following her sea trials, she was delivered to the Bahamas where she now resides."Even marine plywood has its place, used inside the cabin, below waterline saturated in epoxy...When I was apprenticing in college we built a FOUNDATION of a house with pressure treated sills, studs and sheathing,,,,gooped a mixture of creasote on the exterior, under grade then sheathed that assembly in a clear plastic vapor barrier,,,and backfilled,,,,,,,,,builder said it would last 20 years!!!....wow, most people arnt even finished paying off the mortage by then!...I wonder how that house is doing????My preference for boat woods??? I love working in Mahogany and white oak and then teak.