Western Red Cedar is used quite a bit for cold molding and is readily available. Similar woods would be White Cedar and Juniper. Black Locust is great for frames and exterior trim also commonly used for wooden cleats
. Spruce has little rot
resistance but due to it's light weight is/was used for masts. Much of the mahagony on the market today is not true mahagony so the real stuff gets a bad rap. The real stuff is a great boatbuilding wood used for planking, cabin
sides, and exterior trim. It comes from Central America
. African "mahogany" may be okay but Philippine is crap. The domestic plywood(fir) is so poor here that you would need to find a source for marine
grade fir or imported plywood
like okume, merenti, mahagony,etc. Long leaf yellow pine salvaged from old buildings is excellant. I built a deck
for my house 20 years ago with this and a scrub and clear sealer applied every few years make it look as good as the day I built it. Oak is used for frames, deadwood, keels and other structural members due to it's great strenght but I would not use it for exterior trim. There is white and red oak and I think white is prefered.
Wooden boats rot
from fresh water
leaking in from rain or whatever. Saltwater acts more like a preservative.