whatever you put over the wood... marine vinyl or whatnot... your going to get a layer of moisture inbetween the vinyl and the wood anyways. It will get in there!!
How bout this....
take 3 samples of the wood your using in the boat and set them aside (scrap wood)
get some good high quality polyester fiberglass.(not the stuff at autozone or home depot)
Rough up your wood with 36 grit on a dual action or orbital sander. Mix up 3 batches of glass in 3 containers according to the directions on the box... in container 1 do not thin it. in container 2 thin it slightly with acetone or whatever the product calls for to thin it... in container 3 thin it a whole bunch.
let it cook off overnight.
on day 2, sand the pieces with 150 grit to rough it up, blow off and wipe down with cloth lightly damped with acetone.
mix up 1 batch of glass not thinned... and go over all 3 test pieces again...
let it cook off another night
day 3.... run all 3 pieces through the saw and see which one you like better.
