You're getting good advice from two directions. If $200 is important in your
life use fir plywood and hope your encapsulation efforts were merely PERFECT.

I, OTOH, being totally anal would not sleep well knowing the job I'd done was
not as perfect as I could make it. Really, it would disturb my sleep!! I
often wish it wouldn't, but what can I do? So, I'd use the best marine grade
ply I could find and treat it IAW WEST System advice. Get their excellent book
if you do not have it.

Yes, it's true..... I wax the gelcoat in my boat's bilge. :=)

Butch

"Mark Davis" wrote in message
ink.net...

snip

My ideas:
1) For the deck I am thinking of using 3/4 inch plywood (A/B not
marine
grade) and then encapsulating it in fiberglass then adding a newer style
gelcoat with non-skid on the top side.

I have no trouble with using good quality fir plywood in an application such
as this as long as you coat both sides, edges, and any screw holes in epoxy.
Spend the money on the epoxy, not the plywood.

I see no need to use any glass. I also see no need to go thicker than 1/2"
unless the stringers are more than 24" o/c. Half inch may be a little
springy, but shouldn't be a problem.

Gel coat is not a good coating -- indeed the only advantage of gel-coat is
that it is easy to spray into a mold -- many expensive glass boats are
painted, at least for boat shows. Instead, use a two part urethane, or just
the epoxy, paying attention to the fact that raw epoxy is not UV resistant.

Remember that in using fir, you will have troubles with the grain showing
through. Best thing is to coat the sheets before installing, while they are
flat, with enough epoxy so the fir is hidden under an epoxy lake. West
System has instructions for doing this.

2) For the cabin floor I would use the same plywood encapsulated in
fiberglass again to prevent rot, then carpet over the floor or possibly do
the same treatment as the deck.

Same comments. Here the question about thickness applies even more. Our
Swan 57 had a 1/2" plywood cabin sole.


--
Jim Woodward
www.mvFintry.com