I want to fair
: the haul and deck together after I thick epoxy them together. That means
: fiberglassing the insides of the haul and deck first. I am thinking of using : One layer 3.75 oz. open weave glass inside and one 3.75 layer on the outside, : with reinforcing strips on the inside and outside of the deck/haul joint and
: also on the stem/stern/keel.
John,
With a 12' boat you're not greatly increasing the weight by going to 2-3.75 oz. plys on the exterior or one 6 oz. I think if you go this route you can eliminate much of the tape reinforcement on the exterior. Put it inside where fairing isn't as critical. If you tape the places subject to the most strain on the inside you can get away with a lighter cloth there. Most of the destrucive testing of glass stripped wood panels shows that failure occurs on the side of the panel put in tension. This would be the interior of the boat when it hits or grounds on something. The exterior when you drop your butt in.

So it would make more sense to use heavier cloth on the interior except the exterior is subject to abrasions, contusions and other insults.

As for fairing the unreinforced hull I have no experience. I guess it all depends on how aggressive your technique is. Good luck.