it honestly is that thick, the wood in the stringers is redudnant, they are wrapped with about 1/4" of fiberglass, that combinded with what is basically a 3/8' minimum hull thickness makes it so the wood never really takes any load. even the transom double laminated with three sheets of marine ply, and from what I can tell they epoxied the cut ends of the plywood since the wood on mine is still rock hard. That being said I would bore holes through the stringers and epoxy a fiberglass tube through the ends of the stringers to let water drain out if it gets trapped on the outboard side of the stingers, since everything on the outboard side is foam filled. I will be posting that process soon. Ive already drilled the holes and there was a bit of moisture on one side, so I've had my vacuum pump running on it with a filter to draw out any remaining moisture.
The overall structure of these boats is why I consider them to be one of the better boats for the west coast, im pretty confident you could run aground on rocks and it would still be none the worse for wear.