: . . Water in any of
: its phases can easily pass through a styrene-size wormhole. Surface
: tension comes into play, but the molecule size does not change.

Good point. There is less surface tension in the watervapor, and the molecule size does not change. It is the tendency of the liquid water to form drops or other large accumulations -- because of the surface tension -- that makes it so difficult for liquid water to travel through polyester based fiberglass.

The number of commercially produced fiberglass canoes, kayaks, motor- and sail-boats attests to the fact that you don't get a lot of water leaks thru the "wormholes" in the resin of a fiberglass hull. There may not be a lot of water vapor that makes it's way in, either, but it might slowly accumulate. With a boat that has a wood core, any water vapor that gets in, and stays, can eventually cause some kind of problem.

It seems to me that with the amount of water vapor in the air on any humid day, it wouldn't matter very much whether the boat was in the water or on a rack in the garage. This could be a paradox, but I've no knowledge of boats that are stored "dry" having rot problems.

This discussion keeps coming up when people compare epoxy to polyester resin, so perhaps it is getting more attention than it should. Considering all the OTHER possible ways that a kayak or canoe can be damaged, water vapor penetration is a rather minor problem. Landings on rocky beaches are probably far more damaging.

Thanks again for the reminder on molecule size.

PGJ