First off you are not missing a page out of the manual, and you are not clueless, .......I can answer about the paranoid ;)

The way the kit is designed you only glass the cockpit on the inside of the hull.  By the time you tape all the seems the is quite a bit of glass in both ends.

There are builders on this site that chose to glass both inside and out but you would need to purchase more glass cloth.  I chose not to, as the fiberglassing was the one skill I was learning as built my WD12 last year.  I did not trust myself to make it neat.

Good luck and enjoy the build,

DD,

What Shawsheen said. There's a WD12 at the CLC showroom that has been doing demos for something like 7 years. It's probably had the toughest life of any WD12 on the planet. It's still in really good shape, even though only the cockpit is glassed on the interior. A properly epoxied piece of wood is totally waterproof. Fully cured epoxy is as hard as formica.

The WD12 design gets most of its structural strength from the plywood. The various curves pre-stress the wood and form a stress-bearing monocoque hull. The outer glass is mostly there for additional abrasion resistance since the boat may contact rocks, shells, asphalt, concrete, broken glass, etc. Since you're probably not going to be putting any of that inside your boat, only the part of the cockpit where you're likely to step is glassed. The rest of it depends on the formica hardness of plain epoxy.

On the hybrid, the deck is glassed on both sides to also provide additional tensile strength. This is necessary because of the many strips making up the deck. Everywhere you have a joint, the long wood fibers stop dead. Tensile strength is best provided by long continuous fibers that spread the load. A big piece of glass does that very nicely.

The underdeck glass also provides additional abrasion resistance for the relatively soft cedar. Finally, it also helps make sure that the myriad joints are watertight. But all this is more than what is needed for solid continuous pieces of multilayer plywood that won't be exposed to continuous rubbing.

All that said, I'm one of those builders who glassed my WD12 inside and out. I wanted the extra abrasion protection because I planned on using it hard, putting anchors and other metallic gear into the boat. I also wanted the strength of the true wood-cored glass composite construction (even though it was only 4 oz woven cloth) that comes with complete interior glass. I planned on taking it places where there were boulders and interior glass resists punctures better than exterior glass does.

It worked out well for me. Once I had the boat in 3-ft high waves with whitecaps. Every time I rode down the face of one wave I buried in the back of the next one all the way up to the coaming. Whenever that happened, the boat experienced a shuddering flexing. Years later, the boat is still in one piece.

The interior glass comes at a price, though. I had to buy some 8 additional yards of glass and an additional quart of epoxy. Your number will be different because you're building a hybrid and I wasn't. My boat also came in 5 or 6 pounds heavier than if I hadn't glassed it. But it still ended up a full pound less than the design weight, though.

So that's the benefits and costs. Hope this helps make your choice,

Laszlo

Laszlo and Shawsheen,

  Thanks so much for the explanations!  And Laszlo, the photos and commentary on tour web site were great.

DD