Fiberglass, epoxy and mylar sheeting

Oh yes, these are the petrochemicals we love and love to hate.

For the most part, though we call our boat a wood boat, it does contain a lot of components that are decidedly not wood. In fact I recently stumbled upon (in the non-2.0 sense of the word) a classification schema for wooden and "wooden" boats. With a "Genuine Wooden Boat" sitting at 1.1, our boat, or a "Piecewise Laminated Wooden Boat" was listed seven steps down at division 1.2.2.

Anyhow, all this is leading up discussing our recent conversations about adding a fiberglass sheathing to the bottom of the boat. Back when we were choosing plywood for the hull, we passed over locally cut/made douglas fir which requires a complete fiberglass encasing to prevent "checking." We specifically chose fancier, more expensive plywood, okoume (probably logged in Gabon, made into plywood in "France" and China) so that we wouldn't have to glass it. We didn't want the added work or cost, and we wanted something closer to a wood boat at the end of the day. Not a plastic boat with some wood inside it.

But while Okoume doesn't check, its soft. And since we want to be able to drag this boat around, land on barnacles, in surf, etc, we need the bottom of the boat to be fairly resilient. And that means in addition to some skids that we'll add, we need to cover the bottom in fiberglass.

To that end, today I traveled down to Tap Plastics, located on the northern edge of the Mission district here in San Francisco. It was recommended to me by George at Coast Marine, the excellent chandlery up near Fisherman's Wharf. Tap has a really cool old storefront, and a lot, no really, a lot, of plastic stuff. If you are in the area you should stop in sometime.

There are two main types of fiberglass, and we went with S-glass, the 4 oz version. S-glass is fancier and has a higher strength to weight ratio than the more common E-glass, but mainly we chose it for it reported ease of application and out of the potentially misguided hope that it may be more abrasion resistant. Just fyi, the S-glass was $8.50/yd at Tap, and we priced the E-glass at $17/yd at West Marine.

We will be using the same Systems Three epoxy that we've been using for the planking and framing. It should be more than adequate for the glassing we're planning.

We are also planning to try a technique that I saw described on the duckworks website. So I also picked up 16 ft of Mylar sheeting at Tap. They didn't have any available by the foot that was as thick as the .03" mentioned in the duckworks explanation, but I bought some at .005". We'll see how that treats us. Looking at some of the pictures from their step by step, I have my doubts about the accuracy of their reporting. Anyhow, the guy at Tap seemed to think .005 was fine for surfboards so we'll see.