With the frames, stem, and transom completed, I started working on the bottom of the boat, and found several jobs that my shop is just too small for.
I needed three twelve foot cypress one by tens. The lumber yard was out of twelve footers, so they gave me fourteens. I got them into the shop without sacrificing any light bulbs or windows, and laid them out side by side on saw horses.
After I cleared some space and moved the table saw, I had room to fit them over the jointer, but I made several passes and realized there was no way I could handle boards that long by myself. Even with my girlfriend Sally helping, I couldn't keep the boards flat against the fence for the whole fourteen feet.
This is the half breadths of the body plan; the vertical line in the center is the stem of the boat, and each of the lines next to it are the profiles of the frames, or ribs of the boat, which double as the molds that the planks will be bent around. I laid these out on half a sheet of masonite with a colored pencil, plotting points from the table of offsets. These are the lines that I'll use to make the patterns for the frames and transom, and it looks to me like I won't know whether I hosed the job up or not until I'm putting the planks on the boat, which will be much too late.
Once the lines were down, I laid the masonite on the floor and for each station, put nails on their sides at each plotted point, and then laid a piece of pattern stock on top of it and stepped on it, transferring the points to the pattern stock.
About a year ago, my girlfriend gave me a book entitled Wooden Boats by Michael Ruhlman (Penguin Books, 2001). It was written about a boat yard on Martha's Vineyard that builds plank on frame wooden boats using traditional methods and materials. That book completely captured my imagination. It's not a how-to, but is mainly about the romance and beauty of wooden boats and the builders' reasons for choosing to build a type of boat that has long been almost completely replaced by fiberglass, aluminum, and modern manufacturing.
I finished sanding the epoxy and cloth on one side of the boat and have one more side to do. This is tedious work and it seems to take forever to finish. The now smooth layer of epoxy and fiberglass cloth will get one more coating of epoxy but it will be Progressive's Low-V epoxy which flows and levels easily. This will be then covered with varnish or some other clear coat with UV inhibitor.
To make things more interesting, I started fitting one of the rails. The Thistle has some tumblehome in the starn and the hull flares out in the bow. That means quite a bit of shaping to get things to fit. Larry Ligget has a nice set of videos on Youtube showing how this is done. I'll embed part 1 below.
I really like Progressive No-Blush epoxy and no, I'm not paid by them for this endorsement. I've worked with different brands of epoxy over the last 30 years and have developed a sensitivty to several of them. Not so with No-Blush. I also like the way it sands. Epoxy gets harder as it cures. Try to sand it too early and your paper will gum up and the epoxy will heat up and turn to gunk on your sand paper. Wait too long after the cure and it will be hard and difficult to sand. If you time it right, you'll have easy sanding without clogging and No-Blush seems to have a good two-week window where it's easy to sand.
Last week I sheathed the inside of my Thistle with 3.7 oz fiberglass cloth and epoxy. Before this can be varnished, it must be sanded smooth, first with 80 grit and then eventally up to 150 or 220. Areas in the boat that will get epoxy paint (right next to the keelson where the crew's feet go) will be painted and the rest of the boat will be left natural. The cloth will be transparent under epoxy and varnish.
Some general sanding tips:
The first step in strengthening the hull was to lay up some fiberglass tape under the seat supports. These have now been sanded and the edges feathered. Next we'll sheath the inside of the hull with fiberglass cloth and epoxy. The purpose in doing this is twofold. Once finished with new wood and lighter mahogany rails, this Thistle will be underweight. My last wooden Thistle (1014) was 30 pounds light and could not be raced until I added six 5-pound dive belt weights distributed around the hull. Thistles must weigh 515 pounds when racing. Class rules allow for the application of fiberglass cloth inside the hull to add weight. You can't just add it in key areas to stiffen selected parts of the hull. It has to be added over the entire inner surface to be legal. That's fine for us because we need the extra weight and we want the other positives fiberglass and epoxy give us, that being a totally sealed hull with added abrasion resistance. The inside of a Thistle is a busy place when racing.
This is a great video of the making of a laminated Firefly hull. Thistle hulls were made using the same technique. CLICK to play...
Now that the hull is sanded clean and all the old wooden parts removed, it's time to start rebuilding. The glue used to laminate in these 1950s era Thistles can become brittle and fail after all those years. This is even more true in areas of high stress in the hull. You'll often find stress cracks in the laminate (5 layers of 1/16" mahogany) around the seat supports. If the boat has been sitting on a trailer with inadequate support you'll find stress cracks or delamination in that part of the hull. All of these areas need to be repaired and strengthened to meet our goal of a boat with another 50 years of competitive sailing.
I'm going to try to post a few shots of my progress