How to Build a Dory Boat Structure, Part 1

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A stable sailboat doesn't have to cost an arm and a leg. Bill Hyslop details how to build the structure of this boat and how to do it cheaply.
A stable sailboat doesn't have to cost an arm and a leg. Bill Hyslop details how to build the structure of this boat and how to do it cheaply.
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Figure 2. Each side is fabricated from a 4-by-10-foot section of 1/2-inch plywood sawn in half lengthwise and butt-jointed together end to end.
Figure 2. Each side is fabricated from a 4-by-10-foot section of 1/2-inch plywood sawn in half lengthwise and butt-jointed together end to end.
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Figure 3. To loft the curved bottom line, lay out one side on a flat surface. Drive in nails at points A, B and C. Then bend a long, straight-grained, thin piece of wood around these nails and draw the bottom line as shown. Once the line is marked, cut out one side and use it as a pattern for the other.
Figure 3. To loft the curved bottom line, lay out one side on a flat surface. Drive in nails at points A, B and C. Then bend a long, straight-grained, thin piece of wood around these nails and draw the bottom line as shown. Once the line is marked, cut out one side and use it as a pattern for the other.
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Figure 4. It must accept all the strain of slapping over waves and plowing into surf. In fact, the joining plate shown in the diagram probably represents the inside limit on size. You could easily extend yours to reach all the way between the two nearest ribs. The bigger the plate, the firmer the joint. Next, fasten a beveled 1-by-2 chine along the inside bottom of each side. (Remember, you'll have a
Figure 4. It must accept all the strain of slapping over waves and plowing into surf. In fact, the joining plate shown in the diagram probably represents the inside limit on size. You could easily extend yours to reach all the way between the two nearest ribs. The bigger the plate, the firmer the joint. Next, fasten a beveled 1-by-2 chine along the inside bottom of each side. (Remember, you'll have a "right" and a "left"!) Each chine is beveled so the sides will slope up and outward from the floor at a "flair angle." Then, 1-by-1 ribs can be joined to the chines as shown. The transom is also pictured here, but should not yet be fixed in place.
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Figure 5. Now attach the bowstem to one side as pictured. The stem is a 40-inch-long 2-by-3 that is beveled on both sides at 25 degrees. This diagram shows a cutaway view, looking down on the plywood frame at the bow.
Figure 5. Now attach the bowstem to one side as pictured. The stem is a 40-inch-long 2-by-3 that is beveled on both sides at 25 degrees. This diagram shows a cutaway view, looking down on the plywood frame at the bow.
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Figure 6. In order to shape the hull, you'll need a center frame around which you can bend the sides. This frame should be 48 inches wide at the top, including the thicknesses of the two sideboards. At the lower end of the guide, fix a substantially longer piece of wood. This will be used to maintain the angle of flair during construction. C-clamps are used all around: on the top for firm clamping action and on the bottom to permit easy adjustment of flair as the hull is trued.
Figure 6. In order to shape the hull, you'll need a center frame around which you can bend the sides. This frame should be 48 inches wide at the top, including the thicknesses of the two sideboards. At the lower end of the guide, fix a substantially longer piece of wood. This will be used to maintain the angle of flair during construction. C-clamps are used all around: on the top for firm clamping action and on the bottom to permit easy adjustment of flair as the hull is trued.
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Figure 7. Bending the sides together is a little like stringing two 20-foot longbows at once. It helps to soak the plywood and keep it wet while it's being curved.
Figure 7. Bending the sides together is a little like stringing two 20-foot longbows at once. It helps to soak the plywood and keep it wet while it's being curved.
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Figure 10. The transom is simply made of boards fitted over a four-piece frame. Its top is rounded and designed to stand up above the sides, like a backboard.
Figure 10. The transom is simply made of boards fitted over a four-piece frame. Its top is rounded and designed to stand up above the sides, like a backboard.
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Figure 8. Our shaping tool was a
Figure 8. Our shaping tool was a "twist-pull" made with some strong twine and eye screws.
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Figure 9. The transom fits into the ship's stem. It's beveled horizontally on both edges at a 22 degree angle to mate smoothly with the ends of the sideboards. It also tapers vertically to match the angles of flair of the boat's sides.
Figure 9. The transom fits into the ship's stem. It's beveled horizontally on both edges at a 22 degree angle to mate smoothly with the ends of the sideboards. It also tapers vertically to match the angles of flair of the boat's sides.
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Figure 11. For final fitting at the bow, use triangular shims lightly nailed to the frame to keep the C-clamp from sliding off.
Figure 11. For final fitting at the bow, use triangular shims lightly nailed to the frame to keep the C-clamp from sliding off.
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Figure 12. Once stretched and fastened, the sides will tend to crimp at the point where they bend around the center frame. To prevent this, drive 2-by-2 cross members toward the bow and stern. Hina has four such supports, the two centermost of which lie about two feet from midship.
Figure 12. Once stretched and fastened, the sides will tend to crimp at the point where they bend around the center frame. To prevent this, drive 2-by-2 cross members toward the bow and stern. Hina has four such supports, the two centermost of which lie about two feet from midship.
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Figure 13. To test for symmetry, stretch twine along the boat's axis and measure distances from either side to the line with a yardstick.
Figure 13. To test for symmetry, stretch twine along the boat's axis and measure distances from either side to the line with a yardstick.
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Figure 14. EDITOR'S NOTE: In our carpenter's alternate method, you would nail not only from the hull into the crossbeam, but also from the lip of the 2x4 into the chine, and from the rib, which isn't pictured, into the beam. 
Figure 14. EDITOR'S NOTE: In our carpenter's alternate method, you would nail not only from the hull into the crossbeam, but also from the lip of the 2x4 into the chine, and from the rib, which isn't pictured, into the beam. 
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Figure 17. Excess wood can be removed with a rasp. Check your work frequently with a straightedge. This joint is the backbone of your boat, so take the time to do it right.
Figure 17. Excess wood can be removed with a rasp. Check your work frequently with a straightedge. This joint is the backbone of your boat, so take the time to do it right.
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Figure 16. You can tell if you need to plane by laying a straight edge across the chines and sides. It should fit snugly against all surfaces.
Figure 16. You can tell if you need to plane by laying a straight edge across the chines and sides. It should fit snugly against all surfaces.
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Figure 15. In this kind of vessel design, the bottom plays an important structural role. Its installation is not difficult, but should be done carefully to assure maximum strength and watertight joints. The chine bevel should ensure a perfectly smooth fit between the sides and the floor. Regularity of surface along this junction is crucial. One way to make sure the bevels on both sides are equal is to rip the chines from a wider board.
Figure 15. In this kind of vessel design, the bottom plays an important structural role. Its installation is not difficult, but should be done carefully to assure maximum strength and watertight joints. The chine bevel should ensure a perfectly smooth fit between the sides and the floor. Regularity of surface along this junction is crucial. One way to make sure the bevels on both sides are equal is to rip the chines from a wider board.
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Figure 21. You can further finish and waterproof this seam by gluing and nailing a small trim piece along the outside.
Figure 21. You can further finish and waterproof this seam by gluing and nailing a small trim piece along the outside.
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Figure 19. Lie the 4x8 plywood sheets over the hull and draw an outline where they hit the bottom.
Figure 19. Lie the 4x8 plywood sheets over the hull and draw an outline where they hit the bottom.
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Figure 18. The bottoms of the bowstem, transom and crossmembers should also fit flush against the straightedge.
Figure 18. The bottoms of the bowstem, transom and crossmembers should also fit flush against the straightedge.
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Figure 20. When cutting the bottom, give yourself a little extra. Excess can be easily removed with a rasp or belt sander after the underside has been fastened in position. Butt-join the bottom pieces as you did the sides. Then, attach the ship's belly using plenty of glue and fasteners, preferably screws of brass, galvanized steel or other metal coated with a saltwater resistant substance. Fasten it to the transom and struts as well as the chines.
Figure 20. When cutting the bottom, give yourself a little extra. Excess can be easily removed with a rasp or belt sander after the underside has been fastened in position. Butt-join the bottom pieces as you did the sides. Then, attach the ship's belly using plenty of glue and fasteners, preferably screws of brass, galvanized steel or other metal coated with a saltwater resistant substance. Fasten it to the transom and struts as well as the chines.
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Hina is a floating backpack that will carry two people as far away as they wish to go. As with any backpack, the lighter the better. So, we built her from sturdy, but not heavy, woods. Our basic hull materials included those listed above.Plywood should be waterproof, which means laminated together with glue that won't disintegrate at sea. And the 5/4-fir specified here is a rough lumber measure which assures you of a true one-inch thickness on the finished board. If you ordered simply 1-by-2 fir, you'd end up with a planed piece of lumber measuring only 11/16 x 1 5/8. You want the full inch.Just about everything else that went in Hina consisted of short, scroungeable lengths. Such scavenging not only saves money, but draws you into the design process as you adapt your plans to utilize what's available.
Hina is a floating backpack that will carry two people as far away as they wish to go. As with any backpack, the lighter the better. So, we built her from sturdy, but not heavy, woods. Our basic hull materials included those listed above.Plywood should be waterproof, which means laminated together with glue that won't disintegrate at sea. And the 5/4-fir specified here is a rough lumber measure which assures you of a true one-inch thickness on the finished board. If you ordered simply 1-by-2 fir, you'd end up with a planed piece of lumber measuring only 11/16 x 1 5/8. You want the full inch.Just about everything else that went in Hina consisted of short, scroungeable lengths. Such scavenging not only saves money, but draws you into the design process as you adapt your plans to utilize what's available.

The oh-so-proper yachting press would have you believe that you must spend at least $2,000 to own a twenty-foot cruising sailboat. Hogwash! My lady and I built and outfitted Hina for less than $300, and $90 of that was spent on a suit of used sails alone!

Instead of using costly marine hardware, we made our own fittings from scrounged materials. We combined efficient, modern design concepts with older “tried and true” methods. At the start, we had only limited woodworking skills and a few hand tools, no plans and no blueprints to follow. We relied simply on intuition plus what little we could learn about the boat designs of faraway times and places.

The result: a crisply performing vessel that far surpassed our highest hopes. Hina sails beautifully! On a 2 1/2 month, 400-mile cruise around upper Lake Michigan, under all kinds of conditions, she kept us safe, dry and reasonably comfortable. In heavy weather, she took five- and six-foot waves easily and her classic lines drew admirers at every port.

Because she was such a success, and because I’d like to aid others who’ve dreamed of living on the water, I’ve drawn up this description of the Hina and how we built her.  

The Dory Story

  • Published on Jan 1, 1976
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