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To make the sides and bottom, you need to join two sheets of plywood to make one long sheet. The panels are joined
by "scarfing" them together.
Guide on how to scarf plywood sheets.
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| Panels joined with a scarf joint |
Using the dimensions on the plans, loft the side, bottom, and deck panels onto the joined plywood sheets. Drive
a series of nails into the plywood along the curves you lofted, and use wooden spline, along with some weights to hold the
spline in position as you draw the curves. I tried both a jig saw and circular saw to cut these curves. I prefer the
jig saw. I found it more difficult to cut to the curve accurately with the circular saw. The jig saw was easier to stay on
the line, but it produced a rougher edge. I touched up the edge with a block plane.
Guide on how to loft curves.
After you cut out the panels for one side, they can be flipped over and used as templates to make the other side.
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| Cutting out the bottom, side and deck panels |
Lay the two bottom panels on top of one another and drill a series of holes along the lower edge spaced about 3" apart.
Stitch the panels together using wire ties or bailing wire. Spread the panels apart and use a scrap piece of 2x4 to
hold the panels open.
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| Joining the bottom panels |
Stitch the side panels and the bulkheads in place. Fit the centerboard trunk in place temporarily to make sure
the bulkhead spacing is perfect. The centerboard trunk is initially cut a little oversized on the top and bottom and
should now be measured and cut to the exact size. Use a pencil and a scrap wooden spacer to trace the curvature of the
hull onto the bottom of the centerboard trunk sides. Cut the trunk to the curve and check the fit. The trunk should
match the hull curvature and line up with the top of the middle bulkhead. Place the deck frame bulkhead in place (visible
in the next photo after this one), draw a line on the centerboard trunk between the tops of the deck frame bulkhead and the
fwd bulkhead and cut the centerboard trunk to this line.
How to stitch the hull.
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| Stitch the bulkheads in place |
Build the centerboard trunk. Make sure you fiberglass the inside of the centerboard trunk before you assemble it
because it's near impossible to reach in there afterwards. Cut two holes in the hull just big enough for the log blocks
of the centerboard trunk to fit through and set the centerboard trunk into place. Don't cut the centerboard slot in
the hull yet because the hull will hold its shape better if you cut it later. Mix up some epoxy and wood flour to the
consistency of peanut butter and apply a small fillet in between all of the stitches. Avoid getting epoxy on the stitches
themselves. This is called "tabbing". Allow to cure 24 hours. The stitches can then be removed.
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| Tack the bulkheads in place |
Apply fillets and fiberglass to each bay. I prefer to work one bay at a time and complete the bay in one session,
but you need to be prepared and work fast. It helps to have an assistant. Start by applying clear epoxy to all joints.
Next apply a large peanut butter fillet over the joint. Apply a 4" wide strip of fiberglass over each the fillets and wet
it out with clear epoxy. Lay sheets of fiberglass cloth over the flat areas, cut oversize so that they overlap
at the joints, and wet them out with clear epoxy using a plastic squeege. Be careful not to press too hard on your fillets
or you might deform them. Do the smaller bays at the bow and stern first where any mistakes will not be visible as you
learn the techniques. Cut all the fiberglass cloth pieces to size before you begin. Do all the work outdoors if at all
possible to avoid breathing the epoxy fumes.
I found the section on making "Lay-ups" to be especially useful.
If you look closely, you may notice that I sealed the top of my centerboard trunk with a piece of 1/2" plywood instead
of building the removable seat and open centerboard trunk that the plans call for. I did this for two reasons:
1) I didn't want any water leaking into the boat from the top of the centerboard trunk. 2) When beaching the
boat or when the boat sits on my trailer, it is resting on the centerboard. I didn't want the centerboard pushing the
seat off. Instead, my centerboard rests solidly on the plug. The drawback to doing this is that if you get
rocks or gravel inside the centerboard trunk, thus jamming the centerboard, it is more difficult to clear them out.
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| Apply seams and fiberglass interior |
After the epoxy cures from the previous step, apply two more coats of epoxy. Always sand the previous coat thoroughly
before applying the next coat. In this photo, you can see where I removed some material from the center bulkhead, right
where the centerboard trunk attaches to it (compare with the first photo which shows the bulkhead before the material was
removed). This frees up some space in the cockpit.
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| Apply two more coats of epoxy over fiberglass |
Flip the boat over. Cut out the slot for the centerboard. Round all edges and sand. Attach skeg and bow stip (on my boat
I ommitted the bow strip). Build a large fillet on skeg-to-hull joint and a regular sized fillet on the bow strip-to-hull
joint. Apply 2", 4", and 6" wide strips of fiberglass to edges using the lay-up technique, then fiberglass the bottom of hull.
How to shape and fiberglass the hull.
Note: It really helps to build the boat on a movable cart so that you can easily move the boat outdoors, turn it
around, and work on the boat at a comfortable bench-top height. I've seen some really elaborate carts built by
other boatbuilders that were works of art in themselves. My cart consisted of a discarded plywood shipping crate measuring
about 4' long by 2' wide by 3' high. I mounted 4 wheels (casters) under it, and screwed some 2x4's to the top.
It also doubled as a scrap wood bin.
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| Cut centerboard slot, attach stem, fiberglass bottom |
Flip the boat back over. The gunnels are attached with thickened epoxy, stainless steel screws, and plenty of clamps.
I added a stringer around the cockpit opening to support the deck and cockpit combing. This also allowed me to use a router
with a flush trimming bit to cut the cockpit opening in the deck. I also installed scrap plywood strips on the bow and
stern where the deck panels join together. Don't forget to install the mast step.
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| Install gunnels and cockpit stringers |
Two coats of epoxy are applied to the underside of the deck and then the deck is glued and screwed in place. The
deck is cut oversized, installed, and then trimmed to size. I used my router with a laminate bit to trim the deck flush
with the gunnels and cockpit stringer. It is not necessary to fiberglass the deck. Fiberglass is used to
add strength and abrasion resistance. The deck requires neither, so two coats of epoxy will do.
The cockpit coamings are installed. I cut the fore and aft ones to size first, rounded the edges with my router and epoxyed
them in place. Then I did the side ones the same way. I didn't need to use any screws because the stringer I installed
previously provided plenty of glue area. Most of the clamps have been removed prior to this photo. It took a LOT of
clamps bend and hold the side combings in place. I choose to make my coamings so they stick up only 3/4" above the deck
(plans show 1 3/4") to make them more comfortable to sit on while still keeping the water out.
Here I'm working on the centerboard. The centerboard is made from a piece of 3/4" plywood. A bushing is needed
for the centerboard pivot. I used a stack of stainless steel washers 3/4" high epoxyed in place. About 16 pounds
of lead weight is required to keep the centerboard from floating. I bought a bag of lead shot, used for reloading shotgun
shells, from a local gun shop. I used my router to cut a series of pockets in the centerboard for the lead shot. I set my
router depth to about 1/16" less than the thickness of the centerboard to avoid cutting all the way through. After filling
each pocket with lead shot, I poured clear epoxy over the shot to hold it in place. The centerboard was then fiberglassed.
Here I'm machining the mast. I made the mast from a douglas fir 4x4 purchased from Home Depot for $12 (although
I had to visit several Home Depots before I found one with no knots or splits). I didn't trust my ability to plane
the mast so I made a makeshift lathe that worked great. I screwed a bolt into each end of the 4x4 and made two little
T-shaped plywood stands with a notch for the bolts. Setting this contraption on my workbench places the mast horizontally
and allows me to rotate it. Next, I laid two rails on either side of the mast. These rails can be tilted to the
correct angle to machine the tapers in the mast by attaching the proper sized spacer under each end of the rails. Finally,
I attached my router to a piece of plexi-glass. The router contraption sits on top of the rails, allowing me to slide it along
the length of the mast. By sliding the router lengthwise along the rails while gently rocking the mast back and forth,
I was able to machine a perfect mast.
After fiberglassing the surface will be uneven. I used 80 grit sandpaper attached to piece of plywood to knock
down the lumps and bumps. Next, I mixed fairing compound with epoxy and covered the entire boat. I don't know
exactly what fairing compound is made of, but it appears to be a finely ground plastic powder of some sort. Mix it with
epoxy to the consistency of honey and spread it over rough areas with a plastic spreader. Fairing compound sands rather
easily and goes a long way toward giving your boat a smooth finish. Keep applying the fairing compound, allowing it
to cure, and sanding until all the voids and edges are gone.
When you're done fairing, apply primer. It's a good idea to make sure your primer and paint is made for application
over epoxy. Some types of paint do not adhere to epoxy because epoxy can develop a "blush" which is a greasy, waxy coating
that can continue to manifest itself for up to one month after the epoxy was applied. In any case, wipe the boat down
with clean water and a clean rag to remove any blush, prior to application of the primer. I used Interlux brightside
paint with Interlux epoxy barrier-kote primer, which is made specifically for application over epoxy.
Interlux paint is a little expensive, but I think it's worth it. With the painting done, now we're ready for some
varnish.
The rudder, tiller, mast, boom, and sprit pole all get 2 or 3 coats of epoxy, followed by 2 or 3 coats of varnish.
I fiberglassed the bottom half of my mast for some added strength.
Masts, rudders, spars and daggerboards.
Several of us have concluded that the boat can benefit from making the rudder about 20% larger. It helps the boat
tack better in light air. Also, it is better to build the rudder from 3/4" ply instead of 1/2" ply, especially when
increasing the area, for added stiffness.
Rigging: I rigged my boat just like the Crawford Melonseed.
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