Beginning the D4

I'm working on the D4 again, after 9 years.  I was at a waiting point in the canoe, so I stitched it together with my son, Alston.  He has watched me carry the parts for this boat around the entire time, so he was excited to help.

Recapping what was done 9 years ago,  I cut out all of the panels and the frames.  The panels are a luan plywood, and the frames are AC.  The transoms are 3/4" laminated from 1/4" plywood.  I wanted the option of putting a small motor on it.  I misunderstood the directions and laminated the bow transom as well.  I added an extra pound or 2.  Oh, well.

I am stitching it together with tie-wraps and 3/4" dowels.  I started by screwing the panels to the frames, mid-seat bow fore frame first, stern transom second, bow transom third, then the rest.  We loosely stitched the pieces together.  We will tighten, adjust, and tack the seams later.  Alston came in especially handy, since he crawled under that tiny boat, and fed the tie-wraps back to me.

Side view, through my work cart (next topic).

Front view.

Rear view.  Notice the daggerboard trunk halves, coated on the inside with graphite and epoxy.  These have been done with left over epoxy.

Making the Yoke

The yoke as designed for this canoe was a simple 2" dowell.  I wanted more flair, so I came up with a wavy yoke.  I suppose it is not technically a yoke, since I won't carry this canoe on my shoulders, and it is not designed for that purpose.  It ended a little oval, 1 1/2" x 1 3/4".

The yoke began life as 2 pieces of 1x4 poplar, glued up into a 2x4.  I couldn't see carving a harder wood, such as oak, at least not the first time.

I laid the curve out on the board every half inch.  The curve is just 1 1/2 cycles of a sine wave, calculated on Excel, with a 1/2" foot for mounting.

The shape was cut out, square, with a jig saw (I wish I had a band saw).  If you look carefully, you can see that the octagon has been marked, and the part to be removed shaded with a pencil.

I removed the shaded part with a shaper, a cheese-grater for wood, leaving a rough octogon.  Most of the material to be removed has been removed.  Only a little material has to be removed from the remaining corners to end up with a round form.  Being poplar, it was very easy to remove material.

I did the final rounding of the corners with a 1 1/2 wide, 100 grit sanding belt from the bargain bin at the Klingspor woodworking store.  Drawing the belt back and forth, like polishing a shoe, quickly rounds the wood.

It may not look like it, but this yoke is 35 1/2" long.

I used clamps when I glued it in.  If I did it again, I would use screws through the rubrail.

The Seats

The seats for the canoe as designed are open bottom - a piece of plywood over 1" cleats and supports.  I didn't want to leave it open for various reasons - it would be a hiding place for spiders in storage, it would be a pain to clean, and I wanted to experiment with floatation foam chief among them.  So I added a plywood bottom with foam in the middle, providing about 17 pounds of floatation for gear or provisions.  This complicates assembly, because the frame has to be installed after completion instead of being built in place.

After measuring the seat dimensions, I started with the frame on a piece of plywood.  The visible parts of the frame are from scraps of red oak that I have had for 12 years, bullnose trim  left over from stairs I built in a house I used to own.  The newels on those stairs were not loosely nailed to the floor, like in most houses.  They were screwed to the joists.  No one could crash through those rails.  The scraps were not long enough, so I joined pieces to make them long enough, using lap joints.  The hidden cleats were spruce.

This is a learning project, and this is my opportunity to learn about floatation foam.  I have had this flotation foam since 1999, but apparently floatation foam has a shelf life similar to epoxy.  It is still good.  Floatation foam is a Coast Guard approved, two-part polyurethane mixture that foams when mixed, like expensive Great Stuff™.  When mixing this stuff, the mixture is 1:1, so it is convenient to use identical disposable plastic cups (labeled A and B so you can re-use them for each batch) and pour each part to a line molded in the cups.  I mixed thouroughly, just until it started heating, and poured into the seat frame.  Below, you see the result of two pours on the bottom, and the other seat after trimming.  I trimmed using guitar wires, but it took four because they break so easily.

After filling with foam, I glued the plywood tops on.  The assembly is very stiff and light.

Mounting the seats was not as straight forward as I thought initially.  The plans had a measurent to the top of the seat on the centermost edge.  This measurement is different from the other side.  I used a level to make the seat as close to level as possible, smeared the ends thickly with epoxy putty, and screwed the seats into place using two sheetrock screws on each side maintaining 1/8" separation between the seat and hull.  I put 9 ounce woven fibberglass tape on the upper side, wet on wet.

Below, an installed seat.