Seat Supports

To build the seat supports, I first needs to check my CAD dimensions and copy them to the splines. Below shows how I did that with a straight edge, a clamp to hold it against the frame, and combination square. My square has a level which allowed me to confirm I had a slight pitch from the ends; I designed the ends a half inch higher so water would drain towards the center.  

 Here I show the dry fit of the spline, with the cleats clamped on,  and 1 x 3/4" crosspieces. The holes were to save a bit of weight and improve access from the round top hatch you see just to the right--beside they give it that cool airplane look :-). I spaced the crosspieces 8 inches apart and used a level and strait edge to confirm everything was right before marking and epoxy gluing every in. The stern seat was done the same way. Each spline has a limber hole on its low end that you can't see in the picture.

 I used solid clear yellow pine for the aft of the mid seat support. The arching curve are mostly cosmetic and should be as strong as the traditional 1x2" straight hardwood pieces set on edge cleats.

I'll be fitting the seats next time.

Quick update.
Created short epoxy fillets between the wire ties and starting to fit the frames. The first picture is a dry fit of the middle frame to double check everything, the 2nd is of the final front frame cut. After this, I'll pull the wire, finish the fillets and epoxy the 2" tape.

planking

I aligned the bottom and used two screws to attach it to the cradle; this will make working and truing everything much simpler as I go. I'm using 20 gauge copper grounding wire for the stitching. It's a good compromise between flexibility and strength. Most of the copper ties were pushed through from the inside because it will be easier to apply the epoxy fillets to the inside. I used a stitch about every foot or so, just making it tight enough to bring the planks together. There's quite a bit of tension at the transom so I've used two stitches per plank.  

   I've epoxied the planks to the stem rabbet. The narrow piece of wood to the right of the stem is to help align perpendicular to the bottom; it would be very easy to mess this part up. The stern will also be done this way.

So far so good. It's nice to see the boat finally taking shape. Next will be epoxy "welding" the planks and framing.  

Cutting wood

This is going too slow. Last week I started to mark the plywood and yesterday, after double, triple and quadruple checking (hehe), started to cut out the bottom and lower planks. Quite a few people recommended a circular saw with a plywood blade set shallow just deep enough to make a clean cut. I tried it but didn't like the results, more dangerous, even the subtle curve bogged the saw enough to make me nervous. To be fair I was using a cordless 5 1/2 saw which I've successfully used to cut up to 1 inch stock with no problem; it just didn't work well for plywood. So I went back to my variable jig saw with a fine blade and small rotation, for a slower but very precise cut. 

I've also built a rolling cradle for the boat, mostly to move outside for sanding and to make room in my garage. Below are pictures of the cradle with the bottom piece, initial stitching just enough to see some shape; and of the dry fit stem. So far so good.

A few notes about the design changes. The four pieces of plywood "just" fit. So close that I didn't know if I had enough room to create the transom doublers and other odds and ends pieces--not to mention any room for even the smallest mistake.  My other concern is I wanted to slightly increase the displacement. I ended up increasing the depth to 5" and shorted the length by 10% so it's now 12'6"

Other progress. I had many stem options including just stitch and glue, an inner stem, two part stem or a rabbited stem which is what I'm going to try.

Below shows the stem pattern.

On each side of the stem, I routed a 1/4 deep rabbet and then chiseled a bevel angled for each plank.

I made a few minor changes to the design...but I'll show that next time along with the plywood layout.

I ordered four sheets of 6mm Okoume from Edensaw woods http://www.edensaw.com/ which was about the same cost as other sources but I could pick it up in Tacoma without paying $40 a sheet just for transportation.

I ordered a gallon of Raka resin and its 350 hardener. It gets good reviews and easy to mix 2:1 ratio.To start off, I scarfed the plywood together into 2 4'x8'x16' sheets using 10:1 slope. I used a plane to remove most of the wood and finished with a belt sander and flat vibration sheet sander. As you can see the layers make a nice guideline. 
















I mixed up a couple ounces of epoxy, applied it to the feathered ends, let it soak in a few minutes. Next I mixed in some wood flour until it was like thin peanut butter and used a wooden fork put a thin layer on the plywood before joining the scarfs together. I held down each pair with a line of filled water jugs for two days.

What's it going to weigh?

Freeships will get me part of the way. It allows for input of material density and thickness which it combines with developed surface areas to obtain a total weight as in the table below.

 The rest I'll have to do by hand, or using excel, in this case. The cleats will do on top of the bulkheads to strengthen the plywood edge and give a good gluing surface. The support beams will be spruce or pine crosspieces to support the thin seat plywood--I'm going with a beam every 6 inches which is close to Skene's scantlings. Next is I'm going to cover the plywood with thin fiberglass weave two coats of epoxy and another layer just on the bottom with one coat for traction and to strengthen to bottom. According to my original Gougeon brothers Boat Construction a pound of epoxy covers about 35 sq feet, I've got 52 sq feet in the planking. Add long strips of wood for the inner and outer gunwales. I added a pound for the 4 bronze oarlocks I'm going to canalize off one of my rotted hulls.

Add it all up and wow! I'm at 71 pounds. Of course I haven't added the fiberglass tape on the seams, nor breast hooks and paint of course but 75 to 80 pounds looks realistic. Nice. 

Next time I'm going to show the plywood layout.