I used exactly the same lumber from Home Depot for my first and only SOF so far. I had exactly the same concerns as you share and got similar answers. I made a but(t?) joining and compared to a scarf join of similar length. Waited for both to cure (using Titebond III) then set off to break the two. The butt-joined sections obviously had increased stiffness and when bent, the wood just outside of the butt piece broke due to the stress the edge of the butt piece put on the stringer. The scarf-joined pieces just bent as if there was no joining. I bent that scarf a lot and it did not break - I figured in my kayak it will never bend as much so I just used it.

I did not want to have to make 2 scarfs per stringer just to avoid having a scarf near the cockpit - scarfing took some time and needed certain precision so I wanted to avoid that work if I could. So I finished the kayak with a single scarf on each of the 4 equally thick stringerrs - these scarfs fall in the front of my cockpit.

I've tested the kayak (18 feet, almost all of it waterline) in some wind chop (up to 2 feet) and in white water with waves and currents (Class II) that does stress the frame some. No problems at all.

The problem with that particular lumber is that the 1x2" is actually something lile 3/4x1-3/4" so the frame is rather skinny. I felt if I drilled holes for things like rigging or lashing it would weaken the frame a lot. So I did not drilling - all was lashed only (except the bow and stern boards, where I used glue and a couple of small dowels each).

I also have an extra chine compared to the Yost single chine design. That and the center keel are made from the same scarfed 1"x2"x8', except each is cut in two along its lengh so it is half the width. I think the frame came out stiff enough and if I had used the thinner variety skin rather than the heaviest, the kayak would have been closer to 30lb than to the 40 it is now.

: I discovered that my local big box store (Lowe's) has "Premium
: Eastern White Pine" boards, 1"x2"x8'
: (.75"x1.5" actual). They're clear. I actually found a
: couple that were straight, too. ~$4 a pop, which works out to be
: a lot cheaper than the 16' lengths of WRC I was looking to pick
: up.

: Unfortunately, that means I'm scarfing the lengths together. Just
: for giggles, I picked up a couple tonight. Measured and cut a
: 8:1 scarf rough with my circular saw, then cleaned it up with my
: block planes. I had some Gorilla Glue laying around, so I
: slapped a thin coating on one side, lightly wet the other, and
: clamped the two together. I figure I'll let it cure overnight,
: then Gorilla Glue three 1/4" dowels through the joint.
: Either it adds to the strength or my peace of mind.

: Now, the questions, from everybody who's more experienced than me
: *shameless grin*.

: - Am I ok placing the scarf at the middle of the two pieces,
: which'll place it right around the cockpit? Or would I be better
: off doing two scarfs per stringer, placing the joints at ~8 ft
: from the cockpit?

: - What's the opinion on Gorilla Glue for scarf joints? I clamped
: the Hades out of the joint... even broke out my Dad's old
: *****BIG***** C clamp (see the Picasa pics below). I'm not
: worried about clamping force, but I'm wondering if epoxy will
: give me a stronger joint. I've used Gorilla Glue plenty on my
: model aircraft, but there's a huge difference when I'm actually
: riding in the kayak (versus watching the model go down into a
: corn field). The scarf joint itself wasn't perfect... one side
: was perfect, the other was off by 1/64", maybe. Just enough
: for me to tell there's a gap there. I've heard GG requires a
: really good joint to be secure.

: https://picasaweb.google.com/theluckyone17/Kayak#