8:1 scarfs shouldn't break just from handling. Scarfs have been around from, at least, the days of the Romans, and they wouldn't have lasted that long if they crumpled so easily.
A proper scarf demands a bevel be cut across the broad face of a plank to give good gluing surface so that the face of the bevel should be X times the thickness of the wood. If you cut your bevel any other way it will be weak.
You can line butt joints up any way you like but the eye will be drawn right to them if they are too close together. Why bother? it's no more work to distribute the butts randomly over the hull.

Hi all,

: After 3 months of work I'm finally laying my first strips on a Fire
: Star.

: I quite literally found it impossible to find full-length lumber.
: Local, internet, you name it. There was one possibility that
: would have doubled the cost of the project.

: So, I decided to scarf boards together as suggested in Rob's plans.
: Built the jig, and also built a clamp jig to hold them square
: and tight while drying. Did a couple boards at an 8:1 scarf.
: Glued them up with TB III and let them dry for a week.

: As soon as I picked them up they broke at the joints. All of them.
: The one that didn't break, when I ran it through the table sw
: each individual strip broke as it came off.

: After much searching, I figured butt joints would have to do. To my
: (admittedly faulted) logic, the end result is the same product.

: Sidebar: when I design and build things there are always
: compromises. As a matter of habit I generally try to turn my
: compromises into "design elements".

: One idea I had for a design element would involve lining up all of
: my butt joints in a line from shear down about 4". My
: (admittedly faulted) logic tells me this is not a good idea for
: structural reasons. A little voice also tells me that most of my
: strength comes from glass.

: Question #1: Will lining up these butt joints create a weak
: "seam" in the finished kayak? Like, will it break in
: half when I pick it up? Strap it to a car?

: I laid my sheer line to see what it looked like. I like it. What I
: did was cut several 2" pieces of strip and (permanently)
: glued them to the back of the butt joint. I can either sand
: these off or leave them in place and glass over them. Question
: #2: Thoughts? Leave in place? Sand off? Will they actually do
: anything to reinforce the joint? I rounded off the corners so
: they look like little pills and I think I could live with them
: in the finished boat if they do actually do anything.

: Like I said the line of butt joints will be from the sheer line
: about 4" down. There will be hardwood pinstripes running
: between the butt-jointed strips. No more than 3 butt joints will
: be lined up without a hardwood pinstripe between them. Does this
: help any?

: Anyone have any thoughts? Bill, I know you have no issues with butt
: joints. Rob, it's your kayak and I know you DO have a problem
: with butt joints. Anyone feel like chiming in? I don't want to
: do anything that will compromise the integirty of my kayak.

: Thank you,
: Darel