I’m getting ready to install the rails, does the orientation of the scarf joints matter ,
I just installed the inwales/outwales on a CLC Lake Union Swift and had the same question. But in dry fitting them I became much more concerned about the bend they need to take to meet at the bow. Not sure what the curve is like on the NED, but it’s sharp enough on the Swift that I thought the wales might split. I thus stopped worrying about the scarf joint orientation and just went with the slight natural curve of the long sticks. (I also soaked them in pvc tubes which improved the flexibility.)
With six wale pieces total whose scarf joints are in random orientations, I don’t feel any specific orientation is sub optimal, either visually or structurally. But I’m no expert.
Orientation does actually make a difference for scarf joints. For maximum strength you want the grain patterns of the 2 pieces to be parallel. That way, force is smoothly transferred across the joint.
If the grain patterns are not parallel, they intersect and form a stress concentrator at the joint.
Fortunately, this effect is more apparent with traditional joinery and glues than with gap filling epoxies. The epoxy-filled gap smooths out the force transfer, eliminates some or all of the stress concentration and provides a high-strength bond that can handle any residual excess stress. So the orientation is not as critical as it would be with a tight joint and carpenters’ glue.
Laszlo
I prefer the outer scarf points to point aft. If that joint should encounter a foreign object such as a piling, buoy, tree, trailer, or something else while moving in the forward direction, you’ll have a scrape instead of a broken point. It also looks right, at least in my opinion. And of course, if you are planning a bright finish, prettiest sides go up.
Scarf joints should go on a boat like scales go on a fish. Is that the way I should have put it?