I got a better look at the concave area this afternoon when I unwired from the cradles and lifted the boat up a bit. It was a very gradual hollow from the bow direction, and more abrupt rise (drop) on the stern end, where it then ran out fair to the stern. Almost like a really long skeggy area. I struggled with whether to leave it alone or not thinking maybe it was supposed to be there. It looked funny from what I could see with the boat right side up in the cradles, but not so funny when I lifted it out for a better look if that makes any sense. Maybe my error was larger and more subtle than I thought, but the rest of the seam fits together nicely, so I don't know.

In the end, I shimmed it out from the inside and packed epoxy "dough" into the cracks. I'll trim off the little wedges later. It isn't 100% perfect, but I went and glued the seams anyway. I can smooth it up the rest of the way with a little bit of fairing epoxy when I do the keel strip later. I think it'll be fine.

I appreciate the guidance from everyone, and I am glad I did not try to plane and sand it out by removing more material. Sometime is *is* easier to put wood back on than to keep "cutting away at the legs trying to make the chair level."

: The Pygmy Arctic Tern (S$G) instructions seem to anticipate there will be
: trouble with the keel seam in the middle half of the kayak. They suggest
: you lay the boat's keel on a 5 foot long 2 x 4, while propping up other
: areas as needed to hold the kayak securely, and then stick large push pins
: from inside the cockpit area along the keel seam through the seam and into
: the 2 x 4. This assures that the keel seam remains straight and flat while
: the interior seam gets tacked and filleted. I think it's pretty important
: to keep that area fair!

: Here's a tip: Remove the 2 x 4 prior to launching and the boat will be easier
: to turn!