It's hard to tell from your description, but if this problem is entirely above the waterline it will have very little effect on performance. The Shearwater 17 has a short piece of deck at the bow. In the kit I built the puzzle joint for this piece was very ragged and difficult to join with the main piece. You might not have this piece in perfect alignment. Worst case, cut off the end of the deck, install short sheer clamps in the hull and glue a new piece on there. -Wes

It's 100% fixable if you split the stem seam between deck and chine with a sharp japanese saw.  Just rotate the twist out, then epoxy it back together.  A few spring clamps will hold it.  Then glue the deck back down. Done. 

Best of all, this fix is completely invisible in the finished boat.

Thanks, cutting the deck loose and re-epoxying took out 90% of the curve. There must have been a little curve when I glassed the inside of the hull, I should have supported the ends better while curing. I took care of the rest with the plane and sanding and am now pretty sure I will be the only one who knows what went on there.