Many Thanks for all of your help and suggestions.

I did unstitch the seam from the last frame to the stern, then I pulled,tugged, clamped, cussed, and flirted with my threshold of frustration while the shop thermometer climbed to 104. Try as I might, I just couldn't eliminate those wrinkles. So I decided to go for a different approach.

I resewed the after deck seam, with the fabric laying flat across the gunwales and as wrinkle free as I could get it, making no attempt to pull the fabric tight around the hull. Then I flipped the boat over and sewed along the keel, starting at the rear frame and working toward the stern, pulling the fabric tight as I went along. That worked great! Now I'll probably put a rub strip along the keel to protect that seam, but I don't mind that.

This sewing business isn't nearly as easy as Jeff makes it look in his video, but dealing with these challenges is what makes boat building interesting, eh what? Next time I'll know enough to heed Dave's advice and break out the staple gun!

Cheerio! Ronnie