I am building this exact boat right now, albeit rather slowly. I crated the curved deck beams by simply stacking the laminations (did all 3 at once), and clamping them down over a block of wood. block in the center, clamps at each end. this gave me a nice curve that is mostly in the center 12 inches, and the ends are relatively straight, so that when they're cut down to size to fit the boat they'll be even side to side. you could also build a curved form out of plywood and bend them over that. i used the survey drawing, simply measured the distance from the top of the gunwales to the top of the deck beam, subtracted the height of the deck stringer, and the thickness of the curved beams. this gives the height needed, i added a bit for springback (added 1.5 inches as a random guess, since i havent built curved laminations before). then just cut a block of wood to this height, did a test run without glue, and when that worked, disassembled, glued it up and left it sit for 24 hrs. springback was less than 1.5 inches, but i hsould be able to account for slight variance by either mounting the laminated beam lower on the gunwales, or adding a spacer at the top between it and the deck stringer. clear as mud?

hopefully this link to my thread works, no pictures yet as my web hosting is in transition but will have some eventually. http://kayakforum.com/cgi-bin/Building/index.cgi/page/1/md/read/id/227194/sbj/skin-on-frame-new-f1-build/