The transom is interesting because the plans specify that it be canted 5 degrees forward, instead of just in parallel with the form frame. To accomplish this, I clamped a batten parallel to the edge of the form frame, and dropped the plumb bob down from the end of it, hanging over the hull. By measuring how far the plumb bob was from the angle point, I could use the Law of Cosines to determine far the point under the plumb bob had to move, in order to rotate the batten onto a 5 degree angle. Here's a picture of the setup:
This was taken after the batten was rotated from right to left and is already in the final position for the transom. There's probably easier ways to accomplish this placement, but this seemed to work out okay. Then it was taping time:
I didn't know about or even remember the Law of Cosines -- I was just pretty sure there'd be some piece of trig magic that would work, but it took about fifteen minutes of hunting around on Wikipedia to to finally find it. :-)
Also, you can see that I've left the transom full-width, rather than cut it down the middle. I wish I could do that with all the bulkheads -- frankly I'm not looking forward to making the bulkheads match up, during hull join.
After the transom, I worked on trial-fitting the aft cabin bunktop. This took awhile because for some unknown reason, the bunktop center line was higher than the hull center line by about 1/2" - another unexplained mystery: