It is driving me nuts...finished the hull of a cedar strip Cosine Wherry and trying to put some wooden bars across to hold the transom and bow seats.

Just have to cut the ends of a 1 1/2 " x 1 1/2" x 16" piece of spruce to meet the contour but if i cut it to the 16" i need then of course the bottom of the wood hits the curve of the hull where i want the top to be....i tried one suggestion of inserting a pencil in a block of wood and trying to run the block all around the spruce but i of course run into the same problem...i tried using a smaller scrap and then to transfer the lines but its no good either.....can anyone direct me to a video of this....i fear words might not suffice...thanks