In order to get the bottom battens straight along the frames, I will mark their positions with the frames temporarily fixed to the strong-back (jig). The strong-back is just a very big “saw-horse” from a length of 190 x 45mm (945 x 225 micro-furlongs) and some supports made from 90 x 45mm (3-1/2 x 1-3/4″).
In the pictures, the frames are only clamped onto the jig. There will be keys (slots) cut into the strong-back at each station. The depth of these keys will be different at each station so that the bottoms of the frames will be level for the keel.
The next task will be to build the transom and the stem. The strong-back will need a couple of additional bits of timber to support the transom. For the stem, the jig needs to be cut back (see the curved pencil line in the first photo). I will not cut this off until I have constructed the stem.