Before I removed the old broken steamed frames I used a spilling board to pick up the outboard shape of each one.
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Then transferred the spilling to a lofting board.
Using a batten and spline weights to fair in the shape.
Blocks cut to fit the line and eventually held down with screws put through the board.
Laminates glued with epoxy and clamped to the blocks.
Two ribs Port and Starboard can be made from the same spilling.