After being convinced of the quality of the keel superstructure mockup we decided to go ahead and cut out the keel side plates. At first, tracing the curve seemed tedious. Joosep took vertical measurements of the keel profile every 10 cm or so. Then cut out the shape. It was satisfactory, with a precision of 1 cm or so. Then we recalled how Doug Jackson of svseeker.com drew the curves on his steel plates – put a pencil flat on the curved surface, place the joining plate onto the curve and trace with the pen – 95 % match of curves.