This is a model of the ‘Botter 4’ design for a vessel measuring 11 X 3.8 X 0.9 metres from the 1963 book, Dutch Yachts in the Future by H Kerksen, Sr..
I had the page of lines drawings shown here copied and enlarged to the required full size model length of 700 mm overall, making the scale 1:15.7
The modelling challenges are the tight curvatures in the hull, the inward angle and curvatures of the bulwarks, the inward angle of the curved cabin sides, together with the double curvature of the cabin top.
The first thing was to accurately shape the centre line spine from well seasoned, stable mahogany, as shown here on the full size lines drawing, before drilling end on to accept a propeller tube to enable the propeller to be rotated by hand.
The frame shapes were then each traced from the lines drawing, the tracing paper temporarily stuck to plywood, cut out, and glued on the spine as shown. Two extra blocks fitted with threaded inserts were glued in place at this stage to accept the threaded ends of the final brass mounting pillars.
The first layer of planking was simply fore and aft, and the second layer effectively diagonal in narrow walnut strips to closely suit each hull curvature as shown.
It was very important to precisely define the exact position of the strakes forming the interface of the double curved cabin top and the shaped inward leaning cabin sides - in order to give in effect a smooth three-dimensional ‘curve’. To this end a brass jig was made, and used at each frame to achieve the required accuracy.
Other photos show the foredeck with winch and mast lowering wishbone, the port leeboard, the Dutch gaff, the cockpit, tiller, rudder, and mainsheet.
The first layer of planking was simply fore and aft, and the second layer effectively diagonal in narrow walnut strips to closely suit each hull curvature as shown.
The cabin construction also used a shaped centreline spine concept together with frames traced from the lines drawing and cut out in plywood.
The first walnut planking layer of the cabin top shows a white wider shaped infill due to double curvature. The second planking layer used narrow strips of walnut.
– and finally the builder to set the scene of the final model.
