In the late 70s I shaped a lot of these types of Kneeboards, round square tails, round tails and rounded pin tails ( all single fins ). The one pictured had 6 curved channels. The boards were 5’7″ – 5’8″ long 22 ½” – 23″ wide…
The single fin driving it through its turns and holding it in the sucky tube sections. The fin itself ( pictured ) was called “A Greenough finger fin” and the template was given to me by Baddy Treloar on one of my early trips to Queensland. It flexed fantastically and you sprung out of your turns with a wip like effect. It was all about flying out onto the shoulder after a tube then laying into a roundhouse flexing the fin into a rebound off the foam.
Cool read. How did the bottom contours on those early boards differ from what your shaping now?
They varied from a rolled bottom with a vee behind the fin , to six curved channels that started approx 12″ back from nose and finished just in front of fin. Then i tried slight concaves either side of stringer directly under neath where u kneel. Most though were just flat bottoms with really foiled profiles.Today i like to put the ‘Freak bottom and rails’ onto the old school planshape with 3,4 ,5 fin combo and its dynamite!