Evolution in the parallel profile surfboard construction system

There has been an evolutionary process with our parallel profile construction system, it started in 1995 as a very thin flexible balsa lamination of four multi directional layers all of the same thickness ( essentially a springy bent balsa ply sort of like a diving board or ski ). The next step was leaving out parts of the two internal panels, thus making a hollow structure, but still with 4 layers the same thickness. Then ( still with balsa ) we made the middle panels thicker than the deck and bottom panels, thus increasing the depth of the hollow internal sections.At that point we gave up using balsa and turned to redwood, pine, and cedar, so the system changed again as flat internal plank layers became narrow frames. Since then the system has become more varied, for thicker boards ( like SUP's ) we do up to four internal layers and the angles, thicknesses, and spacing of the frame and block layers varies according to the board.Recently we have started pegging the frame junctions with tiny vertical struts to maximise strength in terms of resistance to internal pressure ( although we do vent ).In addition to the construction details involved in the system there are numerous design features which we use, some of which are unique and intimately related to, or derived from the construction system. These are part of the wooden board building experience. Many people treat wooden board building as an exercise in reverse engineering i.e. reproducing a foam shape in wood. That is a legitimate approach but it's also interesting and productive to let the mateials and construction system lead the design . . . . for example the flex which can be had with wood.Here the parallel profile system has been adapted for a kneeboard 'spoon' which has an upper and a lower deck: