By Tom Hunter, MFC

All design starts with three basic geometric shapes: the simple but strong low-volume triangle, the weak high-volume square, and the strongest middle-volume circle. The square shape will provide the area needed under the top, but is the weakest of the three basic shapes, so we need to keep the straight lengths to a minimum. Incorporating arcs of a circle add strength to the corners (shoulders) and the horizontal span across the bow (crown). Adding triangles to straight vertical lengths add side-to-side strength by making the base width larger than the shoulder width.

Tom Hunter, MFC, is owner of Clearwater Canvas Inc. in Bellair, Fla. He holds a B.S. in engineering from Northeastern University and is creator of EZ Frame software and author of “Frame Design for Boat Tops.”