WOOD BOAT BUILDING
Humans have been building boats out of wood for many thousands of years. Many assume therefore it must now be obsolete. Wood certainly does not lend itself to mass production the way fiberglass does. Wood does have some distinct virtues. It is light, even compared to modern building materials, and in terms of tensile strength is stronger per pound than common electrical-grade fiberglass. In terms of stiffness, it is stronger per pound than S glass, E-glass, and Kevlar. In terms of its total structural efficiency, it is better than all of these materials, including carbon fiber.
Thanks to the use of Kevlar and other high-tech building materials, reduced weight and speed doesn’t have to come at the expense of strength. Building lighter and stronger boats is a principle goal at Morska Zvezda.
Morska Zvezda hulls are constructed of fir stringers wrapped with diagonal layers of Bruynzeel plywood manufactured from mahogany. Three layers are applied to the bottom with each layer set at opposing angles for extra strength. Two layers are used on the hull sides for weight reduction. The plywood is formed and fastened to the longitudinal battens and stringers by a vacuum bagging process. The hull is then covered with a Kevlar and fiberglass mat and finished with fairing compound to complete the cold-molded process. Vacuum bagging assures even bonding and a fair outer surface, while eliminating the need to drive thousands of screws or nails to hold layers together while the epoxy cures and then remove the fastenings to plug thousands of holes.
Cold-molded construction technique duplicates the weight-saving advantages of foam-core hulls while adding the extra strength of a wooden hull. On glass boats, most of the hull’s weight is in the resin which is absorbed by the fiberglass. Because cores are made of wood instead of foam core, the inner and outer panels do not have to be as thick in resin and glass. The result is a stronger, lighter hull with a better glass to resin ratio.