2007 Westlawn/ Island Packet Yachts Design Competition: Clinker Construction

Fifty years into the age of fiberglass, wood still casts its spell on designers and builders alike. It's a remarkably versatile and adaptable material, and Richard Boult is just one of many to have explored its application in conjunction with modern materials and construction processes.

Key to Boult's technique is a CNC machine that would cut the hull strakes from panels made by scarfing five eight- by four-foot plywood sheets end to end. (In his design package he provided print-outs of how the strakes would "nest" on the panels.) The strakes are to be beveled, lapped, and glued with epoxy over forms which would include six structural bulkheads and frames CNC cut from plywood to accurately fit the inside of the planking. A flat keel strake forms the bottom of the hull, to which the garboard planks are to be stitched and glued and the connection reinforced with fiberglass and carbon-fiber tapes. Laminated hardwood floors tie the hull together in way of the keel and mast step, and carbon fiber tapes run longitudinally along the whole assembly, up and over the floors.

In Boult's method, additional hull stiffening between the plywood frames would be in the form of 2-inch wide carbon-fiber tapes laid to follow the contours of the planking, essentially taking the place of steam-bent wooden frames. However, the judges weren't convinced that this would provide the stiffness expected without the carbon fiber itself being laid over a frame-like form.

The keel is a hollow, welded-steel airfoil with a tenon extending from its foot through which two halves of a lead ballast bulb are bolted together. The foil serves as the water tank, its 34-gallon capacity adequate for a crew of two (and probably sufficient for a parsimonious crew of four) on the 600-mile passage proposed in the specifications.

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