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 All Novis spars employ a laminate of uni-directional carbon fiber, 45 degree biax ply and a 0/90 cloth to produce a multi-axis matrix designed for the specific loads of each area of the mast. This laminate matrix is also finely tuned for bend properties to match the characteristics of the individual boat. The resin content is strictly controlled through pre-impregnation of the epoxy resin into the carbon ply. The use of pre-preg carbon fibers from Gurit guarantees an optimal fiber to resin ratio, with some resin contents as low as 38%. To maintain their engineered physical properties, the pre-preg materials are then refrigerated and kept at low temperature until need for spar building.
The pre-preg carbon plies are precisely laid into female molds, with internal and external vacuum bagging used to pre-consolidate the laminate. Some mast builders are satisfied with this simple vacuum pressure to eliminate voids in their laminates. At Novis, however, we employ a specially designed autoclave to produce laminating pressures of up to 100 psi. This extreme pressure produces a laminate with the minimum possible void content, typically less than 0.25%. By comparison, vacuum lamination produces 1% to 3% void content and hand lamination produces a 5% or more void content. The elimination of voids is critical to provide greater strength in the spar. While under pressure the laminate is cured at 250°F, toughening and strengthening the carbon and epoxy composite to aerospace standards.
Through the use of female tooling, Novis is able to employ internal reinforcements producing a smooth and constant tube section. Male mandrels used by other manufacturers locate these reinforcements on the outside of the tube, creating unsightly external patches and bumps. Another advantage of Novis’ female tooling is the ability to laminate carbon backstay cranes which are integral to the mast tubes. These integral cranes eliminate the backstay to spar bond which can add unwanted weight to the top of the spar.
The patented Novis molding system also includes a molded recess for the luff groove system. This high density luff groove system is designed to accept low friction, ball bearing batten cars and intermediate slides, providing effortless mainsail hoisting and lowering. Those desiring maximum race performance can choose to use a traditional boltrope mainsail with our standard luff groove system. For low maintenance, spars are finished using Awlgrip premium topcoats. A clear finish is also an option on every Novis spar.
 By utilizing the unique properties of carbon fiber which has a tensile strength greater than steel, the mast tube laminate can be tailored to meet the various loads imposed on the rig. Conversely, an aluminum mast tube is extruded at a constant weight and wall thickness throughout its length and must be sized for the greatest loads which occur at the bottom panel. The result is an excessively heavy section, particularly aloft where weight most adversely affects performance and handling. For rigidity, Novis mast laminates are dominated by pre-preg uni-directional fibers that run the length of the rig and are locally reinforced in the bottom section, taking maximum advantage of carbon’s strength and versatility. The resulting laminate is light aloft and reinforced in the lower pane for greater strength. Furthering the carbon advantage, each tube is molded with a taper in the top section. Not only is the overall tube weight less than 50% of an aluminum tube, it also has a lower center of gravity which dramatically magnifies the performance advantage. This attention to weight reduction and distribution will make any yacht more stable. Saving 130 pounds aloft is equivalent to having four 180 lb pound crew members on the rail. The weight savings also results in less fore and aft motion in a seaway so more energy is translated into forward motion rather than uncomfortable pitching. Weight savings aloft will not only improve performance on the racecourse, but will also provide a much more comfortable sailing motion when cruising.
Once a product limited to America’s Cup yachts and high end custom racing boats, Novis Composites’ continual efforts to improve production techniques and decrease costs have made carbon spars a viable option on cruising and racing boats alike. Where a carbon spar was once a luxury that cost more than double its aluminum counterpart, Novis refined production techniques can make a carbon spar less than 25% more than an aluminum replacement.
For comprehensive Spar Assembly Instructions Click Here.
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