12ft Skiff Construction
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- Parent Category: Company Info
- Created: Monday, 11 August 2008 16:00
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Hull Construction
Van Munster Boatbuilding manufactures light weight, high strength, high performance skiffs.
The composite pre preg hull, foredeck, self draining cockpit and bulkheads components are manufactured from SP Systems SE 84 uni-directional carbon fibre pre preg's over Nomex cores. These components are vacuum bagged and oven cured at over 85 degrees Celsius. This construction technique produces skiffs of maximum strength for minimum weight. It is the same technology that would normally be associated with the construction of Grand Prix racing yachts such as America's Cup, Canting Keel Super Maxi or Volvo Ocean Racing yachts.
Van Munster Boatbuilding can supply individual components for kit assembly, bare hulls, foils, through to fully rigged race ready skiffs.
The Pre-Preg Composite
The Hull, Deck and front tank components are all laminated with SP Systems SE84 pre preg system. Plies of uni-directional Pre-preg Carbon fibre are laminated either side of a Phenolic-coated aramid based honeycomb core.
Pre preg Kevlar or carbon- SPRINT ( Resin infused pre preg) is added to the laminate in high impact and stress areas of the hull and deck components to build up extra skin thickness, strength and stiffness within the structure.
The carbon skins are bonded to the nomex core with a pre preg adhesive film, which ensures a high strength bond with consistent weight and bond-line thickness.
Pre preg materials consist of a pre Catalyzed resin system that is impregnated into fibre reinforcment.
Increasing the temperature of the pre preg epoxy reduces the viscosity of the resin system from a tacky malleable solid at room temperature to a highly viscous liquid during the processing cycle to a fully cured high strength solid structure.
During the cure cycle high vacuum pressure is used to further assist with resin impregnation into fibers and laminate consolidation by venting any entrapped air within the laminate. Vacuum pressure and temperature are carefully managed within the processing to control resin flow and viscosity. Any excess resin within the laminate is bleed into the vacuum bagging consumables pack.
The Epoxy resin is impregnated into the carbon fibers by machine, which ensures that pre preg laminates have a more consistent wet out and higher fibre content than can be achieved by conventional wet lay up techniques.
Carbon fibers are much stronger than resin so, logically the greater the proportion of carbon in a laminate the greater its strength. Correctly processed uni-directional carbon pre preg laminates have final resin contents as low a 35%.
Construction features
- Internal frames are composite Carbon fibre (high density closed cell) foam sandwich construction. They are vacuum laminated from the latest generation Ampreg 22, epoxy resin and then oven cured.
A moulded flange ensures maximum bonding surface between the deck and frame system.
Extra frames are installed to bring the hull up to weight. The reduced panel size between the frames increases strength and reduces twisting.
The carbon Centerboard case is bonded and glassed tabbed into the hull and deck. There are no troublesome joints or flanges within the case. Longitudinal and transverse frames help distribute the immense forces placed on this area of the structure under full load. The position of the centercase can be customized to individual preference
The new female deck mould allows owners the option of a spinnaker chute or standard bag system. The watertight compartments on all future boats will be pressure tested for leaks before the boat leaves the factory.
The mast step position and foredeck measurements are at class maximum aft to provide maximum stiffness to the deck structure.
Whiskerstay, bobstay and forestay attachment points are of Composite construction. The Composite chainplates feature a stainless pin system.
Composite carbon/Kevlar rudder gudgeons are laminated into the custom made clear carbon fibre sternpost.
Solid bobstay and Whisker pole sockets are foils shaped for minimum drag.
Bowsprit is all carbon for minimum weight & maximum strength.
Self tacking jib track system is recessed into the deck. The pre preg mounts are integrated into the deck mould for maximum strength and minimum weight. The shape and angle of the track has been optimized to allow the jib sheets and purchase system to be lead behind the spinnaker chute opening and run under the foredeck.
The spinnaker chute system is set up for a two, patch retriever system to minimize friction and reduce the risk of running over the kite during hoist and drops. A spinnaker sock keeps the kite out of the water in the cockpit. The large radius clear carbon chute opening behind the stem also helps reduce friction.
The twelves are the ultimate twin trapeze sailing skiff with a hull weight of only 45kgs, a 12ft waterline, 6ft beam and unrestricted sail area. The incredible sail area to weight ratio generates the most awesome acceleration with recorded top end speeds well over 20 knots. Going downwind at these speeds the small easily driven light weight hulls are constantly becoming airborne under their massive mast head asymmetric spinnakers. With a rigged sailing weight of just 75kgs most skiffs have an overall length (including the carbon asymmetrical spinnaker bowsprit and crew outriggers aft on the transom) approaching 26ft.
