The All New Wave Chaser 390ZF

WaveChaser takes the planing concept to the extreme, combining the planing properties of windsurfers with the sail carrying power of a twin rig catamaran.

The new Wave Chaser 390 ZF hulls were purposefully modelled by Sam Tehan at Force 9 to achieve maximum hydrodynamic lift without loss of manoeuvrability. The hulls have minimal rocker, with slight “vee” through the nose, and a seamless transition from single through to double concave. Volume, width and rail height are measured to provide buoyancy, balance and support for Carbonix T Rudders and Z Foils.

The 2017 Barracouta sails are relatively narrow with a foot length to height ratio of 2.6:1, which allows for maximum airflow exposure to both rigs. The leech is tapered to a shorter head to reduce drag and allow for rapid point adjustments for improved acceleration and release. The luff curve is designed for optimum torsion and response from the SLAKE full carbon race masts. The power point, clew and boom pocket have been lowered to bring down the centre of gravity and manipulate air flow closer to the deck. The sails are made from ZZ 04 3.5oz Technora and Mylar Contender sailcloth and feature seven foam easily adjustable batten tension sandwich battens to keep the rigs as light as possible. We’ve developed two mast/sail combinations for the 390 ZF. A 560cm, 8m2 rig for light to moderate wind up to 15 knots and a 430cm, 6m2 for fresh to strong wind up to 30 knots.

Carbonix Founder & CEO Dario Valenza writes, When Nigel McBride approached us with his Wave Chaser project, he had a well thought-out brief and a concept proven on a working prototype. Our task was to refine the concept, design the mechanical systems and production/assembly methods, create tooling, and make provision for fitting and testing various optional foil packages.

It is really interesting to consider that Wave Chaser arises from a unique brief, outside any racing class rules, for a clearly identified purpose and market segment. Therefore it makes sense that the design does not resemble those coming out of traditional theatres of development. Instead the concept and layout are unique responses to the intended purpose, though the execution borrows tools and materials proven in competition. Namely, the requirements were for a demountable platform that could be stacked or car-topped conveniently, and also double as a pair of SUP boards for a couple to enjoy when not sailing. The planing boards are joined by a modular elevated cross-structure and powered by twin free-standing rigs using carbon masts and windsurfer style wishbone booms. Twin sails keep the centre of effort low, limiting heeling and pitching moment. Mounting the masts outboard allows the cross-structure to be relatively unstressed.

The hulls are made using a prepreg carbon/Nomex honeycomb sandwich, giving great rigidity for minimal weight. They incorporate a longitudinal stringer and partial bulkheads in way of the mast steps, but are otherwise unsupported, relying on the stiff panels of the shell monocoque instead. The cross-structure uses filament-wound carbon tubes connected via elbows and joiners which are custom made in closed metal moulds using internal bladder pressure to consolidate the laminate.

The carbon foil case and mast step mouldings are also made in CNC machined metal moulds to ensure accuracy and a consistent surface finish. They are designed for quick assembly and dis-assembly, as well as allowing adjustment for testing and refining the geometry. We designed and machined custom fittings for the rudder hangings and foil bearings, making sure these were light, strong, and easy to use. From the prepreg carbon structure to billet machined fittings, the overall technology and look borrow heavily from automotive racing and aerospace. The sails and rigging package, as well as the trampoline, incorporate lessons and techniques from the racing world, applied to the particular mission that Wave Chaser is meant to fulfil.

“The development process was all about balancing performance, durability, and cost. Many areas required careful consideration of competing factors to minimise weight without giving up toughness and without blowing the budget”.

Good tooling is a key factor since it allows the parts to come out with consistent dimensions so all the components go together well. However, arriving at shapes that could be tooled up for quick production and assembly required a long iterative process. For example, given that the hulls are essentially boards, without the freeboard of a traditional hull, it was necessary to raise the platform to get wave clearance on the trampoline. However, raising the entire platform would have negatively impacted weight, windage, and aesthetics. So the outboard joiners were made with a 2D bend to give an upward kink to the outer ends of the crossbeams. This solution is elegant but was only possible with good understanding of how to reliably mould complex shapes in tooling with non-planar parting lines. Similarly the mast steps and rudder hangings had conflicting engineering requirements that had to be resolved. Commonality was important to reduce the unit cost of each fitting. So all four trampoline foot attachments are identical, and the gudgeons on both sides are also the same.

Performance is expected to be geared toward stronger wind as the flat bottomed boards do carry a wetted area penalty. But the idea of Wave Chaser is to take it out and have fun when the wind is blowing. In the light stuff you can go SUP instead!

Similarly, the low-down power delivery of the twin rigs and high righting moment should allow the boat to be driven hard in breeze.

Wave Chaser is not expected to be an upwind/downwind, velocity made good, machine. Instead it is made to be a blast on a reach when properly powered up.

Wave Chaser is about versatility, modularity, and fun, executed via a high-tech toy!