weight saving over standard battery types. These batteries will be quickly recharged daily with an impressive 6kW solar arrangement to reduce the carried fuel needed to power two 24kW synchronised generators. Full self-sufficiency while under charter is achieved by having the equipment needed to both entertain and transport the guests, as well as to re-supply when needed. Accordingly, the HH 88 has space for a jet ski, a 5.75m tender and dive gear to be stowed aft, with a large forepeak and foredeck lockers for sail and fender storage.
Advanced carbon composites Paul Hakes has spent a lifetime working through all the details of how to get the best possible laminates in carbon. Starting with the tooling, he focuses on rigidity and stability to preserve the intended shapes in the two-part hull tools, yet has built in the ability to be adaptable for different sized hulls. In this way, if a new client wanted a 77-footer rather than an HH 88, Hakes and team can to adapt the tooling rather than build an entirely new toolset. This saves not only on cost, but also time in a boatbuilding process that would otherwise be measured in years and not months. Hakes uses ‘female-direct’ tools, where the moulds are built in plywood and glassfibre, sprayed with a 15mm-thick tooling putty that is then milled using a 20m x 5m x 7m five-axis CNC milling machine before a final layer of gelcoat is applied. ‘The middle portions of the moulds are adaptable in length, so with this system we can not only have multiple releases of new hulls, but also remain flexible should there be a change in specifications,’ he says. For the hull, deck and structural parts special triaxial carbon weaves are sourced from a local supplier and infused under vacuum pressure with epoxy resin to get the perfect balance of penetration and adhesion in all the laminates. There are no voids or dry spots, nor over-saturation producing excess resin weight. This same attention to creating perfect laminations is given to all boats built by Hudson Yacht Group. For the HH 88 with its multiple deck layers and two hulls set under a generous sailplan, engineering the composites to meet both the static rig loads and also the off-axis racking loads was quite a challenge. The mandate to save weight wherever possible is strong for all performance catamarans, but doing so and not accounting for these complex racking loads would jeopardise the structural stability and integrity of this large yacht, even though it is not
Above: ample
bridgedeck clearance and long, slender waterlines demonstrate that despite the very
strong focus on luxury, offshore
performance and handling are still a primary
consideration for this new generation of offshore multihulls. The cutaway inner sides of the tran- soms create a handy pair of dinghy docks that allow guests to board more securely from a tender Right: the inside helm on HH88-01 will be similar in style and configuration to this HH66 but without the 66ʼs for- ward cockpit. Instead, the bigger yachtʼs sail handling
winches and systems will be on the flybridge where the crew have a better view of the sailplan
designed to fly a hull like some of its smaller brethren. In fact the HH 88 is designed to have no more than four degrees of heel to maintain the expected comfort levels but can still cruise at impressive speeds. This is achieved by the design and fabrication of five massive main bulkheads that tie together hulls and decks in one massive composite structure to accommodate the enormous racking loads that can arise in a multihull of this size. Rather than relying on compression posts to handle these loads, this style of structure is more reliable and, in the end, more efficient for its weight to tie together the complex loads. All of the modular parts are fabricated separately then brought together in a huge assembly jig where alignment is assured along with efficient bonding and continued adherence to those ever-important weight targets.
Cost and performance of foils The high performance-oriented boats in the HH product line rely on the very latest in curved foil design to produce the lifting force needed to reduce displacement and increase stability to balance the forces produced in these boats’ powerful sails. For the HH 88, however, due to its massive size there were other considerations in choosing the right appendages. First, there would need to be a significant reduction in weight and
windage of the hulls and superstructure to get the same proportionate performance and there was no interest in further compromise due to all of the luxury feature requirements in the design concept. Second, simply adding more sail area and a taller spar would not help much unless a significant increase was committed to the modulus carbon in the spar, and that too was deemed beyond the cost efficiency of the project.
Third, trying to design, fabricate and install similar curved retractable foils would also add significantly to the cost without much benefit in performance gain in a catamaran designed to not fly a hull at all. So, a short keel design for each hull was chosen that would not only reduce leeway at minimal drag, but also save a ton of weight and about half a million dollars in cost.
‘We did some VPP studies on the various options,’ says Hakes, ‘and were surprised to learn that the loss in performance was not only minimal – like 10 per cent - but this was primarily in only upwind sailing angles. An achievable speed of 20kts is not the same as 22kts, but neither is the massive additional cost and complexity. In all we are happy with the results that are nicely within this already ambitious design concept.’
www.hhcatamarans.com q SEAHORSE 65
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