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Time for a truce?
Designer Gino Morrelli is growing concerned about how ‘high performance’ these high-performance multihulls have now got... As designers of high-performance catamarans we get called upon to design or upgrade ever more powerful performance racer-cruisers. As a result, we have been privileged to be in the front line of an increase in large (45-70ft) multihull participation in coastal and day race series worldwide, and particularly in the Caribbean islands races – while also enjoying the camaraderie fostered by these events. We are also seeing (and have been actively involved in) an escalation in the arms race to build and turbo-charge these high- performance cruisers, to the point where they rival the performance of some dedicated raceboats of just a few years ago. As a point of reference, during the 2016 Caribbean circuit the Gunboat ocean cruisers Tribeand Elvis, with their mix of family plus a few profes- sional crew, were on more than one occasion finishing in front of the fully professional team on the VO65 Brunel. Exciting, yes. But the direction of travel is beginning to be a concern to us. We believe it is time to call for a truce. So this article is our attempt to advance an idea that we believe will ‘improve the breed’, benefiting the owners of these impressive machines and the multihull industry in general: the creation of an internationally accepted handicap rule for these sophisticated performance yachts. The evolution and improvements in mainsail materials and battens over the past 10 years have been dramatic. Fourteen years ago Morrelli Melvin (MM) originally helped conceive and designed the South African- built Gunboat 62 and 66 with sailplans that featured pin-head mainsails. These sails had moderate roach, supported by full-length battens, but terminated in a conventional 10in-wide headboard. As sail technology evolved to the current state of more powerful – often carbon – fat-head sails, those small headboards have been replaced by horizontal heads that are nearly 12ft wide! Expressed as a percentage of boom length, mainsail head widths expanded from 3% to some boats now sailing with 45%. These fat-head/square-top mainsail improvements drove owners to purchase these new sails, to immediately improve their boats’ light and medium air performance. In the case of a typical Morrelli Melvin-designed Gunboat 62/66 this lowered the hull flying speed from 24-25kt true wind speed (TWS) to approximately 20-21kt TWS.
54 SEAHORSE
Once the engines (mainsails) became turbo-charged it became necessary to change the wheels (daggerboards) to handle this increased power. Using the Gunboat 62/66s as an example, as originally conceived, the daggerboards on these designs were not exposed above deck when raised, due to aesthetic considerations. When fully lowered the shorter daggerboards were supported beneath the deck at the sole level and at the bottom of the hull. These boards worked well enough with the smaller, less powerful pin-head mainsails. However, with the adoption of fat-head sails the under-deck shorter boards could not harness the power of the new sails. So due to our recommendation, and design assistance, these boards began to be replaced with much longer, stronger, higher-aspect (and more costly) daggerboards, now supported at the deck and keel, along with more sophisticated bearings. These enhanced board systems were expensive, but the return in perfor- mance was significant. And with the additional traction the hull flying speeds were lowered yet further...
Concurrent with these changes, improvements in batteries, electric winches and hydraulics were employed on the boats to help handle the increased power. But these powerful systems have been disguising today’s huge sheet loads behind the push of a button. The physical effort involved now only rears its head when reefing and manoeuvring, but even then it remains largely disguised by the improved technology.
As an example, I recently sailed the Gunboat 62 Elvisusing a handheld wireless remote to control the hydraulic mainsheet and the electric winch-driven main traveller… while hull flying. A brave new world.
The net result is that the boats are now much faster upwind and down. The hull flying speed has decreased further to the point where a MM-designed Gunboat 62 turbo like Elvisin race trim now flies a hull, with a full hoist fat-head mainsail and self-tacking jib in just 14kt TWS. And this is a boat that was conceived for fast long-distance cruising.
In a similar case, we recently assisted in the completion of the MM-designed Gunboat 66 Extreme H2O, which is now being raced in California, designing enhancements that take the performance a couple of steps further. These include adding a giant masthead
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