cross-section, surrounded by strands of carbon similar to those in ECsix that are bundled into an extended elliptical shape. In cross-section, up to 40 per cent of the carbon in the structure is in the carbon plate, while the remaining percentage is in the carbon strands.
Future Fibres’ strong composite knowledge and high technology processes allows these rods and the plate to be perfectly aligned and working together as one single element, bringing the highest possible stiffness and strength that current technology allows. This clever design then offers the impact resistance of the strand bundles of ECsix, its lack of vibrational nuisance and windage drag, and its flexibility for coiling and transport, yet also having the inherent strength and rigidity of a solid rod, all formed into the low-drag configuration of the extended elliptical shape profile. In a high- performance programme, this may be the best solution yet to minimise all elements of drag, both from shape and vibration risk.
Even with its non-circular shape AEROsix can be attached into existing ECsix fittings with the use of an elliptical adapter, so retrofits and repairs are no problem.
the elliptical shape were between 1.25 – 1.6 sec/mile and 1.9 – 2.5 sec/mile for the extended elliptical shape compared with the round shape over 8-20kts of wind, and reaching at an apparent wind angle of 75° the ellipses were less than 0.5 sec/mi slower compared to the round shape in the same wind range. This translates on a boat of this size and speed to be from 0.20 to 0.26 boat lengths/mile advantage at upwind VMG angles at 8-20kts of wind speed for the ellipse shape, and 0.30 – 0.42 boat lengths/mile advantage for the extended ellipse shape. At a reaching angle of 75°, the maximum disadvantage was about 0.5 boat length/mile in the same range of conditions. Future Fibres then used this information and applied it to a typical superyacht regatta such as the St Barths’ Bucket, where a typical upwind leg is 15.9 miles, the downwind leg 13.3 miles, and in the wind range of about 14kts where there is the least advantage predicted from shaped rigging. They found in this scenario the effect of shaped rigging to have an advantage of 19 seconds in the race for the elliptical shape and 30 seconds for the extended elliptical shape. Applying the same assumptions to a model racecourse the length and geometry of the Caribbean 600, these advantages may amplify even
Above: the results of wind tunnel research at the University of Auckland and VPP
modeling by Future Fibres and North Design
confirm the aero benefit of elliptically profiled
rigging over round-section rod. For a typical-length day race at a superyacht regatta, this translates to a theoretical 19 second advantage. For a two-day offshore race, the difference could amount to as much as 12 minutes. Right: bundled carbon fibre rigging has a larger cross sectional area than solid carbon
rigging with the same tensile strength
more: up to 12 minutes for a race taking more than two days. And while we all know there are many variables inherent to yacht races, think about the value of a 30-second advantage in a highly competitive superyacht day race, or 12 minutes in the Caribbean 600.
Another effect studied was the effect of a vibrating rod on drag, where earlier studies had found that for an amplitude of 25 per cent of the diameter the drag increases by 50 per cent, and at 50 per cent amplitude this increases to 100 per cent drag increase compared with a stationary rod. Anyone who has been onboard a boat with solid rigging knows about this effect, it can be felt and/or heard, and while it may be tolerable during a race, in a superyacht at mooring with the owner and guests aboard, this can be annoying at best.
This vibration effect does not seem to be as bad or noticeable with bundled rigging like ECSix, perhaps because the energy dissipates more readily among the strands. While the effect of vibration drag has not been directly measured yet as in the shape-drag study, Future Fibres has nonetheless found a clever new hybrid solution that addresses all these effects in one- design: AEROsix. This new product combines a rectangular solid IM carbon RAZR plate in its interior
SEAHORSE 73
Danny Gallichan, captain of the Reichel/Pugh Wallycento Magic Carpet3
, was an early adopter of AEROsix and has said, ‘we’ve had the rigging for three to four months now and sat through quite a lot of different winds, and I have not seen any of the vibration that was originally a concern for us.’ AEROsix brings us squarely into the next generation of composite rigging, with increased safety, light weight, low drag, easy installation and minimal vibration.
www.futurefibres.com
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