RACING DOWNWIND

Spinnakers symétriques et asymétriques de régate

Les voiles qui dernièrement ont plus évolué ce sont les voiles de portant. Aujourd’hui, grâce à l’évolution des matériaux, des études et des techniques de fabrication, les spinnakers sont beaucoup plus efficaces qu’auparavant, et permettent de naviguer jusqu’à 45° du vent apparent. Des essais comparatifs entre bateaux identiques ont permis de déterminer que les peformances au portant sont une fonction de la forme du spinnaker aussi bien que de sa taille. Cela est surtout vrai lors qu’on navigue plus haut qu’en plein vent arrière.
OneSails offre une gamme complète de spinnakers de haute performance pour la régate. Chaque dessin est individuellement optimisé sur le bateau, une garantie du rendement maximum.

Le logiciel de dessin utilisé pour la conception tient compte du poids du bateau aussi, afin de mettre en rélation optimale les volumes de la voile avec ceux de la coque. Notre équipe de dessinateurs est toujours disponible à discuter avec vous quel serait le bon spinnaker pour vos exigences: leur grande expérience qui va de la Coupe d’Amérique jusqu’aux pétits monotypes vous garantit qu’ils auront toujours le bon conseil. Notre but final est celui de vous aider à extraire les meilleures performances de vos nouvelles voiles: le guide ci-dessous « faster off the wind » vous donnera une idée de base de quelle voile est mieux adaptée aux différents angles de navigation au portant.

SAIL VIEWER

Power-reaching has always been a highlight of offshore racing but more sailors are now also looking beyond those up and down inshore courses

There is nothing more exhilarating in offshore sailing than power- reaching – the point of sail we dream about that makes the other legs of a tough race worth the pain... High speeds, spray and that visceral thrill we get knowing a boat is being pushed to its limits as the miles are speedily devoured. A drawback on this point of sail, however, is the heeling and imbalance that can happen when there’s either too much force on the sailplan from the masthead Code 0 (MH0) or even the fractional Code 0 (FR0), resulting in costly sometimes brutal course deviations to hold on to these sails. Yet the speed and power are hard to give up, even with the extra miles covered – while constantly recalculating the VMG trade-offs against a lower heading.

Often the only way to stay high enough to stay on course is to reduce the power and heeling moment by dousing the larger sails and shifting down to smaller headsails. But then there is a significant loss of power and speed, with more of the mainsail needed to maintain drive force. Using more main means shifting the load balance aft, which in turn results in more helm pressure to stay on track. The more main used, the more weather helm needed, and the greater the rudder angle which creates drag, inhibiting speed further.

The result is often a ‘void’ for the otherwise well-equipped offshore racer where the sail inventory is simply not optimised to get the best speed at the desired angle. The latest-generation ocean greyhounds chasing course records know this and have been designed with their masts well aft, creating enormous foretriangles in which to fly multiple combinations of headsails and staysails, often mounted on furlers for easy deployment.

Not all of us have the luxury of reconfiguring the entire boat – mast position, sailplan and appendages – just to accommodate a larger foretriangle and remain competitive in other sailing modes. But we can find speed in reducing heel while retaining power in the sailplan.

OneSails has been working hard on this problem. Paul Eldrid of OneSails in Perth is gearing up for the Austral summer season, and examining how to power up a variety of fast designs ranging from a Bakewell-White 36 to a HH42, DK 46, Carkeek 47 and several TP52s. All show benefits from new reaching headsail designs from OneSails. When given the space to operate efficiently, flying multiple headsails will not only provide more power to better balance out a fully trimmed mainsail, and reduce drag from the rudder, it will also stabilise the flow across the whole sailplan.

‘Fortunately there are no restrictions in IRC and very generous headsail allowances in ORCi that allow for development of these sails to fit an important niche for the passage racer,’ says Eldrid. ‘We have made several discoveries in this process that we think will really re-energise these boats in reaching conditions.’

Rather than the traditional arrangement of tacking a reaching headsail at the bow and then trying to fit in a genoa staysail somewhere on the foredeck, Eldrid has been experimenting with putting the larger headsail out on the end of the bowsprit (called the J0), giving plenty of room to fit another headsail aft of this, such as the new square-top jib staysail (the JS).

Many of us are used to course racing, where headsails all carry battens... this is not necessary with these reaching sails since the depth is further aft and leeches do not need to be straight, in fact they should twist for optimal flow. With no battens, furlers then become a strong option for more boats.

Optimal combinations of the headsails, reaching spinnakers and a reefed or full-hoist main are many and varied. Mindful of cost, OneSails is now developing ‘turbo-charged multiple headsail solutions’ that still use the niches of the MH0 and FR0 but now supplement them with new sails including the J0 and JS.

Up until now OneSails has been building these sails in panelled construction as they test mould shapes at full scale. However, the company’s design and R&D teams are also conducting a fuller Fluid Structure Interaction (FSI) study to provide the data to start using its continuous yarns one-piece 4T FORTE composite membranes to optimise for strength and weight.

‘Already we’re seeing a strong interest in bringing back the fun and thrill of more efficient reaching on all courses,’ says Eldrid. ‘This is an exciting new development path.’

RACING SYMMETRIC SPINNAKERSRACING ASYMMETRIC SPINNAKERS
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Pourquoi choisir OneSails

1. Technologie exclusive.
Depuis plus de 10 ans, Onesails a développé des technologies exclusives pour faire de la voile en une pièce à fil continu une réalité pour les bateaux de croisière et de régate.
2. Performance.
Les caractéristiques des voiles comme le poids, le contrôle de la forme et la résistance à la déformation impliquent de meilleures performances comparées aux voiles à panneaux traditionnelles.
3. Qualité.
Les membranes M3™ et 4T FORTE™ sont fabriquées exclusivement en Europe dans un seul et unique établissement afin d’assurer un strict contrôle du cahier des charges de la production.
4. Conception.
Une analyse permanente et l’expérience acquise sont les atouts indispensables à l’amélioration de l’élaboration des meilleurs produits. OneSails, au premier plan de l’industrie de la voilerie, investit continuellement dans la recherche et le développement afin d’assurer la production des meilleures voiles possible. Le succès de cette approche est confirmé par le nombre de trophées remportés par les clients OneSails sur de nombreux championnats nationaux, internationaux et mondiaux.
5. Service.
Toutes les voileries OneSails doivent apporter un service de première classe dans le conseil et l’assistance aux clients. Pour cela, chacune d’elle tient à sa disposition une équipe d’experts à même d’assurer cet engagement. Outre le nombre croissant de voileries principales, le réseau de distribution s’est enrichi de centres de services placés stratégiquement le long des côtes partout dans le monde.

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