design wings work!nicolas goldenberg’s k8 sports is almost certainly the first modern monohull...

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We all know the benefits of wings over conventional sails.This now proven technology is commonplace in speedrecord designs and C-Class catamarans and has becomean unchallenged feature of the modern America’s Cup. At thesame time we have also learnt how impractical and expensivethese systems are for the everyday sailor. However, during thepast two years Advanced Wing Systems have quietly been goingabout an extensive R&D process to bring the advantages of wingsails into a soft or semi-rigid format that can be used on any boatand by any sailor.

Wing sail vs standard rigHaving experienced the 34th America’s Cup in San Francisco, weshould now need little convincing that wing sails are more

efficient than standard sails in terms of performance. This isbecause they are able to produce more lift with less accompanyingdrag, the forces being oriented in such a way that they producemore drive force and less heeling force.

The SRW – the first fully functioning semi-rigid wing Most wing sail attempts have been based on fitting a standardwing onto an existing boat or mimicking what we conventionallythink of as a wing.

These attempts have not been particularly successful; mostlythey are far from user-friendly, expensive and not suited for everyday boating. The SRW has reinvented the wing concept in amore pragmatic way – light, user-friendly, affordable and applicable to almost any boat. ��

Talented young Argentineandesigner Nicolas Goldenberghas enjoyed great successwith his RG 650 Mini 6.50.He is also not afraid to take on the perhaps morechallenging subject ofthe ‘production’ wingsail and its application

Nicolas Goldenberg’s K8 Sports is almost certainly the first modern monohull purpose-designed for a quasi wing rig. The increase in efficiency over a single-skin sail allows the K8 to rely primarily on form stability – meaning a smaller bulb and lighter displacement

Design

Wingswork!

SH Dec Design Hi res.qxp_S_H May Rob.qxd 13/10/2015 09:46 Page 47

The key factors of the SRW� Familiar set-up – no need to learn how to sail again� Simple – few controls and the sail can be stored and reefed asa conventional sail� Light – no complex structures are involved and weight iscomparable to a conventional arrangement� Increased performance – due to the wing sail configuration� Allows the use of headsails, jibs, code zeros and spinnakers

How does it actually workSimplicity is the key; our patented system is based around a specially designed and aerodynamically developed mast section.This section is allowed to rotate and is fitted with twin tracks that support two standard sail membranes. A further custom-designedspreader system, together with tapered battens with custom batten ends, plus a few basic but necessary control lines completethe package.

The two mainsail membranes are hoisted in the normal way,using one halyard that splits into two within the mast andattaches to the head of the ‘sails’. This also allows reefing in thetraditional way and at the end of the day the sail can be droppeddown and either flaked manually or, if you prefer, into a pair oflazy jacks.

The rotation of the mast section is the key to achieving the correct aerofoil sections. When counter-rotating the mast (forward face pointing off wind), the windward membranebecomes tensioned (hence flattening the surface) while the leeward battens and membrane are compressed (causing themembrane to bulge). See illustration B (below right).

Additionally, the outhaul control is used to induce camber asrequired (illustration C, right). Slip movement between the twomembranes delivers twist by controlling thickness and camber, asyou can see comparing illustrations D and E (right).

In short, the SRW provides a wide range of section shapeswhile only necessitating a relatively simple set of controls.

Next stepSoon after starting this project we increased the size of our development group, G Yacht Design (ARG) joining forces withAdvanced Wing Systems (AUS) and Katabatic Sailing (AUS/ESP),to pursue further development of the prototype semi-rigid wingusing an RG650 Mini 650 as our original test platform.

ConceptThis enlarged team then put their heads together to develop thedesign concept in terms of creating a purpose-built boat to bothexploit the AWS concept and also get something AWS-based intothe marketplace. After conducting a careful examination of current offerings, the K8 Sports was the result: a very modern 8msportboat suitable for a broad range of sailors, simple yet thrillingto sail and easy to transport. In time the K8 Sports may evolve asa one-design class, but in the meantime it is readily suitable forIRC fleet racing.

It should also make for a great little club racer, slotting intomost local handicap systems and promoting the capabilities of amodern yet pragmatic wing rig system. We believe that this flexi-bility of concept and application will deliver maximum technicalinterest and sailing enjoyment… all at an accessible price.

The K8 SportsIn terms of hull design, the K8 Sports was purpose-designedaround SRW performance parameters. This approach contrastswith the usual design spiral where too often a rig is designed tosuit pre-ordained hull parameters.

Consequently, our final hull lines differ from other existingboats of this size. The SRW rig delivers more power with less heeland, as a result, the hull has been given greater form stability thanwould be typical at this size, with relatively flat underwater sec-tions – that run right from the bow – to promote early planing.

The K8 Sports has more than met our early expectations duringinitial testing in Spain in September. Upwind the boat is stable andeasy to manage and is continuing to impress all who get hold of

the tiller. Powerful yet extremely manageable, the K8 Sports isachieving speeds comparable with much larger boats, opening thedoor for a very exciting product launch at the end of this year.

The K8’s exaggerated waterline beam – but with narrow heeledwaterlines – drove us immediately to employ twin rudders foroptimal control in all conditions and at all (normal) heel angles.

Downwind the hull is powerful and planes easily, enabling thehelm to catch every little wave. In larger waves and strongerwinds the bow lifts quickly,the boat behaving a little like askiff as it begs to be offered upfor the next surf.

The bulb keel lifts for trailing as do the rudders. Thebowsprit is also easilyremoved for transport. Thedeck design has been created

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K8 SPORTSLOA 7.99mBeam 2.55mDraft 2.1mDSPL 1,200kg Crew 3-5Wing area 29m2

Jib 12m2


according to the needs of the SRW rig plan, the standout featuresbeing the mid-cockpit (carbon) traveller beam and tidy moderncontrol pod. The correct traveller location is vital to getting themost out of SRW, as the sheet must work at the correct angles tooperate the wing efficiently.

The raised pod on the cockpit floor includes all the fine-tuningcontrols for the twin membrane rig, allowing the K8 to be operated by a small crew yet still achieve maximum potential. Thejib is set up with wider sheeting angles than you would see on asoft rig, to facilitate the correct interaction with the deeper chordof the wing compared with a traditional sail. A self-tacking jib set-up allows the crew to focus on wing trimming.

In terms of aesthetics, the K8 Sports displays a clean and modern look, featuring a large open cockpit and low streamlinedcoachroof. All of the sailing systems are kept simple and neat,with most control lines running through the inside of the boat topreserve a clean deck.

K8 – principal features� Semi Rigid Wing technology (SRW)� Built in E-glass with carbon reinforcement� Trailable (lifting keel and kick-up rudders)� For one-design and IRC racing� Crew weight limit allows for three to five sailors � Price including SRW and all sails – €95,000Nicolas Goldenberg, Buenos Aireswww.gyachtdesign.com www.advancedwingsystems.com q

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The twin membranes of the SRW ‘sail’ are clearly identifiable inthis K8 rig photo (above). By rotating the specially profiled sparthe span-wise shape can be varied to make the sail sectionsdeeper or flatter, as required; adjusting the outhaul and the slip between the membranes adds control of twist and camber.Top left: wing sail forces vs standard single-skin configuration.Left: a seamless transition of section shapes is made possibleby combining adjustment of mast rotation, outhaul and slip


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design wings work!nicolas goldenberg’s k8 sports is almost certainly the first modern monohull...

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