(Source: Carbo-Link) After achieving a third place finish in the first leg of the Volvo Ocean Race and without any issues with their Carbo-Link supplied rigging, it is time to have a close look into the details behind Groupama’s Carbo-Link Rigging package.
Groupama 4, designed by the Franco-Argentinean architect Juan Kouyoumdjian, was optimised by the Groupama sailing team’s research office based in Lorient, built at the Multiplast yard in Vannes and equipped with a mast manufactured at Lorima in Lorient. The lateral rigging, spreader with spreader bars, tangs and fittings are produced by the Swiss Company Carbo-Link; a company specialized in design, development and production of structural elements for high loads.
All fittings, tangs, spreaders and details Carbo-Link developed for Groupama are custom designed and unique. “We use the Volvo Ocean Race to develop state-of-the-art parts that, later on, will be used for more common racing, cruising and superyachts. The Volvo Ocean race is the toughest and the most demanding playground for the rigging industry. If your product and ideas survive here, you can recommend them with a clear conscience to all your clients”, reports Dr. Andreas Winistörfer, CEO of Carbo-Link.
And indeed, by having a deep look to the rig and rigging of Groupama 4, the progress and innovations made by Carbo-Link and the team of Groupama can be seen:
Lateral Rigging: With a spar supported by just three spreaders, rather than the usual four, Groupama 4 stands out from her rivals. The vertical cables are made of solid carbon and are continuous from deck to the Cap Tang. The cables are tapered at each section which means that the stiffness at each cable sections exactly achieves the stiffness required by the designers. The diagonals are fitted to the verticals at the spreader tip, resulting in the most aerodynamic and tidy solution. The length of the diagonals can be adjusted by a custom made, internal titanium tang system hidden within the mast (Fig. 1).
|Fig. 1: Adjustable internal tang made by Carbo-Link|
To reduce the drag even more at the spreader tips and at all fittings, Carbo-Link cables are elliptically shaped locally and aligned to the expected true wind angle.
|Fig. 2: Small and tidy solution at spreader tip of Groupama 4|
Headstay: The headstay is made as a carbon rod. Scores of tests showed that even aluminum hanks are no problem for the solid carbon forestay. To allow bending at the top and bottom fitting when the headstay is not tensioned, spherical bearing terminations are applied.
Bobstay: Even the bobstay is made as carbon rod. To fit perfectly between bowsprit and hull, the tolerance of 1mm had to be fulfilled.
eRigging: The V1 and D1 as well as the headstay are equipped with eRigging developed by Carbo-Link and presented for the first time at METS 2010. The new load measuring system is internally installed in the cables as can be seen by a small electrical wire coming out of the thimble (Fig. 4). The team of Groupama will be able to measure and control the strains and loads in the cables in real time during the whole Volvo Ocean Race.
|Fig. 3: eRigging installed in D1, V1 and headstay|
End fittings: As a novelty in the composite rigging market, Carbo-Link developed metal free thimbles for the vertical cables gaining in an impressive weight reduction. The whole end fitting is a laminated part. A ball within the laminated thimble compensates for small misalignments. The performance of this solution was tested within Carbo-Link’s 150ton Fatigue test machine.
|Fig. 4: Metal free thimble with implemented strain gauge developed by Carbo-Link|
Chain plate design: To get rid of heavy and bulky turnbuckles, Carbo-Link’s designers provided a new chain plate design to be able to tune the rig by changing shims in the chainplate (Fig. 5). Since carbon rigging shows no creep, the lengths do not have to be changed once they are tuned.
|Fig. 5: Chain plate design with shim to adjust lengths|
Spreaders: The spreaders (Fig. 7) and spreader bars (Fig. 6) where laminated with prepreg fibers by Carbo-Link’s Formula One experienced Carbon fiber specialist. These structural elements of the spreader where made from high modulus carbon fibers to achieve outstanding structural properties. The whole spreader is cured in a one shot cure resulting in a minimum of secondary bonded joints all around the wing profile.
|Fig. 6: Spreaderbar of Groupama 4|
To protect the forward part of the spreaders against chafe of sails, halyards and other lines passing by, an in-house developed chafe guard was installed.
|Fig. 7: Spreader of Groupama 4 with chafe guard|