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Return to the news 07 October 2019

Targeting aerodynamics

Brest Atlantiques Maxi Edmond de Rothschild Franck Cammas Charles Caudrelier

On 16 September 2019, the Maxi Edmond de Rothschild was relaunched after a few days on land for an express refit. On exiting the yard, one new feature didn't go unnoticed; indeed a fairing had put in an appearance on the aft beam of the 32-metre giant. This canvas structure spanning 32m2, an introduction that had always been part of the design penned by the naval architect Guillaume Verdier, is a first for an offshore racing boat of this kind. Beyond the highly successful aesthetic value, this innovation is the new hallmark of the pioneering spirit that drives the Gitana Team in its quest for performance.

 

It's a fairing located on the aft section of the aft beam which adds the finishing touch to the beam profile in the same way as a plane wing. This fairing was made of Oratex, which is a flexible canvas the likes of which you find on the wings of a glider or microlight. The aim of this addition is to reduce the drag, by pulling the flow of air tightly around it, and consequently to gain both speed and performance.
“Over recent years it's become standard to have a fairing on the forward beam, which is supported by the trampoline. However, it's fair to say that it was a first on the aft beam. Furthermore, the gain is at least as significant as you can get on the forward beam,” explained Franck Cammas.

Put to the test offshore and in the open ocean

“Ultimately, the major work on the fairing consisted of finding the right balance between structure and weight, so as to make it hard-wearing. Our specifications were that it has to be capable of doing a round the world,” explained Sébastien Sainson, head of Gitana's design office.

In fact, this type of fairing has become common practice on the America's Cup boats, but it's the first time that an offshore racing team has put in place a structure of this kind on a boat dedicated to the open ocean: “Godzilla, the multihull with which the Americans from Oracle won the Cup in Valencia, was the first to brave this new development. After that, all the AC 72s and more recently the F50s in the last Cup were equipped with them. In our case, it's more the implementation and the realisation which prompted studies, because contrary to the America's Cup boats, we cannot allow ourselves to dismantle or redo the system every evening. As a result, our challenge centred on solidity as we needed to come up with a structure capable of withstanding days and days of sailing at high speed. The timing seemed right to us, especially as the addition of this fairing has no impact on the reliability of the Maxi. If it were to be damaged at sea, that would of course be regrettable, but it would have no influence on the intrinsic performance of the boat.”

Reduction of drag, gain in performance

For over two years, the Gitana Team has been breaking new ground with the Maxi Edmond de Rothschild and clearing the way forward for the still little-known technical aspects related to flight in the open ocean and high speed. Though the tests and simulations are initially digital, nothing will ever replace the reality of sailing offshore and the elements for checking and backing up the studies. In this way, the coming weeks of sailing and in particular the Brest Atlantiques and its 14,000 mile course, will provide us with a definitive validation of the pertinence of this innovation in terms of gains.

“Theoretically, this aft beam fairing is a real plus for the boat, particularly as it considerably reduces the drag. Studies show that there are significant gains and now we're in the process of finding out if that's actually the case! Above all, we're observing how the Maxi Edmond de Rothschild handles because often on a computer there are no waves, gusts or unexpected heeling… What we can say from our initial observations is that this new feature changes the boat's attitude, making it a little more spirited, a bit more flighty. We need to see how it holds up in boisterous conditions and over the long term, before we can draw a proper conclusion regarding performance,” admitted Charles Caudrelier. 

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