New mast technology for Safran
A new ballast system, a new titanium keel, and now a new mast with a 3D woven carbon mast track - brand new to the world of ocean racing: Marc Guillemot's Safran is innovating once again, bringing together expertise from within the Safran Group and from outside. The weight savings and improvements in terms of performance and reliability are now said to be huge.
"This new mast is the result of a lot of different people working together," explained Guillaume Verdier, designer and person in charge of the construction of this new 28 metre long spar. "The real innovation is on its rear side, with a 3D woven carbon track, formed in the same way as Jacquard cloth is produced and which will withstand the strains, differently from a traditional track. That means we have been able to make weight savings high up and offer improved reliability thanks to this process and to a completely new way of looking at the attachment points. This innovative work from the team was only possible thanks to the resources within the Safran Group and Hervé Devaux’s HDS engineering team, who went over my static calculations again and again. With the calculations and designs, together with the architects that work alongside me, Romaric Neyhousser and Hervé Penfornis, we have spent a lot of time over several months to come up with this innovation.”
The original idea was decided on at the same time as the change to a titanium keel foil, and the overall philosophy of this new mast was once agin to be lighter, offer better performance, be more reliabillity and with an overall cost not exceeding 20% more than a conventional carbon fibre mast. Guillaume Verdier explains: "We didn’t begin with a blank sheet of paper, as the initial choice was to keep the basic arrangement of the first two masts, in other words, it rests on the deck and has three sets of spreaders. We didn’t want to take any risks by completely changing the concept, with for example a mast with two sets of spreaders or a wing-mast, which are both more flexible and subject to dynamic forces. We gradually made headway working together: I was involved with the conception and design, Hervé Devaux at HDS checked my calculations, Bruno Dambrine at Safran offered us his experience of the 3D woven technology and then, there was also Snecma and Safran Engineering Services (subsidiaries of the Safran Group) working on dynamic calculations. Thanks to digital modelling and the means available at Safran, we were able to carry out simulations at each stage of the job concerning the behaviour of the boat and mast, for example, seeing what happens, when she slams into a wave. Thanks to that, we were able to identify strains in certain places that we couldn’t see simply by using static calculations."
These dynamic calculations, used by Safran in particular for their crash tests, are a new concept in ocean racing, and enabled the team to make further progress with this innovative mast. "We also included the data we already had thanks to the sensors measuring acceleration on board the boat, when she had her previous masts. At each stage, we knew if we were on the right track or if we had things to correct."
The actual weight savings are obviously confidential. But according to Jean-Marie de la Porte, Safran’s Project Manager, they are huge. "When you save one unit on top, you can take three times that from the keel bulb," explains Guillaume Verdier. "We end up with a boat that is stiffer, which cuts through the waves more easily, which pitches less, and so is faster."
Returning to the 3D woven technology - a process developed in the Safran Group - this involves weaving together carbon fibres using the same principle as on a traditional loom. This technology, used in the design of parts for the aircraft industry, means that it is possible to obtain mechanical properties, higher than traditionally available with carbon fibre. “The design of this new mast involved calling upon the services of experts within the Safran Group as well as from outside, and this was an extremely enjoyable experience,” stated Jean-Marie de la Porte. In the end, as with the two previous masts, it was built at Marstrom in Sweden.
As for the final result, skipper Marc Guillemot gives his impression: “There were two goals: reliability and weight saving, and so consequently improved performance. As far as the reliability is concerned, that is something we’re going to have to wait to judge, but in theory, knowing that we’re not going to see the mast track snap off thanks to the 3D woven carbon, that is something very positive. As for the savings in weight, that is something we can see already: it is a high percentage and the goal has well and truly been achieved.”
Out on the water? “What I felt since the trails has been confirmed: we’ve made considerable progress. We see that in every point of sail, particularly sailing upwind. Last year, as you might expect, we were lagging behind the boats built since Safran [PRB, MACIF, Banque Populaire, etc], but now we’re back up with them. Combined with the new ballast system and the new keel, this work we have done together is rather like pushing the reset button. For the moment, it’s very encouraging.”