God's battens

Fraser Brown gives us the full, in-depth explanation about why C-Tech rectangular battens are the best in the world

With the 41 40-60ft multihulls and monohulls now into countdown mode for the start of the Transat Jacques Vabre, a technological development that could go some way in differentiating the winners and the losers in the biennial two-handed transatlantic race is in the field of battens, or so Fraser Brown would have us believe.

Brown, a Kiwi, has been lurking around in France over recent years, acting as shore support or crewing for the younger Bourngon brother, Yvan, during the Rexona Men trimaran campaign (remember the waterskier?). He is also part of Tracy Edwards' Maiden II crew and last year was on board the 110ft catamaran's 24 hour record as well as their Round Britain & Ireland record.

Aside from his racing credentials, Brown is now the European face of C-Tech, Alex Valling's Auckland-based company that is currently revolutionising batten technology.

"The way these battens developed was because of the America's Cup going to New Zealand," explains Brown. "When the boats went down there it became apparent that there was a reasonably large hole in the market for battens that could do the job on a Cup boat, that would be light enough and stiff enough to produce what they wanted as far as sail shape was concerned.

"Alex went down to the boats and had a look at what they were trying to use, went back to his workshop and designed a male mandril idea that tapers progressively towards the luff of the sail. He made this male mandril quite long and made it out of pure carbon so you'd have no movement in it because he was using an autolave to cook the laminate later."

At the time AC battens tended to be poltruded fibreglass or carbon fibre rods, as used in the construction industry, with uniform bend characteristics, their shape controlled by the sail. Vallings came up with a rectangular-shaped batten with a number of unique characteristics. Because it was built over a tapered male mandril the batten is hollow and thus lighter weight than a solid rod. The weight-strength ratio was also improved by the construction of the battens using a mixture of uni-directional fibres running down the length of the battens sandwiched by layers of unis laid at +/- 45 degrees. For added weight reduction the fibres were laid up using pre-preg and cooked under pressure in an autoclave.

The stroke of genius was both the tapering of the mandril, allowing battens of all sizes to be made (just start laminating nearer the narrower end for smaller battens, etc), but also being able to dictate the bend characteristics of the batten according to the section and the amount and type of fibre used in the laminate.

"He would position the start point of the laminate for the batten at a particular position to suit the stiffness and position where the maximum camber was required for what the America’s Cup boats wanted," says Brown. "For the America's Cup he had to go into so much detail to produce the battens that Alinghi and Team New Zealand wanted that he learned a huge amount about maximum position for camber and stiffness and what is heavy and what’s not and how much material is required."

Prior to the Cup Vallings was working with Team New Zealand and three of the challengers. Then realising the value of his product Alinghi bought him exclusively, although C-Tech were still allowed to supply Victory Challenge. "So with the America’s Cup battens, after a load of development a complete set ended up only weighing about 10kg," says Brown. One of the discoveries they made was that for the same load case the bigger the section, the smaller amount of laminate was required to achieve the required stiffness - the exact same maths that goes into mast design.

While these battens represented a breakthrough in Cup boat technology Brown with his intimate knowledge of the French sailing scene figured they would be perfect for the 60ft trimarans and the Open class boats.

In addition to the benefits of lightweight and being able to match perfectly the bend characteristics of batten to sail (and vica versa), the C-Tech battens have a much higher degree of indestructibility.

So far they have broken no battens in Europe, says Brown. During Alinghi's entire campaign in Auckland this time they broke just two. "They said it is just unheard of," says Brown. "And of course the AC guys went as light as they possibly could and they broke them when they wrapped them around the runners or the capshrouds. Because they were so light they couldn’t take the impact. But obviously for offshore use we change the laminate."

Brown cites several examples of where batten breakage has demolished boat's chances during offshore races. "If you look at Bonduelle [Jean le Cam's 60ft trimaran] in the Challenge Mondial, he broke all his battens and dropped right out of the race. Sergio Tacchini [Karine Fauconnier's 60ft trimaran] was the same - they broke all their battens and they have now gone to our battens.

"With the Maiden program last year when we competed for the Round the Britain record we did a gybe in 30 knots and broke six out of seven of the battens - image a line from the end of the boom to top of the mast - and we had to continue that record with broken battens because we didn't have the time to drop the main let alone enough gear on board to repair six out of seven battens. We had to finish that record with the roach of the main just falling over whenever we did a manoeuvre. After we broke those battens we had to do about eight or nine gybes and because of that we ended up destroying the main - it was too expensive to fix and by the time we’d finished the record the battens were sticking out through the main and you couldn’t drop the main because the battens were getting stuck in the lazyjacks – so it was an absolute major. If you break a batten on the maxi cats or the tris you just have to fix it because eventually it will work its way through the sail, and then you'll be struggling to drop the sail."

Brown believes that had they not broken the battens then they might have saved 2.5-3 hours on the Round Britain record. Just six weeks later when Brown sailed this same course on Steve Fossett's PlayStation during their attempt they beat Maiden II's time by just an hour...

The reasons for the indestructibility of the C-Tech battens, says Brown, is twofold. Firstly there is the sandwich of +/- 45deg uni-directional fibres to add torsional stiffness to the battens. Then there is the shape. "The ideal shape for a batten is a rectangular shape because if you hit a runner with a round batten all the impact is take on the apex of the circle," says Brown. "If you hit the runner with a rectangular-shaped batten you have got that whole surface area to take the impact. So the impact resistance is a lot great with a rectangular-shaped batten."

One of the best endorsements of the C-Tech battens in the offshore world came when Yvan Bourgnon was out training on board his Rexona Man trimaran prior to last year's Route du Rhum. During this the mainsail's top three battens were C-Tech. "He goes away solo for his testing and training to use the battens and do some hard gybing basically to try and break them," recounts Brown. "He wound in the Cunningham as hard as he could, eased the mainsheet and the traveller and put the boat through an extremely bad gybe. When he put the mainsail though battens 4-5 broke at the luff and ours, the top three battens, were just fine. He still to this day can’t believe the top three battens survived what he did." And this was the first set built to go offshore using numbers that Brown had guestimated from the battens being used in trimaran sails at the time.

Obviously the potential for screwing up gybes when sailing short-handed is even greater than with a full crew, however Brown says there is the opportunity for a major increase in performance too.

"What happens with the Open 60s and the trimarans is that when you want to do a gybe is - say if you are running with one reef - you’d drop down to number 2 reef to do the gybe and you’d pop the reef out after the gybe. So the whole manoeuvre ends up being a huge effort. And on a trimaran or an Open 60 two handed if you can get away without having to reef for the manoeuvre, because you are confident your battens aren’t going to break…



These are two parts of one batten, showing the degree of tapers. This is an America's Cup batten (no6) of the type that might have been used by Alinghi

"With an Open 60 if you’ve got the 3/4 chute up with one reef in the main and you want to gybe then you’ve got to snuff the chute, probably put a reef in, then gybe the boat gently and then pull it all out again. What we are trying to achieve with these battens is to not have to reduce the sail area - that they are actually going to be able to go through okay. So that is a huge time saver on a race like the Jacques Vabre - if the guys have the confidence that they can throw the main throw and they’ve got a product that is two thirds lighter than before."

One of the boats using C-Tech battens is Michel Desjoyeaux's Geant trimaran. "He told me that when he won the Vendee Globe in PRB, he broke a batten before the start in a gybe! So he started the Vendee Globe with a broken batten in the main. He is extremely grateful for this technology for this boat now," says Brown.

A stiff batten also makes for more reliable power from the main. "The thing with the sails is that when you are sheeted on and you are driving the boat hard in big waves, as soon as you hit a wave, your mainsail is trying to compress and if your mainsail compresses and makes it fuller it makes it harder to steer the boat," says Brown. "So if you have got nice stiff battens and it is stopping the mainsail compressing between leech and luff then it is holding the sail a lot flatter and it is much better for sail shape and driving the boat.

"The other thing that we’ve found is that the leech of the mainsail is a big area where you trim from and if you have got a good stiff batten in the leech then you can stand the leech up a lot harder and hold the top of the sail a lot harder with these battens. So as soon as you ease a little bit of mainsheet to twist the top off it can actually hold the mid-leech sag of the main and you can twist the top by using a bit of mainsheet." Most of this was learned during Vallings' period developing battens for Cup programs.

Through Brown's knowledge of the offshore racing scene, he and Vallings developed a new composite batten together using both carbon and S-glass (also available as a pre-preg material). "So we’ve now got two types of batten: one is a pure carbon batten, specifically orientated towards the tris, because they’re got a tall mast, small boom high aspect ratio sail, and they can continue with very high boat speed through a manoeuvre, like a gybe, and with the Open 60s, we’ve done a carbon/S-glass blended batten to suit the boat for races like the Route du Rhum, Vendee Globe and Jacques Vabre."

Both are made the same way - using the male mandril - the different construction is due to the application. "Because of the Open 60 rig set-up with quite a long boom and quite a big heavy roach on the sail and the style of racing the boats - two-handed and solo - we've tended towards the carbon/S-glass batten for these. The weight saving is incredible – it is about one third of the weight of the standard fibreglass poltruded rods they’ve been using." He says that previously skippers were taking the hit weight-wise using poltruded rod - some laminating unidirectional on to the outside of the rods to improve stiffness - just to improve their confidence in the battens through added durability.

This year the C-Tech battens have gone through a further development to make them acceptible in France. Here most boats use an Antel batten receptible which is designed to accept a round rod batten rather than a rectangular one. However following their work with Geant, Brest/La Rochelle-based loft, Incidences, have been so taken with the batten that they have come up with their own luff receptible especially to fit the rectangular section C-Tech battens. The first boat to fit the new Incidence recepticles this year was Vincent Riou's PRB Open 60, winner of the Calais Round Britain & Ireland Race.

Brown gives an example of how being able to engineer their batten accurately has helped Michel Desjoyeaux. "Initially, with the Geant sail we did a lot of work with Incidences to get the first set of battens looking good. During the development progress we went through for Geant we did battens 2, 3 and 4 from the top of the main and I went sailing with them before the Lorient Grand Prix and we were sheeted on hard and flying both hulls upwind and when you looked up the sail then no4 batten was a bit knuckle forward, soft in the luff. So what we did was when we finished off the sail with the batten, we changed our laminate schedule slightly to push the draft further aft to stop the knuckle-forward characteristic of batten number 4. And now as a result of that and development throughout the year Michel has changed the mandril size and asked if we can produce a sail that is slightly fuller in the luff to push the draft back even further and which is helping the mainsail to gybe and has created a slightly bigger mandril to make the batten even lighter again. So we’ve gone through a big development stage with Michel and he is now a long way ahead of the other trimarans, who are only catching up now."

Every C-Tech batten also comes with a bar code, that represents what batten it is, when it was built, for what boat, and obviously the stiffness and maximum camber and the position of maximum camber. "When we had that discussion with Michel [Desjoyeaux] about his number four batten this year, we just quoted this number, and Alex looked back at his laminate schedule and goes ‘okay, we’ll just change it slightly for the next set.’ So that how accurate it is," maintains Brown.

While the battens are most well suited to big boats, Brown says they have made battens for 18ft skiffs (again, still hollow made around the mandril) but thinks that in reality the smallest they will go to are Farr 40s. "Obviously it is the bigger boats that are harder on the gybes that are benefiting from this construction."

They have got into making leech battens and have supplied them to Neville Crichton's Alfa Romeo, but Brown says these would be suitable for smaller boats. The leech battens are a carbon/S-glass composite - with the S-glass in the leech. " S-glass bends more and because you need the tip to be quite flexible on the leech of the main, but the leech to be quite hard, it is a tricky one to build. I’ve done a lot of work this year with some of the local Farr 52s that have a couple of full length battens at the top and leech battens down the rest of the main and currently Alex is developing that for next season."

It is unnecessary, believes Brown, but they are shipping their battens particuarly for offshore use, sheaved in a Kevlar braid. "That is so that offshore, if you do break one then you can pull it out okay and it won’t damage the sail on the inside because it will all be contained by the Kevlar sock. We were also advised by the sailmakers that because race boat owners have had so many problems with broken battens that you won’t stand a chance selling them without a Kevlar sock over them. For a boat like Maiden, the next ones we do we will have a Kevlar sock because there’s no reason not to - it doesn't add any weight and it’s a great way to finish the batten off nicely."

Aside from Geant, for the Transat Jacques, the C-Tech battens will be on numerous boats of racing-winning potential from Sill to the new Ecover. Beyond this they would be an obvious choice for the new Volvo Ocean 70.