The decision last week to postpone the start of the Transat Jacques Vabre for the 60ft trimaran fleet given forecasts of 50-knot winds posed serious questions about the hardiness of this increasingly light and powerful fleet. Foremost in the minds of organisers and crews was the scourging experience of last year’s Route du Rhum, in which five trimarans capsized and seven suffered serious structural damage. One of these, Loïck Peyron’s Fujifilm, broke into pieces and was destroyed.

After being salvaged, similar types of failures were found. Designs by Nigel Irens and the team of Marc Van Peteghem and Vincent Lauriot Prévost both suffered, albeit in different areas. In the year since, the reasons have been investigated and these trimarans have been modified and strengthened.

Nigel Irens talked to Yachting World’s Elaine Bunting about the work done, the changes that are being made to temper development in this class, and about why – and how – the race programme should be changed to harden the class for offshore racing.

“At the end of the Rhum everyone felt the need to put their heads together. The designers had a couple of meetings in which everyone put their cards on the table, which was a healthy sign,” Irens says.

“Last year there was a bulge in new boats being built and a wholesale move towards building in pre-preg carbon and Nomex core. Everybody had drifted towards this technology and although the stuff’s been around for a long time, what went wrong was the result of that. There may be a big learning curve now underway and it may be that some people won’t use these materials again. We certainly haven’t used them on Ellen’s boat [her new 75ft trimaran, currently building in Australia]. We’ve gone back to more traditional core material.

“Basically, what it’s all about is the materials have very adequate static strength and there’s no problem in terms of sheer pressure head. But in reality what’s appears to be happening is that there is not enough capacity to absorb the loads that the skin sees. These are much, much higher than was the case with a softer, more forgiving material.”

This potential weakness was exacerbated on the Route du Rhum, when boats were hove-to and leaning heavily on the leeward hulls, which were repeatedly being slammed into waves. What made it all the more catastrophic, says Irens, is that failure of this type of structure spreads very quickly. “It’s a very localised sort of wave impact or slap that causes the damage. But because the material is very rigid, the rate of propagation of damage is very fast.”

Since then, similar cracking has been found on the outside hull of the recent Van Peteghem/Lauriot Prévost-designed Belgacom, caused during the qualification sail for the Transat Jacques Vabre. This suggests that the damage seen during the Route du Rhum was not merely the result of a one-in-a-thousand combination of wind and sea conditions.

Future designs will benefit from taking a step back to more elastic materials, such as cores of linear Airex, but the options for remedying the problems of these trimarans were more limited. “Obviously you can’t change the core so what you’ve got to do is decrease the panel size and make it even stronger. We also added a number of new frames,” says Nigel Irens. All the Irens designs that share the same outside hulls have been modified, namely Sergio Tacchini, Bayer CropScience and Biscuits La Trinitaine./www.ybw.com/img/newsdesk/yw/ywnews/0SergioTacchini.jpg”align=right> 

The crop of failures has nevertheless tarred the fleet, particularly internationally, where the ORMA 60 class has always lacked appeal. But Irens is at pains to point out that this is, to a large extent, the price of a development class.

“There’s a lot of evolution involved with all these boats. There are things that are learned over the years that are often learned through things failing, that’s fundamental. Normally every year a certain number of things go wrong and get put into the equation. There isn’t any way you can simulate some situations; you need empirical information and that gets fed in to the equation.

“In a situation where all learning comes through damage and through things going wrong, there will never be a 60ft fleet that can arrive 100 per cent intact, no more than there will be a Formula 1 race in which all the cars arrive at the other end of the track. I think a 20-30 per cent drop out rate is the way it is in a serious offshore race and if you don’t like the way it is, take up sponsored tiddlywinks.”

Having strengthened the latest boats, how much more robust does he think they will be? “It’s hard to put numbers on it,” Irens replies. “The amount by which you reinforce it is pretty much arrived at by estimate. A 50 per cent improvement would be good, but it’s easy to overkill things. You could go round increasing safety margins everywhere, but the trouble is if the boat was generally heavier it itself would be subject to greater loads; you would be back on a spiral of escalating efforts and escalating loads. You have to decide where to stop.”

At the same time as this voluntary comparing of notes between designers, the Offshore Racing Multihull Association, or ORMA, have amended the rules specifically to exclude less dependable materials or riskier developments. For example, from 1 January 2004, the ultra high modulus carbon M55J will be outlawed to try to address another problem in the fleet: distressingly regular dismastings.

Nigel Irens explains: “People were using very high modulus carbon and it wasn’t working. If you take a pure compression case, the higher the modulus of carbon, the higher the loads it will stand – until it goes out of column. But unfortunately that’s not the end of the story. There is a lot of pure bending that comes into it because, apart from anything else, there’s the cantilevered bits [on the canting masts] and the dynamic loads as the mast pumps around in strong winds.

“If a mast with very high modulus materials in it can’t afford to bend without breaking then that’s a problem. For the rigging to work properly it has to have bent a little bit before the rigging takes up the slack. So you’ve got a situation where the lower rigging is not really able to contribute what it should do.”

From January, the class association is also outlawing the canting rigs that have been a feature of all the new boats and is limiting the total foil area to 1.8m2. Larger and more powerful elliptical foils have become the norm and this limitation should nip in the bud what, for some, is the most worrying facet of development.

“That was most dangerous trend for my money,” comments Nigel Irens. “If you use a lifting foil near the forward beam, if you make that too efficient and start lifting too much you start going very fast but you get out of control – it’s got no pitch stability at all. You can get round that by putting another on the back in an attempt to fly the whole boat on foils, but by its nature it’s very expensive to do and risky.”

The new 1.8m2 maximum is typically the combined area of the foils currently used on the outside hulls, so it will be impossible in future for designers to add tail fins without eating into that allowance, he adds.

“What’s important is that the technology of the boats be controlled,” he says. “We want to be able to create a situation where the results are more sailor dependent and less technologically dependent. And partly because there is a snowball effect: the higher tech the boats are, the more expensive they are. The other aspect that is terribly important in the context of developing offshore boats, is that if they are more complex they are in the hangar much more often and that is absolutely anti-training and anti-development.”

As well as reigning in technology, Nigel Irens would like to see a change to the programme for the ORMA 60s to provide sailors with more opportunities to toughen boats and their own offshore skills.

“The ORMA class does have this rather unusual requirement for doing inshore and offshore racing. My feeling is that it needs to be reviewed,” he says. “The regattas they have are not that easy to sell to people anyway and whilst I think one or two in a season might be fine, personally I would like to think that all the other short events should be microcosms of an offshore event. They could almost be seen as a programme of testing or working up for the big ocean races of the season. It would demonstrate commitment to the fact that the object of the exercise is to make rugged, ocean-going boats.”

What kind of events would meet those requirements and how would it work? “It would be very interesting to have a set-up where, for example, you had a base somewhere like Quiberon and you raced round, say, Belle Ile, a 20- or 30-mile course, round a buoy outside the village. And if you flood-lit that buoy, I could well imagine a 24-hour, two-handed race which would be extremely tough and capture the real need for endurance capabilities,” he suggests.

“It would not only be an exciting race but a perfect training ground, so that it doesn’t become such a drama when people have to do it for real offshore. It’s in the nature of things that it’s only when you are racing that you put the pressure on to the extent that you need to, to test things, and [on these courses] if there is bad weather and things go wrong the boats are accessible.”

Until there is international interest in the fleet, and therefore some national rivalry and rooting instinct, Irens believes that endurance racing is the only reasonable rationale for the fleet and rule-making should reflect that.

“It’s how this sort of racing was born and why the interest was created. The public are interested in the man or woman against the sea, and the need to tough it out and come through unscathed is what fascinates people.”

That said, he thinks some of the worst Atlantic conditions should be avoided. Asked if he, like many others, thinks transatlantic races crossing Biscay in November – or indeed the relatively early season Transat from Plymouth to Boston next May – are incompatible with the class, he answers:

“Yes, I do. Even from a purely commercial standpoint having starts that have to be postponed is not good news. And every year we see the same thing, where October is OK and we get to the end of November and it’s this kind of weather. So it seems that we are asking for trouble.

“We have to remember that a few generations ago people didn’t go to sea in winter at all. You could say that the modern world has been guilty of collective arrogance and previous generations have had more respect for the sea. If you just take the attitude that ‘Oh, we’ll just make it stronger’ you are, in a way, ignoring the reality of what the sea is all about.”