Are 60ft trimarans unseaworthy?

The Daily Sail got the views of leading trimaran designer Nigel Irens

Incredibly the main reason that Irens says the organisers should investigate the weather is that he believes 60ft trimarans cannot survive the ultimate storm conditions. One reason for this is that each of these beasts has a 100ft tall wingmast with a cord of 600-850mm. In the biggest cases this represents almost 26sqm of area that can be feathered but obviously cannot be reduced.

In the severe weather it was not the wind, but, as ever, the waves that were the main problem. With a series of fast moving depressions passing to the north of the fleet the wind direction was shifting between northwest to southwest and back causing a terrible cross sea. In these conditions Irens believes the skippers were left with few options.

"We’re reconstructing where the real centres of trouble were and that group in the south east were just completely wiped out," he says. "And the difficulty seems to be that if you are a skipper when the conditions get that bad, you can’t really survive.

"In 60-70 knots and with all these changes of wind direction you get situations where you have pyramids of water where the waves are crossing. And if you happen to be unlucky enough to get where one of those ferocious cross seas takes place, there is not very much you can do about it.

"The difficulty has been that they [the skippers] have been between a rock and a hard spot - if you try and stop the boat you become very very much a target in terms of things that can go wrong with the structure - the structure is very severely disadvantaged when the boat is dead in the water."

Irens says he isn't aware of too many occasions in the past when 60ft trimarans have hoved to. "Hoved to is, certainly as we’ve seen, not a safe condition when the seas are that bad. We really need to get the feelings of the skippers, but the word is so far, that it is pretty hell when you try to do it, because you are taking such horrible seas in a way the whole structure wasn’t designed to take."

Irens believes it is safer to continue sailing. "Funnily enough, it is easier for the structure, because you don’t have this phenomenon of the windward hull being hit and the mainhull even becomes less target because it is lifted out of the water somewhat. But obviously you can’t give it some welly if doing so means that you capsize..."

But even that isn't practical for a long period for a singlehanded sailor.

During the race several boats out to the southeast were caught out and ended up sailing under wingmast alone.

"The only hope really is to try and do what you do in a dinghy and kind of feather the whole boat and keep it moving at 2-3 knots, but it just becomes impossible because you can’t see where you’re going, you can’t steer and you’ve got to sleep sometime," says Irens, adding "If it just drifts off by a couple of degrees and starts to set off and changes the apparent a bit, then it could be over before you know it."

"So at the moment I can’t really see a way out of those very extreme conditions. The next question is how often do they come? As we have seen the monohulls tended to be more out to the west and everyone who was west and northwest was better off than everyone who was in the south and the southeast."

The severe conditions highlighted new problems in the designs. Remarkably the problems were consistent between the different designs. The van Peteghem/Prevost trimarans had problems with their beams. In most cases the beam fairing was stoved in, but in the case of Jean le Cam's Bonduelle it was more serious still - one of the uni-directional carbon fibre bands was destoryed by wave action.

But for two out of three of the new Irens tris matters were far worse. Both Loick Peyron's Fujifilm and Karine Fauconnier's Sergio Tacchini broke their weather floats between the two beams.

"The structural failures of masts or these fairing problems, I think they are classically the product of big seas and not much boat speed because you can’t get the main hull lifted up high enough to avoid the impact. And sadly the thing that is revealed to us that caused the outside hull to break is that this clearly from a structural point of view is a disaster because with the outside hull in two pieces there is no structure left…"