A designer's perspective

ABN AMRO designer Juan Kouyoumdjian shares his post leg one observations

Here in Cape Town seeing in the Volvo Ocean Race arrivals, Juan Kouyoumdjian was a happy man. The Argentinian designer was sharing the glory of the first and second places of ABN AMRO One and Two, the two Volvo Open 70s he and his team back in Valencia designed, as well as the cream on the cake - a new monohull 24 hour record set by ABN AMRO One. There is an ancient truism in the Volvo/Whitbread race that the boat winning the first leg goes on to win the race. Another is that Farr designed boats always win overall (they have won overall ever race since Sir Peter Blake's ketch Steinlager II was victorious in 1989 - Pierre Felhmann's Farr-designed UBS Switzerland won on elapsed time in 1985 but the Briand-designed L'Esprite d'Equipe took handicap honours). This time round one of these two pieces of Volvo Ocean Race lore looks set to be broken.

While obviously pleased, Juan K was not being overly bullish. "It is quite significant - we could not have asked for more," he said of the ABN AMRO team's performance on leg one. "But it’s still a long race to go and what happened to the other boats on this first leg could happen to us tomorrow, but so far we seem to be in pretty good shape."

From a designer's perspective Juan K says the results in the first leg had further verified his VPP tools. "We predicted an average boat speed for the first leg of just under 16 knots and it was 15.95 and our prediction missed Noronha by three hours and Cape Town by two hours. So we were very happy with that. The boat sails the calculated polars almost spot on, it is amazing, we definitely have a good tool there."

After their torrid performance at the in-port race in Sanxenxo race pundits were rating the ABN AMRO boats as the heavy weather performers, the Farr designs as being the light weather weapons, the different designs reaching parity somewhere in between. Thus the first leg of the Volvo Ocean Race, traditionally a relatively light affair compared to the Southern Ocean legs, was not supposed to be one of optimum conditions for the Kouyoumdjian designs.

In fact Juan K refutes the pundits' view on the ABN AMRO boats: "The optimum conditions for the boats is reaching in 12-18 knots of wind. That is what we designed them for, contrary to what most people think - that they are heavy air machines. On this leg there were two times when they were reaching - once in 14 knots and the other time in 16, one just before Noronja and the other after they did the turn to Cape Town - when they started to pull away from the fleet quite significantly. So I am very pleased about that."

Kouyoumdjian reckons that the ABN AMRO boats are a weapon in these moderate wind strengths, while in less than 10 knots the Farr boats are faster and rather than being definitely faster in anything more than 18 knots the ABN AMRO boats are the same or slightly faster in these conditions depending upon the wave state. "The difference is in 12-18 knots because you are going from underpowered to powered and if you manage to keep a sail for longer than another boat and so forth that is where we seem to have a little edge," Juan K says. The last leg also proved that the ABN AMRO are 2-4 knots faster downwind in 20-25 knot conditions.

A new load phenomenon the ABN AMRO boats have been experiencing (as have all the VO70s) and which Juan K says represents a new load case in the Volvo Ocean Race, is downwind slamming. Upwind slamming is a well known, whenever a boat goes over a wave and slams back down. Downwind slamming isn't.

"This is new due to the speed of these boats," explains Juan K. "The boats go downwind flat or with very little heel and they go faster than the waves, so they keep on jumping from one wave to another and then when they fall into the next wave they fall onto a place on the hull which is slightly forward of the mast. This means that when they fall the bow tries to continue to go down and it bends a bit like the old karate chop thing. So if you are going downwind you have the spinnaker, but the bow is not sustained because there isn’t forestay tension."

As the bow is still airborne over the front of the wave when the slam occurs, it wants to continue on down and this puts the hull just forward of the mast in compression and the deck in tension - the opposite of what happens in an upwind slam. In fact this phenomenon isn't new - it also occurred in the Open 60 and 50 class, when after some delamination and core shear was identified as being due to upwind slamming, so designers Groupe Finot for a while built the forward underwater sections of their boats in monolithic carbon fibre (ie without a core).

Dynamic loads such as this are hard to quantify continues Juan K. "The old fashioned way of engineering these things is that you analyse static cases and you apply safety factors to them, but these boats have dynamic loadings applied to them that are so big compared to what we are used to that sometimes it is difficult to handle it through the safety factor method, so you have to get into some kind of dynamic modeling which is very difficult to do. Then even if you manage to do that you have to have the right inputs and it is a complex thing. But this is what 'Grand Prix' is all about: breaking new barriers in yachting."

Juan K is extremely impressed by the record runs - first of ABN AMRO Two in the opening 24 hours of the race and then by Mike Sanderson's team scoring the new world monohull 24 hour record of 546 miles in the latter stage of the leg. "It is one thing to do a record when the record is the only thing you have to do and you can sail whatever angle you want to sail," he says. "It is another to do a record when you are racing when you have a fixed point you must get to. That is an added complexity. But what struck me the most was the wind speed they did it in - it was never more than 28-29 knots so doing 22.75 knots average in 28 knots of wind is quite good."

And obviously the boats go even faster in 35 knot winds of the type they can expect to see in the Southern Ocean. "Speed in heavy air is very dependant upon the waves which is why I think in the Southern Ocean they will smash the records no problem - all of the boats," says Kouyoumdjian. "546 I am sure will be broken before they get to Kerguelen [mid-Indian Ocean]. Down there the waves are 23-25 knots so the boats will be sailing at 30-32 and slowing down to 23-25, rather than when they did the record they were doing 26-28 knots and slowing down to 17-18. So I think they will average 23-25 knots average or 600 miles in a day, no problem. I think 600 miles will be done before Melbourne and most certainly before Rio."

Such speeds are verging well into multihull territory - the 60ft trimaran 24 hours record currently stands at 625 miles - and this means that designs in the future should look more closely at the aerodynamic aspects of the VO70s. As has been discovered in the multihull world, when sailing at 30-40 knots drag from mast, rigging, stanchions, lifelines and even deck fittings has an increasing effect on performance and it is for this reason that most 60ft trimarans and maxi-multihulls have spread-free wingmasts. Unfortunately the present iteration of the VO70 rule doesn't allow for such innovation. Juan K says he would like to be able to use Open 60-style deck spreaders as a way of first getting weight out of the rig, but also as a place from which to trim gennikers.

While ABN AMRO Two was mercifully free from carnage on leg one, on ABN AMRO One this was less the case with a steering arm breaking, a small fire on board and crewmen Tony Mutter and Jan Dekker being washed aft with such momentum that they demolished the port steering pedastial. The reason that ABN AMRO Two finished the first leg relatively unscathed can be attributed to her being the most tried and tested boat in the fleet combined with Seb Josse applying his Open 60 shorthanded sailing techniques to how the boat is pushed.

Knowing how hard the boats should be pushed we expect will be as much a deciding factor in the Volvo Ocean Race as whether your boat has more lead in its bulb or a better sail program.

"It is very early and anything can happen," says Juan K. "But these boats cannot be designed not to break. When we talk about sailing into a new territory I think this is very true. This kind of yachting is going to a place where breakages are very much in the hands of the crew as much as the designers or engineers. If they want to break the boat they can break them and they can break them in 15 knots of wind."

That statement has been true of the large multihulls for years now and after one spate of structural disaster in the last Route du Rhum, designer Nigel Irens was advocating the mandatory fit of load cells in key highly loaded areas around the boats from which crews would be able to guage how hard they were pushing their craft, in the exact same way as Formula 1 race car drivers can tell when their engine is going to blow up by how far into the red they push the rev counter. Something of this ilk should also be considered for the Volvo Ocean Race boats.

At the present time Juan K reckons that what is needed and what he has achieved with the ABN AMRO One at least is deep interaction. "A strong point of this team, is that between our office and in particular the black boat sailors there has been a dialogue backwards and forward that allowed the end product to be a step up from what you could do without that kind of discussion. When you are going into these new territory and you are pushing the limits you need to be very close to the end users.

"I don’t think we could give Moose [Mike Sanderson] an absolute number or a scale or something, because it is very difficult to know it and it would be difficult to have a sensor in the boat to tell you that you are there," continues Juan K. "But by interacting with him and him knowing how it was designed and what philosophy and criteria were used and what every single piece of the boat is made, the whole crew can build in a self-made type of opinion as a type of progression. They are very good sailors and they know what they are doing - Moose, Crusty [Mark Christensen], Brad [Jackson]. If you are going to trust anyone to go out there with one of these machines it is them."