French multihull circuit kicks off its 2001 season with a tactical course around the Azores Islands

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Jean-Luc Nelias' Belgacom soon after the start of the 2001 Challenge Mondial Assistance. A little bit of wind goes a long way with these Open 60 trimarans. In the end, Belgacom placed second just 12 minutes behind Alain Gautier's Foncia-Kingfisher after 2700 miles of intense and difficult sailing.

Synoptic pitfalls make for
a tactical ocean race

French trimarans kick off their Atlantic season
with a real sleeper

May 31, 2001

Who would have guessed the synoptic pitfalls embedded within the inaugural Challenge Mondial Assistance!

In fact, the only thing predictable about this ocean yacht race was the remarkably close finish after 2700 miles of hard sailing.

The challenging course was a new addition to the French formula one trimaran’s Atlantic sailing season and one which we hope is held again, and again!

The Challenge Mondial Assistance traced a 'boomerang' route from Cherbourg, in Brittany, around the Azores and through the Straits of Gibralter to Tarragona on Spain’s east coast. Those in the know were confident of a close finish - and there have been few as close, and as slow, as this one.

What no one predicted was an unusual weather pattern which made a mockery of 'standard' spring weather in the east Atlantic.

But never forget: Pigeon-hole the weather, and sooner or later you’ll get a kick in the arse.

Azores high?

Prior to the May 12 start, high pressure in the East Atlantic presented itself in an unusual pattern. It centred over the Azores - a common location, and the reason behind the name 'Azores High'. However, the synoptic package included a ridge extending well to the north-east covering parts of Scandinavia. This unusual bubble influenced the path of jet streams north and south, with storms developing east of Newfoundland steered by a northern jet up the Denmark Strait, while another jet drove low pressure into the Mediterranean.

In the final hours before the start the dominant jet stream in the North Atlantic, and the ridge of high pressure over Scandinavia, weakened. At the same time a powerful low, created east of Cape Hatteras, moved towards Europe. With no dominant jet to steer it, this low became trapped, or 'cut-off' and planted itself in the ocean east of Portugal.

For four days the low revolved, sometimes quickly, other times slow. Multiple low pressure centres evolved to 'dumbell' around the other, wreaking havoc with skippers, and their navigators, fighting for supremacy in the Challenge Mondial Assistance.

Gentle start, destructive first night

Eight trimarans started from Cherbourg in light easterly winds under the influence of high pressure over the continent, gybing constantly to maintain best wind angles. But as they sailed past Cape Finesterre and west, towards the cut-off low circling in the east Atlantic, winds veered to the south and strengthened. Gusts in squalls reached 50 knots and reports of boat damage began to filter through.

During one squall Bourgnon’s Bayer found itself without steering while surfing at 30 knots. That was hair-raising moment indeed, and it cost them and extra 25 miles to the north - downwind - and 90 degrees away from their desired course before things were sorted out.

Daggerboards and foils were popular failures, with Belgacom, Groupama, Foncia-Kingfisher reporting similar damage before reaching the Azores. Titanium forestay hooks also failed which in turn damaged mast sections on the brand-new tri Banque Populaire and Groupama.

Lalou Roucayrol’s Banque Populair - launched in April - eventually retired as a result of the damage. New boats are prone to failure, but in this case it must have posed pain for the skipper, considering Roucayrol’s disaster during last year’s Europe 1 New Man Star trans-Atlantic race, in which he capsized and later abandoned his tri to the waves off Newfoundland’s Grand Banks.

Marc Guillemot understand’s Roucayrol’s pain, after structural failure led to his crew of five being winched off La Trinitaine - Team Ethypharm by helicopter less than 48 hours after the start.

Negotiating the low

On the second night at sea the fleet split with Yvan Bourgnon’s Bayer furthest south and Franck Cammas’ Groupama well north. As Cammas and his navigator Marcel Van Triest explained by email, they were keen to sail as far north as possible before the low crossed their path. At one point they were sailing 90 degrees to their course to achieve this aim. Bourgnon, meanwhile, sailed south for exactly the same reasons as Cammas - to be in the right spot with the best winds, as the centre of the low approached.

Forty-eight hours later, with Groupama 53 miles behind, it was clear that Bourgnon and Bayer’s bid paid off. In hindsight it is easy to see why: Winds in the cloud band east of the low pressure centre were very light, while winds rotating counter-clockwise around its centre were not too strong. Sure, Bayer had headwinds, but at least Bourgnon and crew had wind!

In addition, the low was stalled - rotating in place, although it gave the impression of movement as new centres 'dumbelled' around each other. Therefore, the typical west to east momentum of ’normal’ storms was non-existent.

Alain Gautiers’ Foncia, with Vendee Globe success story Ellen MacArthur navigating, remained equally positioned between Bourgnon and Cammas. But they still felt the effects of light winds under the low. At one point Foncia and Groupama recorded just two knots VMG - velocity made good - whereas Bayer was recording 11.5 knots VMG.

Yvan Bourgnon and crew led around Sao Miguel island thanks to that routing decision off Cape Finisterre but would lighter airs on the next leg separate the old boats from the new?

Around the Azores

As the fleet rounded the Azores the complex low finally faded. The jet stream to its north settled on a path right over the islands and this pattern would remain right through to the end of the race. The result was a stream of low pressure, steered by the jet, traveling from Sao Miguel through the Straits of Gibralter. Because it was late spring, and the strength of these lows weak, the result at deck level was light and variable winds.

Outside the calm moments were bands of breeze and on the leg to Gibralter, Bayer cracked a daggerboard case after hitting something hard, resulting in 100 litres per hour flooding in.

Meanwhile, Gautier’s Foncia-Kingfisher - which had earlier damaged its starboard foil - began to feel the lack of performance in the lighter airs around Gibralter.

Wind returned on May 18-19 with the fleet accelerating to 25 knots. Groupama led by 42 miles ahead of Foncia-Kingfisher. Bayer a further 2.6 miles behind and Belgacom another 16 miles behind Bayer.

As the fleet approached Gibralter winds eased off, and Foncia-Kingfisher elected to sail south - into light airs. With 80 miles to Gibralter the four leading boats lay within 20 miles of each other.

On entering the Meditteranean, the winds eased off entirely, and Groupama saw her lead evaporate after her mainsail head broke and Cammas and crew had to anchor for three hours to carry out repairs.

‘We lost what we gained and now we must start all over again,‘ noted Groupama navigator Marcel Van Triest, three days before his boat sailed into Tarragona. ‘We must get ready for tight racing in light airs until the finish.’

Typical Med

"It is typical Mediterranean conditions," noted Alain Gautier. "We must be patient. The wind is very light and the situation is most tricky."

Belgacom’s Jean-Luc Nelias said it was useless to set up a strategy. "It is a lottery at the moment," he said with despair. As it turned out, Jean-Luc had cause to celebrate two days later.

The sleepy synoptic pattern remained all the way to Tarragona, with some boats finding a narrow corridor of wind and accelerating away, only to fall into a hole and wait while the rest of the fleet caught up. Even Thierry Duprey’s Gitana IX, built in 1988 and the oldest boat in the fleet, got to within 139 miles of the leader.

What made this race so interesting is that Bourgnon’s Bayer and Nelias' Belgacom, are also old boats - launched within two months of each other in 1990. While they have been heroically maintained, and modified over the years, they remain heavier than the newer boats and struggle in lights airs. Yet they gave the newer, more technologically advanced tris a real run for their money.

Bayer led the pack off and on throughout the race, and held the lead for much of the Mediterranean up until the last day, eventually finishing fourth. Meanwhile Belgacom - Loick Peyron’s old Fujichrome - relented her lead only at the very end, finishing just 12 minutes behind Gautier’s Foncia-Kingfisher. The win for Gautier and navigator Ellen MacArthur will further enshrine the talent of this remarkable young woman.

Franck Cammas’ Groupama - brand new only last year - finished third.

Despite the light airs, and slow speeds, the Challenge Mondial Assistance provided great sport for those who enjoy synoptic tactics, and what better way to illustrate the ways of weather than with the world’s fastest trimarans. More of it, we say!

A look at the weather

East Atlantic infra-red satellite images
animated (228kb)
May 12, 00gmt to May 15, 0600gmt

Image © UK Bureau of Meteorology

This animation clearly shows the mess the fleet of Open 60 trimarans dealt with during the first 78 hours of the race. The animation begins at midnight, GMT, 12 hours before the race stared from Cherbourg. Note the cloud-less sky over Brittany and the English Channel indicating high pressure and light winds.

The first front hits the fleet during their first night at sea and damage is widespread - broken daggerboards, foils, and forestay 'hooks' are common failures.

East Atlantic pressure
May 14, 00gmt

Midnight, on the second night at sea: The first cold front has crossed the French coast, while west of Cape Finisterre, the fleet negotiates alternating bands of light and windy weather underneath cloud bands generated by this complex low. Note the two low pressure centres. Picking where the wind is blowing best for a course headed to the Azores requires some serious thinking.

You can see in the animation above that the northern of the two low pressure centres becomes dominant and slides to the south-east. Those caught underneath the low pressure centre find little wind but confused and rough seas. Not ideal for a racing a trimaran.

Satellite radar-derived surface winds (quickscat)
May 14, 10.05gmt

Image © NOAA

At this point, the low has coalesced into one dominant centre before it slides to the south east and fades altogether. The coloured arrows show wind direction (to within 20 degrees) and velocity. Winds due south of the low's centre are just five to ten knots (light blue to dark blue in colour), and yet seas left over from days of abrupt wind changes would have to be uncomfortable indeed! There is no way a trimaran in this corner of the ocean would be able to sail quickly without jolting the wind out of its sails.

Note the green arrow a little further south - this indicates winds 15-20 knots. This extra wind would have benefited Bourgnon's Bayer, which positioned itself furthest south as the fleet fanned out west of Cape Finisterre. The down side of this stronger wind band is that it contains gusts well into the 30 knots range (red arrows). Plenty of wet sail changes were the order of the day (and night) on this leg of the race!

Atlantic jet streams
May 18, 00gmt

By this time the fleet has rounded the Azores and is heading for Gibralter. Note the jet stream undulating over the East Atlantic and right into the Mediterranean! This steering path will remain until the end of the race on May 23, bringing one low pressure cell after another directly over the race fleet. As it is late spring, these lows are weak and fail to pack much of a punch. The result? Light and variable breezes all the way to Tarragona, and a record slow race for the Open 60 trimaran fleet!

East Atlantic pressure
May 18, 00gmt

This composite cloud and pressure map shows high pressure north of Spain and a band of low pressure running from the East Atlantic into the Mediterranean. This synoptic situation is more typical of late spring in Europe, although the light airs in the Med did bring more than their usual amount of despair to the skippers and their navigators as they tried, often in vain, to predict where the next wind trend might come from.

Hot links for the east Atlantic:

The UK's met office offers terrific weather images and information, starting with this animated satellite image of the eastern Atlantic and Europe, updated every six hours.

Check out winds in more detail with isobars included, in this cloud and pressure composite image.

For an animated look at how winds behave, complete with colour-coded isobars, view this three-day animated pressure forecast.

View the east Atlantic in infra-red from the UK's met office.

Surface pressure for the eastern North Atlantic compliments of Ocean Weather.

Quickscat satellite derived winds for the east Atlantic:
Waters west of Great Britain including the English Channel and Bay of Biscay,
Waters from the Azores to Gibralter,
Waters of the northern Med and southern Med (detail here is poor).

24 hour forecast for Wind and direction in both the north and south Atlantic, thanks to the ocean modelling branch of NOAA. (forecasts use the AVN model). Also: 48 hour forecast, 72 hour forecast, 96 hour forecast.

Wind analysis from the University of Wisconsin showing surface, upper and jet stream - or water vapor - winds. As well, there are charts showing wind shear and upper level divergence. For the arm-chair sailor, the low-mid level infra-red winds tell an awful lot about the sea state where the boats are. Colour-coded arrows report wind strengths and direction at different levels. Remember: Friction at the surface slows the wind down a bit, so it will never be as strong at wave height as it shows on the 900hPa chart.

The University of Nottingham offers geo-stationary satellite information showing the east Atlantic and Europe/Africa.

The Aviation Weather Centre offers these terrific flight level charts SIGWX) which show the position of jet streams over much of the globe (mostly Northern Hemisphere). Because upper level winds, like the jet stream, steer our weather systems, knowing where these winds are and how they are behaving helps us to understand whether systems are moving east to west quickly or whether they will stalling because of a kink in the pipe-line.