The Louis Vuitton Challenger Series begins in late August and runs until late October. Why so long? Well, the addition of two more teams compared to the last America’s Cup means an extra round of the Challenger Series. All six teams, including defending champions Emirates Team New Zealand, compete in the round robin before the first Challenger is eliminated. The remaining four then compete for the title in two knockout rounds.

The length and timing of the Challenger Series presents a unique element to the design challenges of this America’s Cup. It would not be too cynical to say that this was probably part of the Kiwis’ clever defensive strategy.

The Challenger Rounds take place in August and September, when Barcelona typically experiences more consistent thermal winds with predictable patterns and moderate seas. The America’s Cup Match in October then brings greater variability with a mix of weaker thermal winds but potentially stronger gradient winds and significantly worse seas.

This difference in expected conditions requires the challengers to design versatile boats capable of performing well in the more predictable temperate conditions of September, while the defender can prepare specifically for October, which is characterised by less consistent but higher average wind speeds (depending on the time of day) and much greater wave heights.

During the event we can expect the following conditions:

ETNZ’s Taihoro just needs to be optimised for October conditions. Photo: James Somerset/Emirates Team New Zealand

August/September

Dominant winds – The synoptic summer wind over Spain is generally from the northwest. In Barcelona it is almost completely blocked and deflected by the Pyrenees. Instead, the Garbí wind, a thermal breeze from the southwest, prevails in summer. It usually starts in the early afternoon at 10-15 knots and increases to 14-18 knots in the afternoon.

Sea state – 0.4–1.5 m swell from offshore.

Other winds – Southeasterly winds have difficulty reaching the coast directly, resulting in lighter breezes. Easterly winds can bring larger waves (1–2 m) when the wind is moderate, but are often weakened by thermal effects when the wind is light.

temperature – Longer daylight hours and higher temperatures can improve thermal wind patterns, making the Garbí more consistent and predictable.

The article continues below…

October

Dominant winds – The thermal influence of the Garbí decreases as temperatures drop. In general, this results in weaker southwest winds. However, the Garbinada is a stronger southwest wind driven by a gradient wind with a westerly component. This synoptic wind runs parallel to the coast and becomes southwest or south-southwest. These windier days can increase the average wind strength.

Sea state – Increased Mistral in the South of France leads to significant waves, which in Barcelona can occur as 2-3 m swells. Combined with southwest winds, this can lead to unpleasant, tricky conditions.

temperature – Lower temperatures reduce the strength of thermal winds. There is a higher probability of northerly gradient winds blowing around the Pyrenees, resulting in more days with east-southeast or even northeast breezes.

If you liked this….

Yachting World is the world’s leading magazine for ocean and offshore sailors. Each month we offer inspiring adventures and practical features to help you achieve your sailing dreams.

Expand your knowledge with a subscription delivered to your home. Check out our latest offers and save at least 30% off the list price.