From a meteorological viewpoint, the course that will lead the Transat Jacques Vabre fleet from the North Atlantic to the South Atlantic is both rich and varied, as the skipper of the MOD Edmond de Rothschild, Sébastien Josse, explains.
The English Channel
“Our first few hours of racing and the first 200 miles of this Jacques Vabre will be pretty stressful. Not only because it’s the start and we have yet to get our sea legs, but also because it’s rarely much fun making your way out of the English Channel. At this time of year, where the trains of depressions sweep across the Atlantic and surge into the English Channel, it’s very likely we will have to deal with westerly winds (with a south-west to north-west variation). If this is the case, we will have to tack amidst the numerous cargo ships and other commercial boats circulating in the area, the whole journey coloured by seas, which are rarely gentle. Lastly, this zone comprises two TSS (Traffic Separation Schemes), off Cherbourg and then Ushant, areas where we have to respect the strict navigation rules. The English Channel is essentially a small funnel, which we will need to extract ourselves from as best we can.”
The Bay of Biscay
“After the passage around the headland of Brittany, we’ll gradually distance ourselves from the shipping lanes and the traffic and enter the Bay of Biscay. It’s in this 370-mile section that we could potentially encounter the roughest weather conditions of the race. Indeed the northern section of the Bay of Biscay is characterised by the continental shelf (underwater extension of the coastal plain), which picks up very heavy seas. In this section and according to the weather system dished out to us, two options can take shape from the headland of Brittany: either we can dive down to skim past Cape Finisterre (at the north-west tip of the Iberian peninsula), or round to the north of the depressions rolling in from the Atlantic. The position of the Azores High will determine our choices, as that is what will define the weather we have in Europe. The first multihulls are likely to reach the latitude of Cape Finisterre in less than two days.”
From Cape Finisterre to Madeira
“450 miles separate Cape Finisterre from the Portuguese archipelago. This section of the course is a transition zone along the edge of the Azores High. It’s here that you see the beginnings of the tradewinds because at this time of year, we stand a chance of latching onto some downwind conditions along the shores of the Iberian Peninsula, even though the formation of small stormy disturbances, particularly offshore of Gibraltar, can’t be ruled out. It’s also an important strategic passage, as we have to position ourselves with a view to getting around the zone of high pressure. The first boat which manages to slip along to the South of the zone of high pressure, will hook onto the north-easterly tradewinds, at which point it will be able to head downwind into a more constant and more stable wind.”
Downwind in the trades of the northern hemisphere
“Once Madeira has been negotiated, we should then finally latch onto the tradewinds of the northern hemisphere; with some relatively stable and powerful north-easterly winds, kicking out an average of 20 to 25 knots of breeze, which will enable us to begin the downwind glide. That will herald the start of a drag race and a piloting battle. Despite the temperatures, which will really soar, and the speeds bordering on 30 knots, this section will be far from restful if the tradewinds are in action. It may even be a stressful period, which will call for a great deal of vigilance and lucidity on the part of the crew, because it’s downwind in a lively breeze, where you stand the most risk of burying the bows and capsizing. This is particularly true as squalls, synonymous with violent surges, can barge into the tradewinds.”
The passage through the doldrums
“The tradewinds die out at around 8° north, when we enter what we sailors call the doldrums. This zone is marked by powerful storm activity with large cumulonimbus that dump heavy rains on you. The wind here is particularly shifty and can very quickly go from 5 to 25 knots in the squalls, which are numerous in the area. However no two passages through the doldrums are the same... That’s the principal! Schematically, the doldrums form a wider cone-shape level with Africa and there is less activity on the Brazilian side. However, analysis of the zone is more complicated and the situation more illogical. Indeed, even though we always strive to traverse it as quickly as possible, the exit is considerably more advantageous to the East, where the tradewinds of the southern hemisphere await. These south-easterly winds will be our allies for the next stage of the course.”
Attacking the southern hemisphere
“Once we’re out of the doldrums, we’ll tackle a long upwind section spanning some 1,800 miles in the tradewinds of the southern hemisphere, following the curve of the Saint Helena High. These south-easterly winds should accompany us as far as the latitude of Cabo Frio, situated a few miles to the East of Rio de Janeiro. On a reach (with the wind on the beam), then downwind, we’ll launch into another drag race, mirroring our course through the tradewinds in the northern hemisphere. As a general rule though, the southerly tradewinds have less puff than their northern compatriots.”
Final home straight to Itajaí
“According to the weather patterns, the last 400 miles separating us from the finish could well spice up the end of the race. If the tradewinds stay with us all the way to the finish, there aren’t likely to be any upsets. However, if the latter run out of puff, we’ll have to negotiate a shifty transition zone. At that point we will be close to 23° South, which is where some small depressions, which roll across the fortieth and fiftieth parallel, are created. As such, we could witness an action- packed finish scenario, especially if the fleet is able to remain bunched.