Groupama in the Volvo Ocean Race: Echoes of the ridge of high pressure

Groupama Sailing Team during leg 1 of the Volvo Ocean Race 2011-12, from Alicante, Spain to Cape Town, South Africa.

Still alone offshore of Agadir, Groupama 4 is benefiting from a gentle downwind breeze of barely ten knots trickling down from the North. However, the situation is set to improve the further down the coast of Morocco they get, becoming more favourable once they reach the Canaries, at around noon on Thursday if all goes to plan. To the North of Madeira, their three rivals , Telefonica, Puma and Camper, are sailing at quite a lick but they're at 60° to the direct route towards the equator...

On the one side then, you have a French yacht, heading down the Moroccan coast all alone. On the other, you have three VOR-70s sailing in contact with each other to the North of Madeira. The upshot of this is a lateral separation stretching some 350 miles! A veritable gulf has opened up between them then after just four days at sea and 750 miles on the clock since setting out from Alicante last Saturday... Most significantly of all though, conditions are radically different, as the one boat is sailing in light downwind airs whilst the group are contending with steadier headwinds. So what's happened?

On exiting the Strait of Gibraltar, a ridge of high pressure has filled in the `void' left between the depression which shook the VOR-70s up in the Alboran Sea, and a vast disturbed zone which is stagnating off Ireland and is set to be reactivated by a secondary depression to the North of the Azores. As such a long yet narrow band of high pressure is making the transition between these two weather systems, stretching virtually right the way across from Sicily to the area surrounding the West Indies! Franck Cammas and his men decided very early on to slip along the Moroccan coast and crawl down the length of the southern edge of this ridge of high pressure, whilst the other three competitors opted to link onto the fronts associated with the Atlantic low by trucking down the northern edge of this band of high pressure. Between the two, in the area to the North of the Canaries, calm reigns.

Though it's unusual in an event like the Volvo Ocean Race to break away from the bulk of the fleet (especially from the second day out!), Franck Cammas and his crew are certainly stamping their cultural differences on the racetrack. Indeed, on a round the world, and particularly so on this Atlantic stage which the French are very familiar with (Transat Jacques Vabre, Jules Verne Trophy...), tactics are always secondary to strategy! In this way, though Groupama 4 is set to slip below the Canaries tomorrow, Thursday, she will latch onto a north-easterly tradewind system which will gradually build to over fifteen knots... Meantime, between Madeira and the Canaries, the three VOR-70s will have to make the switch from a depressionary system with W'ly wind, to a tradewind system. Between these two systems, they'll have to traverse this ridge of high pressure where the breeze will wilt away until Saturday...

However, this certainly doesn't mean that Groupama 4 will have a clear run. In reality, this Wednesday afternoon and tonight, they will have to deal with a rather messy northerly breeze of around ten knots, forcing them to hug the Moroccan coast so as not to get ensnared in the zones of calm. As such, Franck Cammas has been picking his way southwards making about ten knots of boat speed, on track for the bay of Agadir, whilst his rivals have been flying along at nearly fifteen knots to the North of Madeira. Their trajectory would have us believe that they're on a mission to pass way offshore of the Canaries archipelago so as to try to catch up with the northerly air flow as early as possible this weekend... As a result the next 24 hours are crucial and will certainly determine which of these two groups will be first to reach the Tropic of Cancer, at 23°26 North, which marks the midway point between the Canaries and Cape Verde islands.