Volvo Ocean Race - Timing critical?
by Volvo Ocean Race on 20 Feb 2012
For the Volvo Ocean Race fleet, perfect timing may prove critical over the first few days of the second stage of Leg 4, which will take them on a 5,220 mile journey into the unknown on their way to Auckland, New Zealand.
The fleet of Volvo Open 70’s, at the start of leg 4 of the Volvo Ocean Race 2011-12, from Sanya, China to Auckland, New Zealand. Paul Todd/Volvo Ocean Race© http://www.volvooceanrace.com
As soon as the fleet leaves Sanya the boats will face their first challenge in the South China Sea on tricky 700 nm stretch to the Strait of Luzon.
According to race meteorologist Gonzalo Infante this opening section could be key and if the teams time it right they could get a major boost from favourable winds after the strait.
Infante is predicting that the extreme conditions of the last 24-hours, caused by the presence of a high pressure system to the north and a low pressure system to the south will begin to lessen as the low dissipates over the next day or so.
However, this could leave behind a difficult sea state making it imperative that the fleet make it through the Strait of Luzon as quickly as possible to hook into stronger steadier breezes from a newly developing low pressure system to the north east.
To further complicate matters, as the southerly low pressure system breaks up the winds will shift progressively to the east making a northerly passage through the strait close to the island of Luzon the favoured option.
Infante says after the strait the crews will be looking for any opportunity to get to the east to set themselves up on the optimum angle for fast sailing in the north easterly trade winds later on.
'East is best,' Infante said. 'A well timed exit from the strait will enable the boats to take advantage of strong winds from the easterly moving low pressure system. If they get it right it will be like taking an eastbound train to line up perfectly for the north east trade winds.
'If they miss the train then they will be forced immediately south closer to the island land masses of the Philippines, Papua New Guinea and Indonesia where the trades are less stable and harder to predict.'
After crossing the Doldrums for the third time in the race so far, the teams must negotiate the South Pacific Convergence Zone (SPCZ) -- a permanent weather front stretching southeast like an extension of the Doldrums.
'Even if the crews find a quick route through the Doldrums their passage could be stalled in the SPCZ,' Infante said. '2012 is a La Niña year, (an ocean atmospheric phenomenon in which sea temperatures are lower than normal, lessening the impact of the SPCZ), but it is still a consideration for the teams.'
Once past Fiji, the route takes the teams past the east coast of Australia during the peak of the hurricane season.
'The risk of hurricanes will not directly threaten the teams, who will be able to see them well in advance and plan a safe route accordingly, but they will have a massive impact on strategy, potentially forcing the teams to adopt a course far from the direct path,' Infante said.
The final stage of the leg is though the Tasman Sea, an area of dynamic weather that can change quickly.
Infant added: 'There won’t be many radical choices tactically here but the constantly changing weather could provide one last hurdle before reaching Auckland.'
Summing up the leg Infante said: 'It is going to be very tricky with many unknowns due to the dynamic nature of this section of the world’s oceans.
'From the tropics to the Tasman, the weather systems are fast moving and variable. It’s going to be one of the most tactical legs of the race so far with plenty of opportunities to reward bold tactical manoeuvres.'
A quick run could see the first boats arriving in Auckland within 15 days, however it could take up to 23 days to complete the leg.
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