Mark Chisnell – Leg 9 Preview – Intense OpeningBlog
First up, congratulations to Abu Dhabi Ocean Racing for all but confirming the overall victory on Leg 8 to Lorient. And to Team SCA for a fine Leg win – not to mention confounding my prediction that their offshore option from Cape Finisterre would see them reeled in. And finally to Team Vestas Wind for a great comeback that has hopefully made worthwhile the monumental effort undertaken to achieve it.
The final leg of the 2014-15 Volvo Ocean Race is as different as a mountain stage of the Tour de France is to the final time trial. Once again, we can forget the climate zones, the trade winds and sub-tropical highs, the doldrums and storm tracks. The 960 miles from Lorient, France to Goteborg, in Sweden, are going to be all about the weather.
Well, that and the heat of the sun driving local sea and land breezes, and, of course, let’s not forget the tidal flow. I’m sure all the navigators will have been digging out the tide tables for the English Channel and the North Sea, because they are going to need them.
Let’s start with the weather once again, in Pic 1 (once again courtesy of the marvellous www.magicseaweed.com) we can see the forecast for start time tomorrow at 3pm. A zone of high pressure is running north-east to south-west from the south west tip of England, down the coast of France and Spain. The high has a gentle clockwise circulation around it, and this is providing a light and very variable breeze in the English Channel.
There is some northerly breeze shown for the first section out of Lorient and up to Ushant on the north-west tip of France. This could be reinforced or modified by a local sea breeze – we’ll have to wait and see on this one as I’m not familiar with that bit of coast line. But hopefully, the start should get underway with at least 10 knots of wind.
The fleet will likely beat upwind to the corner, then as they turn east into the Channel the wind will disappear. We should be well on the way to nightfall by then, so any local sea breeze will almost certainly have evaporated too. From here to the Dover Straits there really isn’t much wind at this point, and it will be all about playing local thermal winds, and dodging the tides.
A Word About the Tides
The tidal streams in the English Channel are strong, commonly reaching 3-4 knots with a lot more where it compresses on headlands. The tide flows in from the west to the east for six hours, then back out again from east to west. So they have roughly six hours of favourable current – time best spent out in the main channels in deep water – and then six hours to dodge it inshore and in shallow water.
This more or less holds true through the Dover Strait and into the North Sea, except that the tide flows into the North Sea from the north, and so it ebbs from the south to the north. The two inbound flooding tides meet in the North Sea, and that will create some added complexity when they get that far and have to deal with it. A good tidal chart should reveal all however…
Back to the Weather
The high pressure and light winds will hold sway in the English Channel until Wednesday morning, when a fresh south-westerly wind will fill in from the English coast, filling from the north to the south. In Pic 2 we can see the situation at 3pm on Wednesday, 24 hours after the start. The westerly is in and it’s filled just about all the way to Ushant, driven by a big low pressure system centred up over Greenland.
By this time the race will have switched from a tricky tactical light air race, to a downwind blast-off. The transition between the two could well decide the race in this first 24 hours.
Seriously Tough Nut
It looks like the forecast will create a difficult strategic problem for the teams. They will almost certainly want to hug the French shoreline on the Tuesday night, because it will provide both potential relief from the tide, and the possibility of a night breeze – a drainage wind that flows off the cooling land onto the water. But with the new wind coming from the north, at some point they will have to make a break offshore to try to reach it first.
The timing will be everything – a boat that goes too early, particularly if they make the move into adverse tide, could find themselves going backwards. A boat that goes too late could find themselves still struggling in light winds, while others scoot off up the Channel with a solid breeze under their skirts. This could easily be the race winning move. It could be a race winning move because once that wind fills in it will provide a 20+kt westerly that should drive them at pace all the way (or very close) to The Hague.
It depends a lot on how much progress the fleet make on the first night, but just in case they haven’t got to The Hague yet, let’s have a look at Pic 3, with the weather for Thursday at 3pm, on the 18th June. The low has stalled and filled, and with the high moving northwards in its wake, it’s set up a strong (35+kts) north-westerly across the North Sea.
So whatever happens, it looks like once they negotiate the light air in the English Channel on Tuesday night / Wednesday morning, they will have strong breeze at fast downwind angles all the way to The Hague.
Ok, there’s still the traffic to manage in the Dover Strait, and anyone who has had the pleasure of sailing on the North Sea will know that it’s shallow and kicks up a pretty ugly and potentially boat-breaking wave pattern… but I wouldn’t be surprised to see the positions on Wednesday afternoon lock-in all the way to The Hague.
The rules for the pit stop are that the first boat to arrive will restart at midday on the 20th June. The rest of the fleet will follow at the same intervals at which they arrived after the leader. So let’s have a look at the chart for midday on the 20th, in Pic 4.
A new low pressure has moved in to dominate the action, and it will be centred just north of Scotland. It will maintain a decent 15+ knots of westerly blowing onto most of the coast of Holland and Germany, and that should set the fleet up for a fast exit from The Hague, headed north-east for Scandinavia.
Once again, it’s looking like a fast reach home. Could it be that the first 24 hours of this leg will actually settle things all the way to the finish in Gothenburg? We are getting a long way ahead for speculation at this point, but let’s have a quick final look at Pic 5, which is for the 21st at midday. The low has moved east quite quickly, and is maintaining the westerly all the way along the coast of Germany and Denmark – this breeze should get them almost all the way home.
If it doesn’t… the wind dies horribly as that low continues its journey east, and it could set up a light air finish. The final miles around the tip of Denmark and across the Kattegat to Gothenburg are a completely separate geographic area to the North Sea, and they will have their own weather. There’s a high potential for change and upset in the home straight. It’s provided some desperately close finishes in the past, and it might well do it again.
All Over Bar the Shouting
Only a retirement and a couple of penalty points can prevent Abu Dhabi Ocean Racing being crowned champions – but the minor podium places are wide open. If the forecast (and my analysis) are correct it’s going to be a particularly intense and stressful first 24 hours, as the teams struggle to establish a lead that they ought to be able to hold all the way to the finish in Gothenburg.
I’ll see you back here next Monday, by which time we will know how it all went down – and who owns the podium for this edition of the Volvo Ocean Race.