Into the third week of Leg 2 of the Volvo Ocean Race, and the fleet are grappling with the final big strategic problem of this leg – the South Atlantic High. After several days of drag racing, the pressure has been on the navigators since the back end of last week, and it’s not over yet. They have finally got some breeze and are headed for Cape Town, but it won’t last... and now Team Brunel have played their Stealth card and everyone must be wondering if they are headed for the deep south, or is it a fake?
South Atlantic What?
If “South Atlantic what?” was your reaction to the first paragraph, then you need to get up to speed with the idea of climate zones in general, and the strategic challenges of Leg 2 in particular, so please stop by the leg preview.
If you don’t have time to click through, the main takeaway point for these strategic reviews is that the earth’s oceanic climate features distinct bands, lying horizontally and looping the globe, running out from the Equator to the Poles in a mirror image. It’s the transitions from one climate band to another where the race is often won and lost, these are the places where conditions can radically change and gains and losses can be big.
A week ago when we concluded the previous strategic review, the fleet had just exited the Doldrums and were sailing south in the trade winds. They were in a tight pack with very little leverage (perpendicular distance to the course) – as we can see in Image 1, from 13:00UTC on the 13th November.
Image 1 - Geovoile
At that moment there was an opportunity to do something radically different, by going around the South Atlantic High to the north – this is the red route in Image 2, showing the possible routes for the fleet from their position a week ago. But, as predicted, no one stuck the house on that spin of the roulette wheel, and within 24 hours the whole fleet were committed to the ‘traditional’ route seen on Image 2 in blue. So it’s probably time to have a look at the strategy for this in a bit more detail.
Image 2 - Jessica Sweeney / Expedition
The traditional route doesn’t go direct to the destination, Cape Town, and the reason is the next climate zone to the south after the trade winds. This is an area of semi-stationary high pressure that in the South Atlantic is called the South Atlantic or St Helena High.
In ‘normal’ circumstances, this area of high pressure stretches across most of the South Atlantic. In Image 2, it’s visible as the white / light blue area of very light winds with two centres west of Cape Town – remember that the wind flows anti-clockwise around a high in the southern hemisphere (it goes the other way in the northern hemisphere).
It’s this hole in the wind that dominates the strategy from the moment the fleet exit the Doldrums all the way to Cape Town. The traditional route shown by the blue line in Image 2 is to head south down the coast of Brazil, skirting the edge of the high and staying in the south-easterly to easterly and then north-easterly flow down the left-hand edge of the high’s centre.
Eventually, the boats get far enough south that they will get into the next climate zone, the Westerly Storm Track, and be within reach of a low pressure system moving from west to east as it circulates the Antarctic. The boats will pick up the new fresh breeze from the low and – if they get the breaks and do it right – they can ride that wind all the way to Cape Town.
This was the strategy everyone bought into at the beginning of last week, and since – for the first few days – it called on them to head south, that’s exactly what they all did. It was 14:00UTC on the 16th November before anyone made any moves at all. We can see in Image 3 that team AkzoNobel (purple) has moved out to the east of the leading pack of Dongfeng Race Team (red), MAPFRE (white), Team Brunel (yellow) and Vestas 11th Hour Racing (orange).
Image 3 - Geovoile
You might have noticed that the leaderboard doesn’t agree with me that this is the leading pack, putting Vestas 11th Hour Racing in last place. The website has explained this with each position report but just in case you missed it... The reason is that they are scored on their distance from Cape Town – but as we know the fleet can’t sail directly to Cape Town. The leaderboard doesn’t account for the necessary detour, and so it doesn’t accurately represent good strategic position at this point in the race.
East or west?
Let’s look at the bigger picture as team AkzoNobel’s early move to the east plays out. In Image 4 from 13:00UTC on the 17th November, 24 hours later, we can see that team AkzoNobel have stuck with their plan, and are now being tracked by Turn the Tide on Plastic (light blue), and Team Sun Hung Kai / Scallywag (grey) – all three out to the east.
Image 4 - Geovoile
At the front of the fleet (I’m resolutely ignoring the leaderboard), Dongfeng Race Team and MAPFRE have slowly adjusted their course so that they are now sailing south-east. Behind them Vestas 11th Hour Racing and Team Brunel have gybed a couple of times to position further west than the rest of the fleet – a clear difference of opinion from those all the way east. So finally, we have some leverage and it’s game on.
The reason for the course changes and gybes was that as they sailed south they were moving relative to the centre of the high pressure, and going from a north-easterly breeze to a northerly wind. On port gybe, the slowly shifting wind slowly forces them straight into the centre of the high pressure, where you can wind up windless and very slow. Meanwhile, those that hold or gybe to the south and west sail a lot further, but sail in much better wind at faster speeds and come out in front.
Speed v distance
It’s the same old dilemma that we’ve seen several times already in this leg of speed v distance. However, this is one time when I’d always back sailing the extra miles to get into the breeze first –– ever since Paul Cayard and Mark Rudiger committed EF Language to the south early and hard way back in the 1997-98 race and came away with a lead that won them the leg, and – you could argue – the race.
It reminds me of the story of Icarus, the son of master craftsman Daedalus who built wings of wax and feathers so he and Icarus could escape from the Island of Crete. Icarus ignored his father’s advice and flew too close to the sun – his wings melted and he fell into the sea and drowned, a victim of his own hubris. If we swap the centre of the high for the sun, then anyone that flies too close believing they can shortcut the route to Cape Town can often come crashing back down to earth... And so it turned out.
Too close to the sun
If we look at Image 5 from 18:00UTC on the 18th November we can see that everyone has now gybed and is headed south-west on port. MAPFRE leads the charge to the south-west, and is now 200 miles directly in front of Team Sun Hung Kai. It’s the latter that (along with Turn the Tide on Plastic) has been badly caught as the high has moved west and enveloped them in light air – check out all those gybes as they wriggle and try to escape.
Image 5 - Geovoile
Team AkzoNobel barely cashed out of their easterly position in time, and are hanging onto the coat-tails of the leading group by their fingernails. The big surprise in this picture is Dongfeng Race Team who have held onto port gybe for way too long. They are now trailing MAPFRE in the race to the south-west – a boat they were beside just 30 hours earlier – by a hundred miles.
If you’re wondering why I sound so confident that the race is being won by boats sailing in almost the opposite direction to the finish line (Cape Town is actually due east of them at this point), then look at the wind speeds. The boats further south and west have much better windspeed. MAPFRE at 18.8 knots has almost double the wind of Turn the Tide on Plastic. More power from the wind means more speed, and from these positions they should be able to zip round the outside.
It’s never as simple as that though, and even while MAPFRE was charging south-west, they still had to pick the right moment to gybe back to the east and convert their position into an actual lead, by putting themselves between the rest of the fleet and Cape Town. This was a lot harder to do than ‘normal’ because the overall pattern in the South Atlantic remains much more complex than the climate model.
If we look at Image 6 from 02:00UTC on the morning of the 19th November, we can see the moments just after ‘the gybe’ with everyone now heading east. They are all in good breeze, with the fleet lined up south to north with MAPFRE maintaining lots of leverage – they are about 80 miles south of the group of Team Brunel, Vestas 11th Hour Racing and Dongfeng Race Team. Next comes team AkzoNobel, then way up north Turn the Tide on Plastic and Team Sun Hung Kai / Scallywag.
Image 6 - Geovoile
Westerly Storm Track
Behind the fleet we can see plenty of northerly breeze and deep in the bottom left hand corner of the image, the demarcation line of a powerful front, spinning off a low pressure system. This is all as it should be, and when that low moves east on the Westerly Storm Track, it will pick up the fleet and hurl it at Cape Town.
They do need that low to start moving east though, as right in front of the fleet the situation is very messy, with the high split into two centres, one to the north of the route to Cape Town, and one to the south. The road to the finish line goes right through the middle of that spectacularly unsettled weather. They don’t want to have to deal with it, they need the low to push it out of the way and clear the path to Cape Town... if only.
Stalked by the high
If we bring it up to date and look at the most recent position report in Image 7 from 13:00UTC on the 20th November (today) we can see that the lead pack has converged onto MAPFRE’s line. It’s given the Spanish boat a ‘real’ lead of just over 30 miles from Vestas 11th Hour Racing, with Dongfeng recovering to third place another 12 miles behind. On many occasions, that would be it for this leg – the fleet would rock and roll to Cape Town with lots of great video and Southern Ocean action. Not this time around.
We can see in Image 7 that the overall weather situation is still pretty messy (that’s the technical phrase). The fleet is riding the edge of a front from a big low pressure system centred to their south-west –– but the ride won’t last. And the big, three... no, the four headed monster of the South Atlantic High will stalk them all the way to Cape Town.
Image 7 - Geovoile
The website has added a ‘Predicted Route’ button to the tracker – fourth icon from the top on the left-hand side – so we can look at what’s coming without ‘leaving home’ this week. The Predicted Route uses the weather forecast and a table of the boat’s performance in different wind speeds and at different wind angles to calculate the optimum route to the finish.
In Image 8, I’ve used the Predicted Route (dotted) to move forward 24 hours to 13:00UTC tomorrow, 21st November and it’s already getting pretty ugly.
Image 8 - Geovoile
The fleet is still riding the front, but they are hanging onto an increasingly narrow band of decent breeze. The high is expanding eastwards from behind them, and although the other two areas of high pressure that were in front of them have slid north, they are a long way from out of the game...
Let’s go forward another 24 hours to 13:00UTC on the 22nd November in Image 9, and we can see that while most of the fleet are still threading the needle in an increasingly narrow area of wind between two high pressure centres, the northern boats look very vulnerable (I don’t think the Predicted Route is working for Team Sun Hung Kai).
Image 9 - Geovoile
All access passes revoked
Now look at Image 10, another 24 hours into the future, at 13:00UTC on the 23rd November and it’s properly desperate for everyone. The front has finally faded and the entire fleet is now struggling its way through a massive and confused area of high pressure with ridges and centres spread over 1500 miles, blocking all access to the finish.
Image 10 - Geovoile
This will be like riding into a brick wall and the only escape will be getting far enough east to break through onto the other side and into the fresh south-westerly breeze blowing up to Cape Town from the Cape of Good Hope – an outcome visible in Image 11 from 22:00UTC on the 24th November.
Image 11 - Geovoile
The predicted route thinks the lead boats can get through this high pressure blocker in reasonable shape, but it’s very hard to predict. The high doesn’t need to get much stronger much quicker for them all to get trapped for a significant period. And the bottom line is that no one is going to ride this first front all the way to Cape Town. And that means there is an opportunity for the boats trailing behind.
This gives us a clue why Team Brunel has gone into Stealth Mode. The boats get fleet position reports four times a day, at 0100, 0700, 1300 and 1900 (all times UTC), and once each leg they can go into ‘Stealth Mode’ withholding their position from everyone for 24 hours. It means that a team can make a big tactical move and no one will know until it’s too late to follow. In this case, the big move is to gybe south.
The fleet is currently sailing in a north-westerly breeze, but if the front moves ahead of them they will start to see the wind shift (or ‘back’) round to the west – and this will create an opportunity to gybe and sail south on starboard to meet the next low pressure system coming in from the west. This system is forecast to be a lot stronger, and it’s forecast to go all the way to the finish line, clearing the high pressure blocker out of the way.
Taking the next train
The strategy, or perhaps I should say the hope is that those boats that keep going east won’t be able to cross the high pressure blocker before the next low pressure arrives. And that anyone riding the second low will have a passing lane into the finish, that will allow them to go around those trapped by the high. Effectively, they are getting off one train that’s headed for a siding, to get on a second that goes right to the destination.
It’s a high risk move – everything depends on how long the current front lasts, how badly the fleet get trapped by the high when it fades, and how and where the second low pressure moves.
So maybe Team Brunel aren’t going to make a move at all, maybe they just went into Stealth Mode to see if they could fake someone else into gybing south... but I think Team Brunel might go for it – right now, if you calculate the outcome on the southern route for someone starting 40 miles behind MAPFRE, they only finish four hours behind. It wouldn’t take much for the leader to lose another four hours trapped in the high....