Leg 2 Strategic Review Part 2


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Leg 2 of the Volvo Ocean Race begins its second week with the whole fleet clear of the Doldrums, the first major strategic hurdle of the leg. Dongfeng Race Team have done a great job of this opening week, and now lead the fleet south into a few days of relatively straightforward trade wind sailing.

A massive gamble?

Well, straightforward except for a shot at a massive strategic gamble that appears to be opening up in the South Atlantic. A region that currently has more in common with the churning rapids downstream of the Niagara Falls than any meaningful climate model.

Climate zones

But… I’m getting ahead of myself – first up, if you’re not familiar with the idea of climate zones in general, and the strategic challenges of Leg 2 in particular, 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.

We’ve just been through the first of these transitions, through the Doldrums, (or intertropical convergence zone (ITCZ)), a region of low pressure that envelopes the earth’s oceans roughly at the equator. It’s famous for thunderstorms, light winds, rain and sudden unexpected gusts – and that unpredictability can be very challenging.

Either side of the Doldrums are the trade winds, moderate to strong winds that blow consistently towards the equator from the north-east in the northern hemisphere, and the south-east in the southern hemisphere. Trade wind sailing is usually predictable, fast sailing. So the plan is to use the north-east trade winds to set-up for a fast transition of the Doldrums, to get back out into the south-easterly trade winds on the other side.

When we ended our last strategic review, the fleet were headed west as we can see in Image 1 (below) from 0900UTC on the 7th November. The fleet were setting up for a gybe to the south, racing west in the north-east trade winds, trying to line up a good spot to hit and cross the Doldrums – usually, it pays to be the boat furthest west, and our analysis indicated that this time around would be no different. Let’s start by seeing how that played out.

Image 1 – © Geovoile

Setting up for the Doldrums

Take a look at Image 2 from 01:30UTC on the morning of the 8th November. Everyone has now gybed and had their first go at picking a lane south to the Doldrums.

Image 2 – ©Geovoile

Vestas 11th Hour Racing (orange) are leading a tight pack in the middle, trailed by MAPFRE (white) with a nine mile deficit, then Dongfeng Race Team (red) another mile behind, and Team AkzoNobel (purple) six more miles back. Trailing this pack by about 24 miles, but on more or less the same course south was Team Brunel (yellow). The outliers were Turn the Tide on Plastic (blue) to the east (in second place, but flattered by their easterly position), and Team Sun Hung Kai (grey) to the west (60nm behind Team Brunel, but in what should have been a better strategic position to the west).

All right, let’s roll the clock forward, remembering the strategic issues from the previous review: lining up a good path through the Doldrums, while dodging a high pressure zone drifting west across the fleet’s route from the coast of west Africa.

Hitting the high

By 10:24 on the same day, 8th November, in Image 3 we can see this messy area of light air starting to affect the fleet, as the leaders hit the ‘green’ area that indicates the start of the light wind region, extending west from the coast. MAPFRE and Dongfeng have closed down Vestas 11th Hour Racing and these three now lead the pack with just three miles between them.

Image 3 – ©Geovoile

Meanwhile, the two outliers have largely folded their hands, giving up their leverage to follow the pack down the line of longitude that they have chosen – roughly 27W. Turn the Tide on Plastic has gybed west for a while, and Team Sun Hung Kai has slowly converged on the main pack’s line.

The light air could be avoided by either going south as fast as possible to try to beat it, or by going west to stay ahead of it. At any given moment, the decision between west and south was determined by the wind they had, and the clouds they could see on the radar which told them the wind they might get next; but with each manoeuvre costing time and distance it was never a clear cut decision about whether to stick (on the course) or twist (gybe), as this video from Vestas 11th Hour Racing showed.

Tactical battle

And so it became a tactical battle – more of a bar fight (fought up close using clouds, sail changes and set-ups), than an exchange of ICBMs (fought at a distance, with huge stakes resting on the outcome of each decision). It was Dongfeng Race Team that pulled off the headbutt followed by a foot stamp, breaking clear of Vestas 11th Hour Racing and MAPFRE and building a 12 mile lead overnight, as we can see in Image 4, from 23:00UTC on the 8th November. Dongfeng gybed away from the other two leaders to go west, found a wind shift or stronger breeze, and when they came back together they were nearly ten miles in front.

Image 4 – ©Geovoile

The detail was important everywhere – take a look at Image 5 from 13:30 on the 9th November, half a day later. Team AkzoNobel are up to third place, and have just rolled right over the top of MAPFRE. They were tight with the lead group, and could have stuck with them, but heading into the evening and overnight they drifted to the west.

Image 5 – ©Geovoile

By the time we get to Image 6 from 09:00 the following morning, 10th November, they are a long way west and out of touch with the leaders.

Image 6 – ©Geovoile

It’s a mistake that has led to their current position – fifth, 18 miles off the lead, while MAPFRE are still second. It caused a bit of soul searching onboard, the kind of soul searching that normally stays on board – so very refreshing to see this video posted from their Facebook channel.

Image 7 captures the bigger picture of this battle and the fleet at 13:00UTC on the 10th November, and shows their track over the previous two days (they were at 26N in Image 3).

Image 7 – ©Geovoile

Everyone has had to take at least one more gybe out to the west, but no one wanted to make a big strategic play. The fleet ran south down 28W as though they were on a train line. If I was a financial analyst, and these were a handful of clients about to place their portfolio in my hands, I’d be ticking the risk adverse box.

The possible exception was Turn the Tide on Plastic, who had gone into Stealth Mode at this point, but they made no big moves, and reappeared on more or less the same line of longitude as when they disappeared.

Into the Doldrums

It was in this line astern formation that the fleet hit the Doldrums just after midday UTC on the 11th November (Saturday). At midday the leading trio all had over 20 knots of wind speed from the north-east, with Dongfeng leading MAPFRE by about 11 miles. By the evening the wind had plummeted to 7-10knots and the Dongfeng’s lead was halved, as we can see in Image 8 from 21:00UTC on the 11th of November.

Image 8 shows a very mild Doldrums set-up, all the ugliness and light air is close to the African coast, with the north-east and south-east trade winds apparently seamlessly merging. In these conditions Dongfeng Race Team should have been confident about holding their lead, particularly as the fleet was all strung out behind them, with no one making a play to the west or east.

Image 8 – © Geovoile

It would be reasonable to expect their lead to be eaten away as they hit the light air first, but build again as they moved back into stronger trade wind conditions first – known as the accordion effect. Sometimes it happens like this, and sometimes it doesn’t – there is a fair bit of luck involved when you play cloud roulette in the Doldrums.

And back out…

The wind started to build again on the morning of the 12th (Sunday) and it was quickly back into the low teens. This was a very easy Doldrums transition, as we can see from the accounts coming off the boats. And by early this afternoon, it looks like the chasing pack have managed to lock in the gains they made when the fleet compressed into the Doldrums.

In Image 9 from 13:00UTC 13th November (today) we can see that Dongfeng Race Team are now just three miles ahead of MAPFRE, with Vestas 11th Hour Racing another seven miles back. The whole fleet is solidly in the south-easterly trade winds and now their thoughts will be turning to the South Atlantic High.

Image 9 – © Geovoile

Onto the South Atlantic High

Image 10 shows us the big picture, the fleet racing south towards the eastern tip of Brazil, and south of that, off Sao Paolo, there is a very ugly looking low pressure and frontal system with some pretty brutal conditions on its leading edge (remember the wind rotates clockwise round a low in the southern hemisphere, and anti-clockwise around a high – the opposite to the northern hemisphere). The South Atlantic High can hardly be seen, it’s a long way south, south of Cape Town in fact.

Image 10 – ©Geovoile

All this is happening over 1,100 miles to the south of the fleet, about four days at their current speed. So by the time they get there, the low will have started to clear out and the South Atlantic High will be drifting back north towards its more normal position. However, it does throw up some interesting options for the next week of racing….

Options, or a gamble?

Thanks again to Jess Sweeney for running some of these for me in Expedition’s weather routing software. Take a look at Image 11, which shows the weather situation in a week’s time, midday on Monday 20th November. We can see that the high pressure (the light blue area between Cape Town and Brazil) has started to reassert itself in the South Atlantic, and is gathering strength and moving north, with the low pressure now going south of it. This is as it should be in the South Atlantic, this is the climate zone pattern.

Image 11 – ©Jessica Sweeney / Expedition

But the prolonged absence of the high from this normal position has opened an opportunity for a short cut. The conventional, traditional route is in blue. The plan here is to go almost due south in the trade winds, until you can get round the bottom of the high pressure. Once safely south of it, the idea is to pick up an east-going low pressure system, turn left and ride the low at high speed downwind all the way to Cape Town. The blue arrow shows the boat at midday next Monday, just about to make the left turn.

Now consider the red route. It holds a more easterly course in the trade winds, and cuts across the top of the high pressure to short cut the route to Cape Town. The last time I think anyone tried this was probably back in the seventies, although that’s a bit before even my time.

Shorter by a Hobart

It means going upwind for at least half of the sailing time to Cape Town, but currently, that route is predicted to be 14 hours quicker, and it’s 650 miles shorter – that’s more than the distance of a whole Fastnet or Sydney to Hobart Race…

Will anyone do it? If they want to go for it, they will need to start soon – those routes diverge quite quickly from the fleet’s current position. It would be a very big call. We’re looking at a twelve day forecast, with shaky accuracy towards the back end. It would take a brave man or woman to kick the climatology in the teeth and ignore centuries of tried and trusted practice to try and go north of the South Atlantic High.

My prediction is that they will all be conservative (remember those risk profiles?), stick with tradition and hold their course for another 24 hours… by which time the window of opportunity will likely have closed. This is still a chart I will hang onto though, just to prove it might have worked… 

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