C’est un parcours 5600 milles vers le Nord, de Melbourne à Hong Kong, avec un départ le 2 janvier 2018. Il suffit de jeter un coup d’oeil à la carte pour voir qu’il y a pas mal de terres entre ces deux ports. Pour l’instant, nous ne savons pas si le comité de course décidera de restreindre les options de route, donc nous allons l’aborder dans son ensemble. Dans tous les cas, il s’agit d’une nouvelle étape nord-sud avec…
…encore des zones climatiques à traverser ?
C’est bien cela. Souvenez-vous l’étape 2, les bandes climatiques qui encerclent le globe horizontalement et qui se reflètent en miroir de part et d’autre de l’équateur, jusqu’aux poles.
Qu’en sera t’il cette fois ?
Melbourne possède un climat tempéré. La ville se trouve à une latitude entre le fameux Train des Dépressions d’Ouest (systèmes de basses pressions qui circulent d’ouest en est autour de l’Antartique d’une part, et autour de l’Arctique) et la Zone Anticyclonique Subtropicale (une zone de hautes pressions stable et semi-statique qui s’étend entre 30 et 38 degrés) pour le Pacifique. En assumant que les bateaux partent vers l’est en quittant la baie de Melbourne, ils devront longer les côtes du Victoria, du New South Wales et du Queensland pour ensuite traverser la Mer de Corail.
La principale caractéristique de cette partie sera sa variabilité. Au départ, il est possible que les dépressions du Grand Sud remontent un peu vers le nord et offrent à la flotte des conditions ventées pour contourner le sud-est de l’Australie. Mais si l’anticyclone est bien installé sur la région, le cycle quotidien de réchauffement et de refroidissement de la terre générera des vents thermiques sur lesquels les concurrents devront se concentrer.
Une fois que les bateaux auront commencé à progresser vers le nord, ils trouveront les alizés (des vents modérés à forts qui soufflent de manière régulière du sud-est de l’hémisphère vers l’équateur), et il y a de grandes chances qu’ils en bénéficient pour traverser la Mer de Corail.
Et des îles sur le parcours ?
Beaucoup. Au nord de la Mer de Corail, la flotte devra se frayer un chemin entre la Papouasie Nouvelle Guinée et les îles Salomon.
Et ce n’est pas fini avec les zones climatiques ?
Non. Quelque part dans le nord de la Mer de Corail, les bateaux tomberont sur le Pot au Noir (une région de basses pressions qui enveloppe les océans de la planète à peu près autour de l’équateur et qui est marquée par des orages, des vents faibles, de la pluie et des rafales de vent aussi violentes que soudaines). Cette traversée du Pot au Noir peut s’avérer plus difficile que dans l’Atlantique sur l’étape 2 car à cet endroit du globe, il forme une double ceinture, séparée par une bande d’alizés d’est. Et les îles à proximité compliquent un peu plus la situation météo. Donc la sortie de la Mer de Corail sera sans doute décisive dans cette étape. Une fois passée cette zone, la flotte retrouvera les alizés de nord-est (qui soufflent donc du nord-est de l’hémisphère vers l’équateur) et se lancera dans une course poursuite jusqu’à l’arrivée.
D’autres obstacles ?
Les cyclones tropicaux : Le départ en janvier place cette étape en pleine saison des cyclones dans cette partie du Pacifique et il a des risques que la course soit influencée d’une manière ou d’une autre par un cyclone quelque part dans le Pacifique.
La mousson de nord-est : Une fois que la flotte aura franchi le Pot au Noir, la Papouasie Nouvelle Guinée et les îles Salomon, elle mettra le cap au nord-ouest dans les alizés de nord-est. Elle naviguera donc dans des vents de travers, ce qui laisse présager de belles vitesses et une course en ligne droite jusqu’à la ligne d’arrivée à Hong-Kong.
Cependant… Les alizés soufflent vers la Mousson de nord-est, un vent créé par un flux qui tourne dans le sens des aiguilles d’une montre autour de l’énorme anticyclone située au centre de l’Asie à cette époque de l’année. Et ce vent peut souffler très fort en Mer de Chine Méridionale. Dans les précédentes éditions, lorsque la flotte était contrainte de naviguer vers l’est, au près dans la Mousson de nord-est, les hommes et les bateaux en ont souffert. Cette année, ils arriveront dans l’autre sens et feront cap vers le nord-ouest, donc ce sera probablement une arrivée très rapide et spectaculaire.
Et des histoires de marins dans cette étape ?
Non, car c’est la première fois que la course passe par là, donc tout sera nouveau !
Team Sun Hung Kai/Scallywag gamble out of the Doldrums gives them home town victory.
Team Sun Hung Kai/Scallywag grabbed their opportunity with both hands as they exited the Doldrums on Leg 4, taking a big lead and holding on to it all the way to the finish in Hong Kong.
But not long after the local team claimed the historic win into their home port, tragedy struck when Vestas 11th Hour Racing collided with a non-racing boat on the approach to Hong Kong [read more]
Skipper David Witt and navigator Libby Greenhalgh turned last place into first by taking a shortcut into the trade winds and opening the door to home town glory; let’s see how it unfolded.
Text by Mark Chisnell
Brutal battle When we left the fleet at the end of the last Strategic Review, they were just emerging from a brutal three day battle to cross the Doldrums and get clear into the north-easterly trade winds. If you’re not up to speed on the trade winds, the doldrums and their relationship, then check out the Leg 4 Preview, for the full explanation. If you’re short on time then just know 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.
Unpredictable The Doldrums lie at the centre of these ‘mirrored’ climate zones, in a band roughly along the Equator. It’s an area of flaky light winds, unpredictable thunderstorms and squalls. On either side of the Doldrums lie the trade winds – regular, moderate to strong winds blowing from the north-east in the northern hemisphere and the south-east in the southern hemisphere, and converging on the doldrums.
It was the north-easterly trade winds that promised relief for our beleaguered fleet at the end of the last Review. We left them at 13:00UTC on 11th January in Image 1 with everyone in decent breeze, 10-15 knots across the fleet, blowing from the south-east.
Not the trade winds I don’t want to point out the blindingly obvious, but while a nice south-easterly wind was a welcome relief from the full-on stress-fest of the Doldrums conditions that they had endured for over three days, it still wasn’t the north-easterly trades. There was another wobble, another roll of the dice to come.
We knew that the breeze would strengthen and rotate anti-clockwise to the left, ending up in the north-east. In Image 2 we can see the previously predicted position of the fleet at 13:00 on the 13th January, 48 hours later, with everyone having made a slow left turn to point (more or less) at Hong Kong as the wind shifted to blow from the north-east.
The trend was clear: that the wind would eventually go to the north-east and strengthen was as certain as the sun rising tomorrow morning. The big question was how it would get there and what shifts would occur on the way.
Grabbing the opportunity The weather forecasts are good at smoothing these changes out, but on the water it rarely happens this way with a smooth transition from one state to another; rather, the shifts happen in discrete and often alarming jumps. These are opportunities and Team Sun Hung Kai / Scallywag took one of them and ran with it.
If we go back to Image 1, we can see that all the breeze on the forecast was to the east and the north of the fleet. Everyone was sailing north, or slightly east of north to try to reach it. No one was thinking about turning to point at Hong Kong until they had a stable north-easterly.
The nightmare returns And then, just before midnight on the 11th January the wind started to ease and get very shifty. Take a look at Image 3, from 03:30UTC on the 12th January, three hours after it first started to drop. The Doldrums had reached out with a finger of light air and hauled the fleet back into the nightmare. It was like the final scene from a Die Hard movie where the evil villain comes back to life and has one last go at Bruce.
The whole fleet was now trapped with – and this is the crucial point – worsening conditions to the north, rather than better. There was still some wind to the east of them, but that would mean going completely the wrong way... and there was now wind to the west.
Team Sun Hung Kai/Scallywag (grey) was amongst the first to recognise this – they had the advantage of seeing from the position report that the boats ahead were sailing into lighter winds. And they were certainly the first to be able to do something about it.
The lead six boats were spread around a box about thirty miles square and had breeze from all over the place. Some of these directions made it possible for the boats to sail north-west and some of them didn’t – in Image 3 MAPFRE (white) and Team AkzoNobel (purple) for instance had just two and four knots respectively blowing from the north-west or north, so there was no way they could turn for Hong Kong.
The trade winds arrive... for some Meanwhile, eighty miles or more behind this pack, Team Sun Hung Kai / Scallywag had got a gentle five knot north-easterly, and navigator Libby Greenhalgh knows a good thing when she sees one. They were already moving north-west towards Hong Kong with more breeze ahead of them and were about to hit the hyperspace button.
In Image 4 from 07:00UTC on the 12th January we can see the fleet four hours later now split into three groups. To the north Vestas 11th Hour Racing (orange), Dongfeng Race Team (red) and Team AkzoNobel had finally seen the breeze go to the north-east, and although it was light, they had been able to turn their bows towards Hong Kong and get rolling in a strengthening breeze.
In the middle, MAPFRE, Turn the Tide on Plastic (light blue) and Team Brunel (yellow) had all got a light southerly wind and were struggling to go anywhere useful – one last kick in the butt from the Doldrums. Fifty miles to their south-west, Team Sun Hung Kai / Scallywag still had their light north-easterly and were still making hay towards Hong Kong while the sun shone.
And then the rest It must have been agonising for the trio in the middle, but 14 hours went by before they were finally released from their prison. In Image 5 from 22:00UTC on the 12th January we can see that MAPFRE and Turn the Tide on Plastic had finally got 10-13 knots from the north-east, while to the south-west of them, Team Brunel were still waiting for it to arrive with 1.8 knots of wind speed. It wouldn’t be long, but even a minute is a long time when people are sailing away from you at 13 knots.
Shortcut On either side of this group, the rest of the fleet was long gone. The northern pack had turned for Hong Kong led by Vestas 11th Hour Racing, while to the south-west of them all – shortcutting the corner and sailing a lot less miles than everyone else – Team Sun Hung Kai / Scallywag now led the fleet.
Extending The final piece of the puzzle was how the Chinese team turned their lead of a handful of miles at this stage into seventy plus miles. In Image 6 from 01:30UTC on the 15th January we can see the reason for the extension.
I’ve taken the wind arrows off the chart because the tracks are easier to see. If you look in the table everyone now had a trade wind of between 61-67 degrees direction and 16 to 25 knots. They were all sailing True Wind Angles (TWA) ranging from 125 to 140 degrees (depending on their wind speed) – so they were all sailing downwind, Velocity Made Good (VMG) angles. The problem that all the boats to the north of Team Sun Hung Kai / Scallywag had was that they could not get to Hong Kong without gybing and spending time on port.
Painful gybe The tracks show that everyone except the leader and Team Brunel had spent time on port by now, and every time it happened they were barely making any progress towards the finish line. Meanwhile, the leader was almost pointing at Hong Kong and gaining leaderboard miles at a spectacular rate.
And so, despite a man overboard and being positioned to the west where the wind was predicted to be lighter, Team Sun Hung Kai / Scallywag moved into a very handy lead. It would have been a lot closer if the trade winds had settled at 45-50 degrees, and no one had needed to gybe, but they didn’t... and so the Scallywags have a tremendous opportunity to lead into their home town.
Opportunism Team Sun Hung Kai / Scallywag’s move was a classic piece of opportunism. They were last by a very long way, and had the benefit of seeing from the position reports that the leaders were sailing into lighter winds ahead, not stronger. It made perfect sense for them to turn left, as they had little to lose. Sailing into the same hole as the boats in front of you rarely pays. The wind gods gave them the power to do something else, and they did it. The rest may well be history.
Up to date In Image 7 we bring it up to date at 13:00UTC today, 16th January.
Team Sun Hung Kai / Scallywag led by 73 miles. The fleet had further converged, and the rest of the podium had been settled in favour of Vestas 11th Hour Racing who led Dongfeng Race Team and then Team AkzoNobel after weaving through Micronesia. Vestas 11th Hour Racing had a lead of nearly 20 miles, with Team AkzoNobel another 16 miles behind Dongfeng. There was a big gap of over 60 miles to the final trio, led by MAPFRE who were in turn a long way ahead of Turn the Tide and Team Brunel.
North-east monsoon The Scallywags were leading into stronger wind, already having five knots more than anyone else in the fleet as they sailed into the north-east monsoon first. This is a wind created by the clockwise flow around the huge high pressure that builds up over central Asia at this time of year. It would normally be expected to drive the fleet home at pace, but as we mentioned at the end of the last Strategic Review, there may be some disruption this time around.
A high forms In Image 8 we can see the boats' predicted positions and the weather at 11:00UTC on the 17th January.
The area of high pressure that we mentioned in the previous Strategic Review is still forecast to form, and we can see it here to the north of the fleet. In this forecast it then fades and drifts away to the east, and lets the north-easterly flow down the South China Sea resume. The high pressure will produce significant wind shifts between now and the top of the Philippines and that means opportunity for the boats behind. The fleet currently have a 70-80degree wind direction. It’s going to lighten and shift to the north-east as the high pressure forms.
Play the shifts The navigators won’t want to get too close to the high, and the predicted routing calculation suggests that TSHK / Scallywag gybes to port for a while. The idea is to get away from the high. In Image 9 we can see the predicted route, positions and weather for 07:00UTC on the 18th January.
The motion of the high pressure has pulled the wind back to the east, and lifted the boats off their course (visible in their curved tracks). It means the fleet will have to gybe to get to the top of the Philippines, where they will see another wind shift back to the north-easterly for a fast ride across the South China Sea to Hong Kong.
One final passing lane If there is a passing lane left on the race course it’s in this section up to and around the top of the Philippines. However, the gaps between most of the boats are substantial, and the strategic parameters look solid.
It will be more efficient to do the port gybe in the easterly wind, and the starboard in the north-easterly. And with the best breeze to the west in the Luzon Strait, it looks like the routing is suggesting the only way to go – hold onto starboard until a gybe to port takes you to the northern tip of Luzon, then gybe back to head for the finish.
All this could change if the high moves closer to the race track, or sticks around for longer, and that’s quite possible. It’s also going to be rough in the Luzon Channel, and they will all need to keep the boats together. Essentially, it’s Team Sun Hung Kai / Scallywag’s to lose at this point – only a mistake by the boat in front is going to create a real passing opportunity for the boats behind...
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