Volvo Ocean Race- The Riddle of the Routes + Video
by Richard Gladwell on 12 Nov 2011
Less than a week into the Volvo Ocean Race, the classic is proving to be what everyone expected and more.
Groupama Sailing Team sail along the African coast during leg 1 of the Volvo Ocean Race 2011-12 Yann Riou/Groupama Sailing Team © /Volvo Ocean Race http://www.cammas-groupama.com/
Yes, there was the first night shenanigans, which have too often marred the start of Round the World races of various types out of the Med and Europe. While those incidents took some of the edge off the competition, the race on the water is proving to be what many expected.
In the 2011-12 Volvo Ocean Race, what the fleet lacks in size it more than makes up in quality - as four of the top trans-oceanic crews in the world go head to head in an arm-wrestle that has pitted computer routing against gut feel experience.
Conventional wisdom is to head on a more westerly course, taking advantage of stronger winds that usually prevail. 'West is Best' is the long standing mantra.
The computerised routing systems on board the boats - which use a race organiser supplied stream of weather data - have also been advocating a similar route to the west. Quite how much you believe the computer is where the onboard tactical navigation experience kicks in, and there's plenty of that in this high quality fleet.
Several days back the fleet were relatively bunched, but had to decide whether to move west, or hold on.
They split into three groups. Two boats Telefonica and Puma moved west. Camper elected to hold. Groupama skippered by round the world record holder, Franck Cammas took the unconventional route hugging the North African coast.
Conventional wisdom and computer routing has it that Groupama's course is the road to nowhere. All routing recommended Cammas and his crew to turn right and catch up the others.
Three days ago on their 8 November report Groupama described their routing logic this way: Boosted by his wealth of experience in transatlantic races, Franck Cammas, with the support of his navigator Jean-Luc Nélias, didn't think twice about striking out on his own, on a different course to the more familiar faces in the Volvo Ocean Race. Indeed, as soon as they were through the Strait of Gibraltar, Groupama 4 slipped along to the south-west in a bid to hug the Moroccan coast. There were two reasons for this. The first was to make the most of the thermal breeze often created by the presence of the Sahara desert. The second was due to the tradewinds which, though weak, are positioning themselves off shore of Essaouira. This is around 120 miles ahead of Groupama 4's current position and hence well in front of the first islands that make up the Canaries archipelago.
They did rather nicely, thank you.
The routing did show great gains initially by this easterly course and hence why Groupama selected it - maybe hoping the long range forecast would be wrong.
On the previous report (0655GMT on 11 November), Telefonica was reported by VOR as being 226 nm behind Groupama, with Puma 237nm back and Camper 293nm in arrears.
Enquiries of the Volvo Race Office revealed the the basis of their calculations are the orthodromic distance from the boat to the waypoint at off the Brazilian coast, plus the distance to the waypoint on the finish line at Capetown.
In plain English it mean that the Great Circle distance is used to measure from competitor to the the Brazil mark and then onto Capetown. For and explanation of the orthodromic distance http://en.wikipedia.org/wiki/Great-circle_distance!click_here
Running the boat positions through a routing package from www.predictwind.com!Predictwind produces quite a different result.
PredictWind´s Weather Routing is the best tool, to really evaluate the expected outcome of the leg, or to a give gate or waypoint, such as the immediate mark off the Brazilian coast. By using the latest forecast and the boats performance curve (polar), the mathematical algorithm looks at all the possible courses to calculate the best and fastest route.
PW can even take into account current and waves. Obviously the result is only as good as the forecast, and the race boat achieving boats speeds predicted. So it is not perfect, but far and away better than speculation and conjecture.
In fact the PredictWind forecasts and routing have been predicting a westerly course to be the fastest, even before the race started, and every forecast since. However Groupama have a very different plan so it will be interesting to see who is correct in five days time.
On that basis we can get arrival times and distance sailed to the Brazil gate.
Four different wind forecasts are used to display four optimal courses - showing the fastest route. Generally the forecast and route can be trusted up to five days, but less certain after this. If all four forecasts are showing the same result, as is the case for this race so far, you can have greater confidence in the results.
On that basis, Groupama does have the least distance to sail at 2086nm to Brazil at 0655 GMT, with Telefonica/Puma on 2274nm and Camper on 2370nm by one wind feed/route. By the other the distances are Groupama 2131nm, Telefonica/Puma 2434nm and Camper 2490nm to sail to the Brazil gate, as of 0655hrs on 11 November GMT.
Quick picture is that both routes have Groupama having the shortest distance to sail, with a lead of 188/304nm over Telefonica and Puma; and a lead of 284/359nm over Camper.
The Volvo Race Office margins at this same time had Telefonica 226nm further from the Brazil gate/Capetown, than Groupama, with Puma in 237 nm distant and Camper 293nm. The Volvo Race Office calculations are within the range of the two distances, and tending towards the shorter end of the scale.
But quite a different picture emerges once the times to the Brazil gate are calculated, and the effect of stronger winds to the north are factored into the calculations.
Telefonic, Puma and Camper all come through in a stronger wind pattern which has Telefonica first around the gate on 17 November at 1230hrs or 1730hrs on the second wind feed. Puma is next, with Camper projected to pass the gate on 17 November at 1530hrs or 1915hrs.
While Camper is well back at present, she does catch up - and on the current weather data an routing will round the gate about three to six hours behind Telefonica.
Groupama, although with less distance to sail, has to traverse the Doldrums at a wider point than the other three.
That is seen by the Predictwind routing and in short Groupama, on the face of it has to sail a shorter distance in lighter winds, which adds up to a longer time.
But if nothing else, Groupama has so far confounded the conventional tactical approach to this part of the Atlantic. Many pundits believe she should have been history by now, instead she leads the fleet by over 200nm and the routing predicted that she would be a ahead by about this margin, at this stage of the race.
Quite how this leg unfolds over the next week will be intriguing to say the least, and the battle of the best brains in trans-oceanic racing is fascinating.
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