8:08 AM Tue 24 Mar 2009 GMT
Light winds are creating a headache for navigators aboard the three lead yachts in the Volvo Ocean Race.
Although they are using the same navigation software from Expeditionwe are running at Sail-World, the navigators only have one source of weather data, supplied by the race organisers to all yachts, but we have two sources from PredictWind
In fact we have more than that, because there are three weather locations between the boats current position and the finish at Rio de Janeiro so by checking each we can look at six options - and then optimize the courses off each, to try and find the fastest path to the finish.
Most of the optimizations are predicting quite a close finish, however the optimised tracks swing between favouring an inshore course and hanging a sharp right and going offshore.
Complicating the situation is the fact that race leader Ericsson 3 has sailed at right angles to the direct course to Rio de Janeiro and has made a move inshore. It is not clear why she has done this, and the other two yachts Ericsson 4 and Puma Racing have stuck to a more direct route.
Below: Ericsson 3 has made a right angle turn towards the South American coast away from her two nearest competitors. Course optimisation says she should swing nack onto a direct course for Rio.
Below:According to the weather data there are light winds only from varying directions all the way to Rio de Janeiro. The lighter/whiter the colour the light the wind. A full width barb indicates 10kts of wind, half a barb, 5kts - the barb end has its back to the wind
Below:Two course optimisations taking wind data at the same point on the course, but from two independent sources, showing quite different routes to the finish. The race boats only have wind from one source - which could be either of these, or something completely different again. The navigators on board would probably not be aware of the potential or real discrepancy between the feeds. The reason for the variation in courses is because the wind is so light and variable in direction. Just visible to the right is the advancing South Easterlies, which will probably come in just behind the race leaders, and would reduce the variation between the course projections. However as one model sees these as being stronger than the other the yachts are directed more towards the area of stronger wind to get a faster ride to Rio even though they sail more distance.
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The images used in this story have been generated by Expeditionwhich is a tactical and navigation software application which has been developed by veteran Volvo Ocean Race navigator and Whitbread winner, physicist Nick White, initially for his use in the 2001-2 Volvo Ocean Race with Team News Corp and the Stars & Stripes Americas Cup team.
Since then, Expeditionhas been continually refined by a core group of world-renowned navigators and two-time America's Cup winning navigator Peter Isler has consulted closely in the development of the system. Expedition supports more instrument systems, is easier to use and has the most powerful and useful functions for the racing navigator.
Expedition is now has PredictWind integrated into the application as an option for PredictWind subscribers.
The wind data and prognosis used to produce these images also uses software developed by PredictWind, an application developed by Jon Bilger a top NZ youth and Olympic sailor who turned his hand to wind and weather prediction, and helped Alinghi to their outstanding victories in the last two America's Cups.
Now that same technology is available to the weekend sailing and club racers, the cruising fraternity or professional sailors around the world. Select any region in the world of interest to you and PredictWindwill monitor the area for you and provide updated predictions on demand.
PredictWind is a subscription system, with a number of options. While some may feel the wind is free, the ability to get a five day detailed wind forecast for an area of interest creates great peace of mind, allowing forward planning and decision making to be made with some certainty. The time and money saved through being able to work with a high degree of confidence, is more than offset by the relatively small cost of the subscription.
But don't take our word for it, get PredictWindnow and have a 30 day trial for free, and see for yourself.
by Richard Gladwell, Sail-World.com
Click on thumbnails to enlarge and find more photos:
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