Models predict close finish to Volvo Ocean Race

6:31 PM Mon 23 Mar 2009 GMT

'Media Crew Member Rick Deppe used a 30 second exposure on his SLR camera, clamped to the boat to create these amazing shots of PUMA Ocean Racing.' Rick Deppe/PUMA Ocean Racing/Volvo Ocean Race &copy Click Here to view large photo

The course optimisation and projected position applications used by Sail-World, the same as the navigators use aboard the actual Volvo Ocean race yachts, is predicting a close finish to leg 5 of the Volvo Ocean Race.

The software Expeditionand PredictWindcan use weather from two different sources, and the trick is to evaluate the outcomes from both, compare the results, and when there is a significant gap, then a choice has to be made. However when the two are predicting a similar outcome then the probability of that out come occurring is generally very high.

Projected finish positions using one set of wind data as at 1600hrs (NZT) or 0300hrs UTC on 26 March 2009 - Predictwind.com-iexpedition.org Click Here to view large photo

To date there has been some discrepancy between the two outcomes, and we have been placing more faith in the source that has been more reliable in the past, even though it shows the yachts sailing some quite extreme optimised courses.

Today however the output from the two models is very similar.

Both show the last stages of Leg 5 developing into a very close run affair - with one having all three leaders in a near match race at the end of the 12,300nm leg.

Both projections agree on a finish time of around 0600hrs UTC on 26 March or 1900hrs (NZT) on the same day.

The reason for the sudden catch up is not that clear - and it must be said that light winds are expected in the race area today.

Projected wind ahead of the Volvo Ocean race fleet as at 0700hrs NZT on 24 March. The white areas indicate light wind - of which there is plenty ahead. - Predictwind.com-iexpedition.org Click Here to view large photo

Both Ericsson 3 and 4 are heading inshore slightly and get caught when Puma racing picks up a stronger breeze blowing offshore and is able to sail a more direct course in winds of 20knots or more, while the other two come back out onto the direct course wasting their inshore distance.

At 200nm from the finish, the three yachts are separated by just 20nm in a radius from Rio de Janeiro, and 40nm out the three yachts are separated by just nine miles. Certainly they will be within sight of each other for the last 200nm.

However as we all know, wind and weather are notoriously fickle and this prognosis could well change, as weather and wind systems change or behave in a way that was not predicted. Sail-World is monitoring the forecasts and projections every six hours (taking into account two race skeds) weather information is updated every 12 hours.

Below:A snapshot of the positions from both sources of wind data used by PredictWind, showing essentially the same outcome. Both also show a finish to the race within three hours of this shot. The lower shot is taken three hours ahead of the upper, and is based on an updated sked (three hours later). The two are now very similar.

Projected finish positions using a second independent set of wind data as at 1600hrs (NZT) or 0300hrs UTC on 26 March 2009 - Predictwind.com-iexpedition.org Click Here to view large photo

Projected finish positions using a second independent set of wind data as at 1300hrs (NZT) or 0000hrs UTC on 26 March 2009 showng a nine mile separtion between the three yachts with over 40nm to sail.

PW260309-1300NZT-wind-zoom-gfs.JPG - Predictwind.com-iexpedition.org Click Here to view large photo

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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