Ocean Racing Magazine - #6 - December 2007 & January 2008 - (Page 26)

TRANSAT JACQUES VABRE there is a little drawing or a bit of a weather chart. The information is kept simple with an explanation of the weather pattern, an answer to a question concerning the strategy is briefly described with some additional advice about how to adapt to a change in the situation. If things don’t go as planned, we ask him to call us or modify the strategy according to the plans we have drawn up." 14 PM 46 A call from out at sea. "Sometimes a racer contacts us to know whether or not he needs to change sails, because carrying out a manoeuvre single-handed or two-handed is no easy matter. Sometimes it becomes necessary, but often it is simply a short transition phase, which does not really merit such a manoeuvre… and which will lead to another a short while later! We have to avoid tiring the chaps after all." 11 AM 30 Another briefing, so that all those involved in the race can reply to any questions easily and quickly. satellite imagery. The pressure readings on the surface allow us to define the position of the weather patterns (lowpressure areas, highs, ridges…) and fronts. They also give us the feeling of the forecaster to have a global vision of the weather. The Grib charts are models that are drawn up with the winds that are forecast, which allow us to feed the routing software and simulate trajectories." necessary to take a less than perfect route, which is less tiring! The more miles the boat has clocked up, the more precise the polars." 20 PM 12 Final reception of the fleet’s position. "The boats send their onboard data every two hours: position, bearing, speed, strength and direction of the wind, the boat’s angle to the wind, atmospheric pressure… That enables us to re-adjust the simulated configuration with reality, in order to know if there are any local changes (clouds) or throughout the area (significant change)." 15 PM 12 E-mail to give the way-point requiring a gybe as they approach the Cape Verde Islands. "Everyone now has the right weather info. The difference is down to small details, with any minor changes from what was forecast. The first boat to react positively to such a small change can obtain a great lead. Changing weather patterns are very important, as they define a new scenario: if a front moves off more quickly than forecast, it is an advantage to be the first to change tack rather than waiting three hours for the wind to come around… " 17 PM 06 Search for further information. "The weather is based around four dimensions, in time and space. Phenomena that happen high up (500 hPa) are felt on the surface later on: that allows us to predict the evolution of the weather and the movements of cold and hot air. At 900 hPa, the wind is not affected on the Earth’s surface or at sea: the flow is purer and gives an indication of the strengthening effect that will reach the surface slightly later on." 12 PM 10 Analysis of the positions in the race and lunch together. "Our role is more strategic than that of a meteorologist: we have to transform weather info into the perfect route strategy. In the inter-tropical zones, you sometimes need to be extremely precise about the weather and the clouds… " 21 PM 44 Call from the IMOCA monohull. "Routing is above all the work of a navigator, but on land… with a bit more comfort and quicker means of getting the information. However, there is also a relational aspect, which is very interesting and sometimes a call can enable us to take the temperature on board, to know whether the racer is feeling good or needs a break or some words of encouragement." 12 PM 50 The team listen and join in with the famous French radio quiz! 13 PM 12 Study of the satellite photos for the passage through the Doldrums. "Geostationary satellites take photographs of the same area of the earth to monitor them minute by minute, which allows animations to be drawn up. Centred above the Equator, their data is not very exact beyond 45° North and as they are 36,500 km up, the resolution is around one kilometre." 18 PM 41 Comparison of the route planning using different software programmes. "We also try out other routing software at this point, in addition to MaxSea, which has been our reference for many years now. This time around, we tried Tactic, Deckman and Expedition to compare their ease of use and results. We always have to keep up with technology in this area to be efficient and train racers on these new strategy tools. I don’t feel that attached to one piece of software, but it must be admitted that the French are quite a way ahead in the area of routing… " 16 PM 06 Positions of the fleet. "They are monitored around the clock, as we are available to racers to answer any questions or intervene if there is any new information, particularly in sensitive areas like the Doldrums, where changes can happen quickly. There is therefore a precise schedule drawn up with basic tasks at precise times." 22 PM 56 Final analysis from the buoys to draw up the way through the Doldrums. "The global weather observation centres provide us with data from coastal stations, ships, which have been approved by the World Meteorological Office, buoys drifting on the ocean or those fixed at certain points (Pirata under the tropics). The American NOOA website offers a huge amount of info from around the world for free, but the problem is you need to sort it all out and choose complementary information. So we must not waste time collecting data, without being able to judge its validity." Dominic Bourgeois 16 PM 23 Reception of the latest weather info from noon GMT. "Of course, we pick up digital charts and weather forecasts at precise times to establish the major tactical decisions, but there is also the data from buoys and boats. Our analysis is chiefly reinforced by observations on the ground and by 19 PM 09 Precise details concerning the trajectory of an IMOCA monohull. "We also have the boat’s polars (with a crew, singlehanded and two-handed) which do not give the same results. Sometimes it is Ocean Racing - december 2007

Table of Contents for the Digital Edition of Ocean Racing Magazine - #6 - December 2007 & January 2008

Cover
Edito
Contents
What they said
News
Portfolio - The news in the picture
Transat Jacques Vabre - Monohulls in power
In the words of the skipper - Michel Desjoyaux, A little bit more
Barcelona World Race - A couple sailing around the world
Imoca - Growth crisis in the Imoca class
Transat 6.5 - A whole series of records
Mini Class - Anatomy of a winner
Multihulls - What sort of trimarans tomorrow ?
Volvo Ocean Race - Second generation
Trials - Mach 45 : an unusual IRC
Match Racing - King Richard
Tactics - A good start
Portrait - Jacques Caraës
Lab - Tubular or wing mast ?
Forty years ago - Chichester, the lonely sea and the sky
Equipment - Shop window
New products - From the drawing board to the boatyard
Opinion - The mirage of worshipping technology

Ocean Racing Magazine - #6 - December 2007 & January 2008