Vendée Globe - IMOCA Performance Analysis and Optimisation with Nicolas Andrieu - Sport acquatici - NAUTICA REPORT
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Vendée Globe - IMOCA Performance Analysis and Optimisation with Nicolas Andrieu

Vendée Globe - IMOCA Performance Analysis and Optimisation with Nicolas Andrieu

Sunday 10 February 2019, 11H37

For a skipper and team which are aiming for a decent sporting performance, empirical analysis of the the performance data and corresponding behavioural characteristics of an IMOCA is essential. And it is increasingly important when it comes to the analysis and understanding of the new generation foiling ‘flying’ IMOCAs.


On the Charal team Nicolas Andrieu is one of the technical team members whose responsibility it is to gather the data and analyse it. The objectives are to realise the full potential of the boat on all points of sail and wind strengths, to make incremental changes in appropriate steps at the right time, and to maximise the reliability of the boat and the requisite hardware. 


How do you organise things within the team and how does the data capture and analysis take place?


"There are two of us. Philippe Legros deals with the performance analysis -  in the usual sense of the words - so collecting all the data from the water, that is the configuration of the sails, ballast, rig settings, speeds and heel angles. All this is used to configure the polars (the theoretical target speed and wind angle) for the boat which are the foundation data for routing and as a performance index.


Then my job is in two parts. The first is to make sure we don’t break things or the boat. With our large foils there is a critical structural aspect. Our sensors allow us to have indications on the stresses placed on the rigging and the foils. We looks to maximise the best configurations which don’t overload the boat.


The second part is to provide ideas and the required analysis so we can consider changes. We have the ability to modify the boats quite significantly. Charal is a relatively new boat and many of the choices were made on the strength of the numerical modelling of the architects. The idea is to make a comprehensive analysis and inventory after each sail. In itself that is a huge job. Each change we make has positive benefits some times but with losses in other areas. The challenge is to get the equation right and to make the right choices.


So what is your typical methodology? 


"The most important thing is going sailing, time on the water. So far now we are still early in the learning phase as I would say we have sailed about 25 days including 15 which were dedicated to the pre start period leading up to the Route du Rhum Destination Guadelpupe, during this phase it was very much about establishing the base lines, there no real question of performance. The returns we got in terms of learning the performance and making positive changes were quite limited then. So there are things we will need to re-learn in the spring, expanding our knowledge quickly and seeking gains through possible mods.  We are still discovering things Jérémie knew about his old boat. There are speeds and conditions which we have not yet encountered much yet, like in big winds and big seas – we have not been there yet. But to start with we must have an understanding of the boat in all conditions to make progress. "


What tools do you use?


"We have a hundred sensors on the boat. The traditional, usual sensors of key sailing measurements (wind, heading, speed etc ..), but also measures of heel, trim, pitching, rudder angles, the position of the foils.


Nicolas Andrieu

The latter are equipped with fibre optics to measure their deformation. Plus all of the rig is fitted with load sensors.Then we use analysis tools and software to detect relevant information in all data collected in navigation.


The software Sailing Performance which is used by Philippe Legros allows to manually input and record the boat configurations that are not measured and transmitted directly by the sensors, it is a sort of pro forma display into which you enter the configurations of sails, ballast , the state of the sea etc. Race Replay (timeline and the track of the boat) allows to us review a whole day of sailing and to select and analyse the key phases. These phases can then be analyzed in a database, Query Performance, allowing the final list of optimum configurations. If one wishes detailed analysis on very precise parameters, one can also extract real time data and analyse them in Excel, I maybe do this in isolation for a particular load sensor. To identify the relevant phases, you go from the general set up to specific details. "


What are the expectations of the skipper Jérémie Beyou in this area?


"These boats have so many different settings and configurations for one person, especially someone who – by the nature of solo racing – is usually working in a state of advanced fatigue. The idea is to simplify his life so that in each configuration he has only a handful of parameters to manage to ensure that the boat is at least at 90% of its speed potential. And one objective here it to make sure the lowest level of performance is never below 70% of potential as if this is the case then there is some setting which is badly wrong. And here this must be done by identifying the parameters which has the greatest bearing on the performance in those conditions, say. 
But for his first race, the Route du Rhum-Destination Guadeloupe, Jérémie's first aim was just to have polars which were accurate enough him to run his routes and therefore to have confidence in his strategy. "


Philippe Legros and you were originally racers and sailors. How important is it to have this type of profile for the work you do today?


“The advantage is our ability to have a global understanding of how the boat works: we can interpret things and go beyond the info from the sensors and understand what has not been recorded. For example, the fact that I have done a lot of Moth foiler sailing taught me a lot and got me thinking about things that otherwise I wouldn’t have worried about, if I had stayed in front of my computer. About the effects resulting from heel, trim. It meant I felt things and had ideas that had nothing to do with simple calculations.”


Did you discover anything surprising about the performance of this boat?


“The answer to that is top secret! What I can say is that we discovered she was an amazing boat. A boat that really flies… What was required was finding ways to sail taking into account this new factor. The foil has a major role in terms of stability. That changes a lot of things in the way we trim. But she certainly feels crazy and it’s addictive.”


You are the first boat in the latest generation to be built around the foils… was that an advantage or drawback in relation to your rivals?


“We shall be ahead in terms of understanding the boat and her use and we will be at the vanguard of foil design. We are with version V1 of the foils, but I can’t say today how many versions there will be. The consequence is that the others will be using us as a reference. However, the Vendée Globe will always be a long, solo race, with plenty of other things to worry about other than simply performance. We believe that having launcher her early, we will be able to get a lot of the potential from the boat during the round the world voyage after ensuring her reliability and getting to know her in detail.”

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