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SailGP: Teams crunch the numbers in search of performance gains

SailGP: Teams crunch the numbers in search for performance gains

One aspect of the new SailGP global circuit currently two events into its inaugural season is the open sharing of vast quantities of performance data gathered whenever any of the six boats go racing.

With training time on the high-tech 50-foot foiling catamarans rationed to the week before each regatta, effective analysis of the available data has become a key tool for all of the teams as they race each other up the steep learning curve towards mastering their boats.

To find out more about how this all works in practice we quizzed Joe Glanfield and Emily Nagel   – respectively the coach and performance data analyst with the British SailGP squad – on the way they work together to make the most of the available data.


YRL: Can you each explain your individual roles with the team?

Emily Nagel: The GP50 catamarans have an unprecedented volume of data coming off of them – everything from boat speed and true wind angle to the rake of the boards, wing settings and much more. I take this mass of information and simplify it to be useful to the sailors and help identify where the team is strong and where improvements can be made.

Joe Glanfield: I am the team coach so generally responsible for the team developing as quickly as possible and helping them identify and execute what will be important on a race day. In practice this means bringing structure, facilitating conversations, setting goals and reviewing. Often it also involves challenging their thoughts and filtering out what isn’t going to make a difference.

YRL: Can you summarise how you work together?

Emily Nagel: I work closely with Joe and the sailors. I take part in all the briefings and debriefings, so before the boat goes out on the water I know what the boys are trying to focus on.

Every time we line up with other teams for training or racing I will be onshore with all my computer screens watching the numbers so that I can feedback in real time to Joe any differences in settings and moding between the teams. At the end of each sailing day I take a look at comparisons of all the boats in a straight line and in manoeuvre’s and compile a report that can be used in the team debriefs.

Joe Glanfield: Emily provides the facts that give us an objective rather than subjective view of what is going on. Likewise I provide her with information on what I am seeing and also flag performance questions in situations where we have an issue, but we don’t know the cause. With access to data from all the teams she can then often find out another layer of detail to help us find solutions.


YRL: Where are each of you situated when the crew is out practicing or on a race day?

Emily Nagel: I am based onshore with all the computer screens following the numbers, it’s definitely a different point of view than what I’m used to.

Joe Glanfield: On a training day or race day I will be on the water with the race team whilst Emily will remain onshore with her computer. But we are in contact by phone.

YRL: What data is available to the teams and how do you physically receive it?

Emily Nagel: The data is open source between all six teams and is available online in real time (thank you Oracle!). We have a data analysis program called Grafana into which is fed all the real time data. I also use KND Sailing Performance software for post analysis.

There are approximately 1900 data channels, most of which we don’t actually use as many are for all the individual electronics (for instance, each button has its own channel). We can then select in Granfana the channels that are relevant to what we want to look at.

Typically I will have a dashboard of numbers set up tracking the wing setup, foil setup and a page comparing all the boats at once.

Joe Glanfield: A huge amount is measured. Emily looks at the data coming off the boats with a focus on our team, other high performing teams, or teams I have a question about. Whilst out on the water I will receive information from her on my phone.

SailGP: Teams crunch the numbers in search for performance gains
Image © Lloyd Images/SailGP

YRL: Is all the data issued to all the teams or do you have to request what you want?

Emily Nagel: 
All the data is online open to all the teams.

Joe Glanfield: All the data is available to everyone, but we need to be quite skilled as a team to pick through it and look at the things that are meaningful. When it comes to data like this, more isn’t necessarily always better!

YRL: I imagine there is a mind-boggling amount of data? Can you give an indicative size? 

Emily Nagel: 
There are around 1900 data channels which can be downloaded at a frequency of 1 HZ. For efficiency though I am normally only looking at around 20 channels dependant on what the team are focusing on. So a typical log file for a single training session will be around 60000 KB.

While the team is on the water I’m following the live data and once they come back ashore I download the full log file for further analysis. I can also go back and look at data from any of the training days all the way back to their first sessions in Sydney.

YRL: What are the key elements that you have been focusing in on?

Emily Nagel: Straight line speed has been a big one for us. We feel we have the edge on the other teams upwind with our high mode but are still working to match Japan and Australia downwind.

Manoeuvres have also been a big focus as well. In this fleet whoever is able to do dry laps is going to win. We’ve done both foiling tacks and gybes but still lack consistency with the tacks in the lighter breeze. So we’ve been looking a lot at data from the other boats to see what they are doing onboard.

Because the boats are so new and there are so many different setting options no one knows exactly what modes to select. So we have been testing different setups and comparing them to see what is the most effective.

Joe Glanfield: For me, what people have been doing with the foils has been really significant, along with the timing of adjustments in relation to manoeuvres and wind speed changes.


YRL: How do you communicate what you have learned with the rest of the team?

Emily Nagel: Anything I notice while the team is on the water I will message Joe about so that he can feed it back to the team while they’re out there. At the end of each day though, in the team debrief I will go through a report covering the day’s session, the best manoeuvres and make comparisons with other teams. We combine it with the video Joe takes on the water to help relate the numbers to what is actually going on.

Joe Glanfield: How we communicate something depends on what it is. Sometimes it is something we need to let them know right there and then on the water, or sometimes it can wait for the debrief alongside some video, or sometimes even in a written report.

Whatever it is we are talking about we always try to consolidate it by all talking it through and deciding what actions are required based on what it is we have learned.

YRL: Can you share some examples of things you have learned and how the crew has adapted their sailing style or setup?

Emily Nagel: Some of the biggest things we have learned have come from looking into the numbers after a crash and figuring out why it happened. We had a big nose dive in our first few days of training in San Francisco and after training we sat down with Dylan (helm), Stu (flight controller) and the systems engineers to pinpoint why it happened.

It essentially came down to how the new flight controller setup works.  After that discussion the systems engineers decided to put in new limits for how much the rake the boards can be adjusted to when being dropped.

We have also been looking a lot at how to consistently foil through manoeuvres. A lot of it has to do with the entry and exit angle. Looking at the angles sailed by the Australians and the Japanese – who have the most experienced GP50 sailors onboard (all ex America’s Cup sailors) we knew we needed to sail wider into and out of tacks. It sounds a simple enough solution but the numbers helped to reinforce our ideas and highlight the importance of some of the smaller things.

SailGP: Teams crunch the numbers in search for performance gains
Image © Lloyd Images/SailGP

YRL: Have you discovered anything that has really surprised you?

Joe Glanfield: The biggest surprise has been those massive tacking angles to ensure entry and exit speed.

Emily Nagel: What I found the most interesting was the differences between all the wing trimmers and what they are changing with the wing into and out of manoeuvres. Every team is different. Some trimmers will keep wing twist constant in and out of a manoeuvre and play the sheet more while others will increase twist for the exit of the tack.

YRL: Where are the big gains to be made in the fleet based on what you have learned?

Emily Nagel: Stability is the key, if you aren’t stable going into a manoeuvre the hull will end up touching down. A team that can do dry laps will be near-impossible to beat and stability is a huge part of achieving that.

Joe Glanfield: For us there is still a lot of headroom to gain in platform stability – ride height, heel and pitch consistency.

YRL: Emily – you were involved on the design-side with these boats during the last America’s Cup with Softbank Team Japan, how different are the boats now after their modifications? Can you explain the key differences?

Emily Nagel: On the outside the only noticeable difference is the paint job, but inside it’s a whole new beast! You can see that there are only two grinders now and that’s because two pumps were installed. The grinders are only providing the muscle for controlling the wing sheet, everything else is done by the pumps. This means that the control of the boards is much more efficient as it’s almost impossible to run out of oil, just by changing the rake or moving the board up and down.

Also, in general more can be adjusted with full control of the rudder rake now while sailing and adjustment of different settings for dropping the boards (the sailors can choose from three modes that alter the rate of the board drop: whether it goes down by freefall or whether the pump or the accumulator is used).

There is also a huge amount of tech onboard, not just the new flight controller but a very advanced wing display designed by the geniuses at Artemis Technology. There are electronic controls on a lot of the systems as well allowing sailors to choose the rate at which the foils are adjusted and setting speeds and angles at which the boards are raised.

We joke with their systems engineers that if they wanted to they could turn the autopilot on –  there isn’t one of course, but if anyone could make one these guys could!

YRL: Joe – how does having this data available to you change the way you carry out your role as coach?

Joe Glanfield: The biggest thing is thatin SailGP there is more to check against after you notice something and want to see what the truth is. In Olympic coaching there is a lot of subjectivity and it is a real skill to unpick what you see. In some way the data reduces that but increases the need to be able to pick through and simplify a lot of information to manageable development goals for the sailors.

There is also another stage of communication, which is making sure Emily has a picture of what is going on the water and is free to tell me what the data is telling her. There is also more to filter, like is what the data is saying helpful? Also what is the root cause of a problem and what needs to be addressed first?

SailGP: Teams crunch the numbers in search for performance gains
Image © Lloyd Images/SailGP

YRL: What other questions should we have asked you and is there anything else you would like to comment on?

 Joe Glanfield: An important question is whether the data analysis is significantly accelerating our learning and directly resulting in a higher performance from the team? The answer is absolutely yes, as being able to see data from the other boats is an absolute game changer and is a key reason why our team’s improvement has been so quick.

Emily Nagel: I think one of the important things for people to realise is that data is becoming more and more important in the sailing world. Many are still strongly of the belief that it is all about instinct and feeling and that numbers can just be a distraction. That certainly is true to a certain extent, but if it is done carefully and used as a tool data analysis can be extremely useful.

The provision of open data between the SailGP teams creates a very positive learning environment in which everyone is improving currently at an exponential rate. There have been many complaints/criticisms that not everyone has fully mastered the foiling manoeuvres yet, but if you think back to the America’s Cup and how long it took the teams to work out foiling tacks on the AC45’s, it was years of development and training.

These SailGP teams only started sailing six months ago. Before the first event in Sydney many had only had 11 hours of training time on the water. I don’t think that would have been possible without having the performance data available and the steep learning curves we are seeing are only possible because the teams are able to learn from each other in a way that in all other regattas is not possible.