Forced to retire from the 2020 Vendée Globe after dismasting, Nicolas Troussel joined Mindelo in Cape Verde. Since then, the boat has been repatriated to Lorient for a winter refit. Amongst which, a reinforcement of the hull. A refit that had already been carried out in September 2020, following the sailings carried out during the year.
Aware that they couldn't sail much due to the health crisis, the team had decided to sail out of the race in all possible seas and on all possible fronts to " shoot the boat." as much as possible.
Why reinforce the hull of the IMOCA Corum l'Epargne?
"On the one hand, there were internal impacts in a few places on the hull which had altered the sandwich. We had already reinforced the hull last September, following last year's sailing, particularly when we sailed in 35 knots. On the other hand, we're exploring new horizons and discovering new boat behaviour with these latest generation foilers. These hull problems do not only affect these new boats, as even boats without foils have encountered hull problems in the Vendée Globe.
Our boat is going to evolve in its behaviour, so we've decided to make a more global reinforcement. Right from the start of construction, our specifications were to build a boat that was as solid as possible, even more so than the 2020 generations already reinforced.
We have to keep in mind that we are exploring new shipping lanes. You don't sail in protected waters like the America's Cup, you don't have a load-bearing plan like the Ultimate."
Difficulties in modeling the boat's behaviour
Today - even if it has always been the case - the boats are subject to violent impacts, with the difference that today, the IMOCA boats are getting faster and faster, perched on their big foils.
"There are several notions of impact, it's not just when the boat hits the waves, it's also the way the waves break over the hull. For the moment, the notion of impact is still unknown and impossible to simulate. All it takes is a small angle of heel, a small wave... Even a very slight impact can have different impacts. It is well and truly p read complex that just a boat on the water, there are phenomena of impact, torsion... It's difficult to model boat behaviour, we don't know how to model things perfectly. But that's what makes it exciting."
When we designed Corum, we did things in the most responsible way possible, conscious of sending one or more sailors far from land, offshore, and above all with the aim of finishing the race. And the solidity of the boat is important. With Michel Desjoyeaux and Juan Kouyoumdjian (editor's note: the boat's architect), we wanted a strong and reliable boat. They have taken significant margins, but they are proving to be insufficient in certain areas of the boat.
In spite of all the computer tools and developments, it is difficult to model the boats' behaviour perfectly. We are thinking of using conservative safety coefficients, but we realise that they are not sufficient. We can't blame anyone. We're exploring new modes and new horizons, it's part of our sport."
If the Corum l'Epargne team therefore took the option of reinforcing its hull, it was a deliberate choice on their part, and not an IMOCA class instruction. Moreover, the team regularly carries out ultrasonic inspections of the hull.
Why turn the boat over for repairs?
But then, why turn the boat over to do the work? As much as we were used to seeing boats lying on their side, but upside down..
"We flipped it over because we wanted to see if it was as pretty upside down as it was inside out. And then there's no more 180-degree tests." is having fun Greg Evrard.
More seriously, it is above all an ergonomic choice, as the Team Manager explains.
"We're going to do the work from the bottom of the hull, from the outside. So it's much more ergonomic to have the boat in that direction. It also makes it possible to use gravity for everything that is impregnated. It's an extra source of quality."
To reinforce the hull of the IMOCA, the team has chosen to replace the core with a denser foam, to reinforce and homogenise the hull. Although structural reinforcements had already been applied to the bow of the boat last year, it is not impossible to add more, even if there is no "structural necessity." With this work, the boat will gain a little weight, which is not a problem for Greg Evrard
"The soul is denser, so it's gonna have a counterbalance on the weight. But that's not the point. Between reliability and weight, we've always chosen reliability. We're not reckless gamblers. When I hear that we decided to build a Formula 1 of the seas, it's not true, the primary objective is to have a solid boat to sail around the world.
Boats of this generation are the strongest boats ever built up to that point, but as they go faster, and with airborne notions, you have to deal with that, and that's the hardest thing to model. It affects all categories of boats, not just those with big foils. The new foilers don't have a monopoly on structural problems. All boats of all generations have always had structural problems.
The case of foils
If the boats need to be reinforced to withstand the impacts, it is also because they go much faster than before, thanks in particular to their foils.
"Today, we're trying to move faster. The foils are absolutely great and we're nowhere near the end. The preparation of the sailors was too short due to the health situation and the technical exchanges were reduced. The evolution of the boats is magical. I'm passionate about it and it's done in a reasoned way in ocean racing. But yes, we're exploring. When you look at the landscape, there are structural problems on all the boats, problems of shocks with UFOs on all the boats. That didn't appear in this Vendée Globe. It's not the foils that cause shocks. The foils allow you to go faster, that's why they are fitted.
In 2016, we didn't even believe in foils. In the end, in this Vendée Globe, five out of eight of the latest generation of foilers finished the race, even if they encountered problems or had some setbacks. We're going faster, we're making progress, we're continuing to evolve, to exchange ideas and I don't think we're in a delirium, not when the main goal is to finish the Vendée Globe."
