While the mini Transat is just beginning, let’s have a look at the incredible new IMOCAS that will race the Vendee Globe. This edition will be specially interesting because not only the number of new boats is big (8) but also the number of Naval Architects that designed them is considerable (4).
Unlike on the last edition, where most of the new boats were designed by Guillaume Verdier, this year he will have only two new boats racing (Apivia et aDvens) while Juan Kouyoumdjian will have also two (Arkéa-Paprec and Corum), VPLP will have three ( Charal, Hugo Boss, DMG-Mori) and Sam Manuard will have L’Occitane.
Sam Manuard is the least known and also the one with a smaller cabinet but you will remember him if I say that he was the designer of the Seascape 27 (today First 27) and more important, the designer of many recent winning boats on the class 40. He is also a good solo/duo racing sailor.
And to make things even more interesting the new boats are very different regarding design and foils. Some are designed to fly high on the water like VPLP designs, narrower boats and designed to have a minimum drag while flying, sailing with little heel.
The designs of Verdier are quite the opposite, quick to raise the bow out of the water but not designed to fly high. He bets on a superior stability given by beamier hulls that provide a big lateral support to the boat.
For diminishing wet area, their boats are designed to sail with a considerable heel. The approach of JK is an intermediate one with beamy hulls needing heel for the righting moment but with a foil design that allows the boat to go higher on the water, as we can see on spectacular images of Arkéa-Prapec.
And the surprise may well come from Sam Manuard that says his boat will be very different from the others and from Sam good things are to be expected. He does not have the same experience regarding foils but he is working with Nat Shever the one who designed the foils on the winning boat on the America’s Cup and who is working now on American Magic.
Regarding the rules of the last edition there is a change that brought a huge evolution: now it is possible to modify the angle of the foils but Michel Desjoyeaux, the double winner of the race and today involved in boat design, says that the boats will be unbalanced without foils on the rudders (that are not allowed).
The IMOCAs, in what regards foiling, have only 2 support points, keel and foil and are inherently unstable having the need to have a bit of the transom on the water for support. We can see on the Hugo Boss video that when it goes higher and lifts the transom out of the water instability follows and the boat falls backwards due to lack of support.
It seems obvious that the boats to continue to evolve need lateral foils on the rudders, but it don’t seem probable the rules to be changed before the Vendee Globe.
Regarding the performance of the new boats versus the last generation ones, Lauriot-Prévost (from VPLP) says that Charal can foil with 13Kt of wind and that, while older boats with 16Kt wind could do 22/25kt, the new ones can go at 26/30kt.
When the boat starts to foil it will win 4kt speed. This means that the angles that they will choose to sail will be different depending from boat to boat and the wind needed to foil. Everybody will be looking for conditions to foil even if that means a slight detour that will be more than covered by the extra speed.
A difference of 96 NM each 24 hours is a huge difference and certainly means that, if they don’t break, one of the new boats will win the Vendee, but it is not sure that they will not break, specially the foils.
The foils are now much bigger and the forces on them increased a lot. And if they break probably the high flyers, the boats from VPLP, will be the ones that will see their performance more compromised: they are narrower, with less righting moment and specifically designed to fly.
Maybe Guillaume Verdier and JK are counting that the chances of a boat to do the entire race without breaking a foil are slim and are not handicapping so much their boats in what regards sailing without foils.
Also big foils, like the ones of the VPLP designs, cannot be lifted on any considerable extension and therefore in light winds they make the boat slower due to more drag. Not that on the Vendee there is a lot of light wind but they will find it on the Doldrums, that they will pass twice and there a considerable difference of speed can be very important.
Foils will probably be the key element of the race. It will be a fight between more lift and more drag (flying boats) versus less lift and less drag, this in what regards the drag from the foils because the superior drag from the foil can be compensated by the smaller drag of a boat flying. Probably, if the design is equally good, foils with less drag will tend to break less than foils that offer more lift (and drag). All very complicated and interesting.
One thing is for sure, this will be a great race and one not only among sailors but also among designers, kind of race that makes yacht design progress, my kind of race.😉
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