Off Topic - America's Cup Sailing - Foiled Monohulls

[Hugh2]

The foiling IMOCAs are amazing, imagine trying to sleep, alone and exhausted, in the middle of the southern ocean and roaring forties while racing as fast as you possibly dare. Check out the Charal videos here, she just won their latest race yesterday.

https://www.sail-world.com/news/210446/ ... al-foiling

[Kite Runner]

These are pretty cool, but I bet the foils are computer controlled... does anyone know? If they are, then unfortunately this technology will likely never make it to mainstream boats. It's like watching a life-sized science experiment.

[Hugh2]

As far as I know, the new IMOCA 60 foils have to be adjusted manually by the sailor, and allow only 5 degrees of adjustment to rake and angle of attack.

This article indicates that the same is true for the new AC75 boats, although teams have tried various ways around this restriction.

https://www.yachtingworld.com/americas- ... ems-124434

[Dave_5280]

Nice video and article by Andy McLean from the New Zealand team:

https://www.ineosteamuk.com/en/article ... Tk_FJH2cwg

[davesails7]

These are pretty cool, but I bet the foils are computer controlled... does anyone know? If they are, then unfortunately this technology will likely never make it to mainstream boats. It's like watching a life-sized science experiment.

I don't think so. I think when they foil too high, more of the foil comes out of the water, and it drops back down. It regulates itself by how much of the foil is in the water.

[Hugh2]

These are pretty cool, but I bet the foils are computer controlled... does anyone know? If they are, then unfortunately this technology will likely never make it to mainstream boats. It's like watching a life-sized science experiment.

I don't think so. I think when they foil too high, more of the foil comes out of the water, and it drops back down. It regulates itself by how much of the foil is in the water.

Correct, Dave, that's the fundamental design feature, but the new IMOCA rules also allow slight manual adjustment of the foils by the sailor. And take a look at the monster foils on this IMOCA.

[neilhapgood]

is it intentional that the foils don't bring the boat right out the water but provide some lift?

[Hugh2]

is it intentional that the foils don't bring the boat right out the water but provide some lift?

Yes, for the sake of control. The foil both reduces the wetted surface to increase speed, and more importantly increases righting moment to allow more sail area.

Much discussion in IMOCA about the next set of rules for the next generation of boats (pretty much every 4 years for each Vendee Globe race). There is discussion of allowing T-foils on the rudders, which would allow them to fly higher and under control, plus automated foil controls to allow the same. Much will depend on experiences in this year's Vendee, which starts early November. Many are already worried that these current boats will be very hard to push near the limits for days on end in the southern ocean as the combination of rough motion and loud noise is debilitating.

[ieism]

If you enjoy the cup you should read “ The Billionaire and the Mechanic”. Awesome - true - story of the Oracle racing challenge. And the birth of foiling AC boats.

Thanks, I enjoyed reading that a lot.

[Bille]

As far as I know, the new IMOCA 60 foils have to be adjusted manually by the sailor, and allow only 5 degrees of adjustment to rake and angle of attack.

...

5-deg would be more than enough ; if they allowed a wing on the rudder.

interesting as a cat is always quicker than a mono hull without a foil, does a foil remove the advantage?

I think at that speed ; it's all about wetted aria , and the 75's are faster , because
of it ?

Bille