Foil Assist Monohulls

This was posted in the "Route du Rhum-monohulls" thread and seems to be a great result for the viability of "foil assist". One needs to substitute the words "foil assist" for the word "foiler" below for a proper understanding of the meaning technically. The word "foiler" is used by some writers to describe boats that aren't actually foiling:

Summing up the Azimut Challenge:
VALIDATE THE TECHNICAL CHOICES
More generally, the challenge Azimut was used to test and compare the different types of foils, to make a technical assessment of the innovations of the moment. Antoine Mermod: «I think we have definitely buried the debate between foilers and non foilers. The Challenge confirmed that foils are the answer. From now on, we enter a new debate between small foils and large foils. We have seen that PRB, with its large appendages, has interesting attitudes at all speeds. The choices made by Vincent Riou and his team seem very positive. "

 

Foil Assist---Charal: big air!
pictures from catsailingnews by Yvan Zedda:

 

Charal-2nd best video-see post59 on the previous page for the best :
Video of the amazing IMOCA 60 Charal foiling https://www.sail-world.com/news/210446/Video-of-the-amazing-IMOCA-60-Charal-foiling

 

Video of the new Code 1 Foiler de Black Pepper yacht, Naval architect Marc Lombard :

 

That's an ugly boat. No interior shots to show how much cabin space is lost to the centreboard and foil cases plus associated tackle. It's got twin hexagonal wheels though, very ergonomic. ;-)

 

Interview with Vincent(found in"FOILERS!" by Fred Monsennec)--
Interview Vincent Lauriot-Prévost: "The foil, I think we can not do without it"

Vincent Lauriot-Prévost : 'Le foil, je crois que l'on ne peut plus s'en passer' https://www.bateaux.com/article/29046/vincent-lauriot-prevost-foil-crois-l-on-ne-plus-s-passer?utm_source=Tip+%26+Shaft&utm_campaign=bf5a4f9421-EMAIL_CAMPAIGN_2018_09_25_03_05&utm_medium=email&utm_term=0_af455e7661-bf5a4f9421-95532093

 

Very interesting article, thanks.
Within the evaluation of the foil effect that I did for the Figaro 3 case, I showed that there are 3 steps in the foil assistance :
- in light winds, the lift/drag ratio (.i.e the finesse) of the foil is a lot lower than the one of the boat (where lift = buoyancy) : the extra RM created by the foil is very small and moreover does not compensate the extra drag of the foil.
- in moderate winds, the lift/drag ratio of the foil is still lower than the one of the boat but in the same order of magnitude (let'say no less than 0,5 times the boat one), and then the extra RM created can give a bit more speed as long as that overcomes the extra drag of the foil. So one positive effect (more RM) which can counterbalance a negative one ( more drag).
- in strong winds, the lift/drag ratio of the foil finally becomes higher than the one of the remaining buoyancy of the boat (especially when Froude is in the 0,4 to 0,7 range) and then we have a double positive effect : a large fraction of the boat weight is supported by a device (the foil) with less drag, and an important extra RM is created ( + a small but non negligeable effect : the heeling arm is slightly reduced as the drift resistance from the foil is at the water surface level) : then we can have a significant extra boat speed.

 

Vincent Lauriot-Prevost from the article:
"Today, especially when talking about a Vendée Globe boat, you have to respect tonnage rules. They are binding compared to the foils because we are not allowed to add carrying planes on the rudders, which would allow to balance and to plan the boat completely. If we could rely on other buoyant plans, it would allow us to fly even more. But today, as the gauge forbids, we will try to adapt in this direction. Unless it evolves " (Bold by dl)

 

https://www.balticyachts.fi/supercharged-foil-assisted-baltic-142-canova-on-course-for-spring-launch/

 

About Imoca foiler Charal, this interview of Jeremy Beyou, after the RdR and intense sailing in december, they are analysing all the performance data and thinking about a second generation of foils (they already secured the budget for). DecisiOn by end of january. And Jeremy Beyou also dreams to participate one year to the Sydney Hobart with Charal …..
https://voilesetvoiliers.ouest-fran...ie-beyou-eff2b402-0e9f-11e9-8440-3c78224f6cd6

 

Thanks! Here is another article speculating on foils in the Sydney-Hobart: Sydney-Hobart-2018 https://www.boatdesign.net/threads/sydney-hobart-2018.61542/page-3#post-845810
post 42. That will be so great and add a whole new dimension to the SH!

 

Club Swan 36---very cool!!
ClubSwan 36 https://www.clubswan36.com/



See post below for the first published version of a single curved lifting foil!

 

Whadyaknowaboutthat!

Single Curved Lifting Foil by dl 3/17/2011:

 

Cool presentation but I am a bit intrigued by this approach : the lateral resistance (with a bit lower heeling arm when compared with the one with a keel wing) seems the main goal with this circular foil acting as a twin daggerboard, the lift part seems marginal.

 

So why do you think foilers aren't allowed in the Hobart now?