performance

You tease! <img src=

alt=

/>

I (still) believe it is down to the skill of the sailors, and time in the boat builds skill. You build skills faster if you use the time spent on the boat to train seriouosly instead of zipping around.
This summer I had the opportunity to talk with the skipper of the norwegian tornado in the '84 L.A 'games. He said that they had bin finishing in the middle of the pack for some years, until the spent a winter sailing the boat instead of putting it in storage. Then they jumped up to be a top ten finisher consistently. Time in the boat made all the difference for them. Same time at Kielerwoche the russian team came with some old worn out beater sails, but was still the fastest boat on the water due to time in the boat.

But from time to time there is a technical improvement, like the Gran Segel spis who blitzed the fleet at the Tornado worlds in Marthas Vineyard '02. Now everybody has moved to the same shape, or even more extreme variations of the same shape.

Just wait until a Tornado shows up with Foils on it...

(Of course that's a joke)

Foils are not permitted on the T, but other platforms might see them <img src=

alt=

/>

I know Rolf, that's why I said it's a joke...Otherwise they would already have them.

Other than F16/Stealth, where might you expect to see foils?

Would you expect to see lifting foils?

The Stealth uses them on their rudders for stabilization of the platform which seems to be effective, but they don't try to lift the platform out of the water from what I can tell.

If you were to do a

clean sheet

approach to the F16, would you try to incorporate

lifting

foils?

Well, some crazy Swiss guys have done it on a 18 ft skiff, which should be harder than getting a catamaran foiling, as the cat has two hulls.. Check this link out:
http://video.google.com/videoplay?docid=-8295748797771264466&q=18ft+skiff&hl=en

If they can get a skiff flying that well imagine what could be done with a catamaran. Maybe take something like the foil system from a trifoiler and mount it on my Tiger. I think they actually weight about the same. No need for the amas Greg K just mount it to the front crossbar. Keep the daggerboards where they are so it can be used in displacement mode as well.

Later,
Dan

Uni rigged M20 took place 1, 2 at Texel. They passed the Eagle 20 on the upwind. The M20's with jib (M20 GTI) came 4, 9 place.

/håkan

My real question is,do you think lifting foils would make the boat quicker around the bouys?

Looking at that 18 Ft. Skiff video, I keep thinking that an identical boat without the lifting foils would be quicker around the bouys. They were on a close reach, probably looking to get maximum speed, but the drag of the foils made me think that even at that sailing angle, they might have been faster without the foils. In my opinion, in windward/leeward competitions, the foiler would be slower.

What Stealth do with the rudder foil looks much more promising to me and I would want to do it if

legal

within the class.

I don't think it's fair to make the 18 on this video represent foiling boats as they obviously had not worked out efficient foiling technique yet (like the guy who has to run forward to the bow every time they get foiling). Obviously foiling will decrease dramatically wetted surface, which is the biggest aspect in terms of friction forces on boats. So theoretically a foiling cat should be faster than a non foiling cat (duh:)). How much is yet to see, I will hopefully do some study on exactly this kind of stuff when I finish my Master degree in Marine Technology some five years from now:) However, foils sure made the Moths faster...

I am pretty sure lifting foils on a cat will make us even faster. And a catamaran is an ideal platform for foiling with its light weight and wide platform. There has been several tests with lifting foils on cats, and they are really fast when they get them to work. Dave Carlson (dacarls on this forum) has a webpage with lifting ladder foils in practical use.
But not everybody will think a foiling cat is still a cat, and do we really want to go in that direction? Lifting

banana

foils might be acceptable to most of us tough, and I think we will see them in common use soon.

Does this mean, Rolf, that we're about to see a semi-foiling Blade? <img src=

alt=

/>

Sorry John, there is just no time to develop them til Zandvoort. If I had time, I would have loved building and testing them. But the C-class have used them (Patient Lady 6) and other efforts are underway.

One of the things that I have wondered about while watching all of these foiling craft is the effect of foiling on windward performance. When these boats are riding along, at times nearly the entire centerboard is out of the water. That's got to just about kill all of the lateral resistance. This is evident in the 18skiff video, when they get going, the boat heels to windward and the guys come running in off the wing. I guess it's part of the technique where the skipper trys to keep the hull just above the water surface, but it seems like they might benefit from putting more board below the foil, or moving the foil up higer on the board.

sm

prototype of a single-handed hydrofoil sailing catamaran

boy that thing is OOGLY 😛

Maugan:

As cool as the TriFoiler looks now (my opinion) it was not the best looking girl in school when it was a prototype.

Later,
Dan

When you heel to windward the foil gets more vertical providing lift to windward.

And isn't this premise to increase speed by reducing the wetted surface of the leeward hull? And not fly it, which could result in nastier pitchpoles?

Which is why I posted the only foiling cat I could find. Not what I had in mind. The beach wheels and anti-pitch tabs are cool, eh? You're right Dan, it can only get better.

Yes, this is true.
However, now you've got the sail raked to windward rather then operating vertically. Plus, the portion of the centerboard that is in the water is trying to pull the boat down, counteracting the vertical lift of the foil.
I've never sailed one of these boats, but it just seems that there could be something to gain by having more board in the water and sailing the boat flat.

sm

Joddy Chapman's foiling cats:

Speed Sailing Pages, Ceres

Calliope, Ceres and Demeter Sailing Hydrofoil Catamarans

Dave Carlson:

Foilcat

why could the [retractable?]foils not be mounted on the front beam??

Been There Done That!!

This would be true if there was not any drag induced by the lifting component of the foils. But how much drag is that lifting component and what effect does that have on the whole race around the bouys? In the end, that is the real question. If it were easy, then Phill Brander's Blade F16 would have lifting foils, wouldn't it? Or maybe it will be on Blade II. F16 and C-Class and 18 Square Meter are all classes that race around-the-bouys, but none of the winners in these classes are using lifting foils from what I have seen. I think Cogito uses asymetric boards that are angled for lift, but I never saw a picture of it with both hulls lifted out of the water.

This bodes well for the development of a foiling cat!

Currently there are no plans to make a full foiling or partially foiling F16. It is still not regarded to be a winning concept over all encountered conditions.

Personally I don't believe that full foiling is the route to succes anyway. If anything partial foiling is the way to go. This means that less then 100 % of the total weight is supported by the foils. The remainder is still in bouyancy mode (displacent). However no plans are considered of this setup either. For really effective partial foiling you need to use asymmetric foils which in themselfs are not particually handy in a crowded fleet. Pretty much the luff board needs to be raised while the lee one is fully lowered. This makes

banging a tack

rather problematic.

So don't hold your breath guys.

Wouter

Classic Wouter, I love it.

Matt

I think the Formula 60s also uses asymetric foils that are angled.. Did not the White F20 also use angled foils? I think it had two sets of boards, one pair was angled. Lifting boards would be fast by making it possible to push the boat harder down hill would it not?

The ORMA60 tris definately use curved asymmetric foils in the floats to gain some vertical lift. You should know, after all a broken

banana foil

cost Knut Frostad the first place in this years Oops cup. I think Wouter is pretty spot on in his assesment. Banana foils with the aim to lift only parts of the hull clear will be the first step for competitive foiling (in my opinion).
If we look at how the Moths developed, the foilers did not win in the beginning. Then they started to dominate under certain conditions. Now you 'need' a foiler to be competitive in their worlds. It takes time to develop, but foils