open 20 footer

I don't think it's a critical problem just an interesting one. I don't thnk there is any question that foilers change the definition of sailing length.
The M4 and Wardi's Moth have a longer foil footprint then the Ilett Moth but apparently the one thing they all have in common is that they sail on the rudder foil. Now ,if it is actually sailing on the rudder foil how can you exclude that from "sailing length"?
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I assumed when I said: "actually sailing on the rudder foil" that others would know that means in addition to the main foil! Sorry for the assumption....

[usa2]

then you would use the rudder foils length as the sailing length

I don't see it as a critical problem just an interesting one. In my opinion, foils change everything including traditional definitions of sailing length; how can you not include a rudder foil that the boat is actually sailing on(transom clear of the water) in "sailing length"?

[usa2]

if you than say that the sailing length is what the boat is foiling on, you use that length. But then the moth isnt technically 11 feet or 12.75 feet as you say. What if someone made a rule that made the foils be within the effective sailing length? In other words, the foils would directly underneath the boat,

It seems to me that if it is agreed that foilers change the definition of sailing length then the most practical modern definition for foiler "sailing length" would be length overall since the hull is used in lite air and foils in heavier air. When on foils the rudder foil must be included in sailing length I would think.
The foil footprint has relevence only when the boat is flying as a measure of the boats' pitch stability.
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2 , if you haven't already look at Mr. K's boat dimensions under "Canting Keel Design"-very interesting......

[NiklasL]

As USA2 wrote on post #29 that :
"that foils will soon be suitable for open ocean racers, i dont think that is true."

There are currently at least 2 trifoilers:
L'Hydroptère http://www.hydroptere.com/

[NiklasL]

60ft This craft was designed with longer transatlantic ventures in mind

...and
Scat 37ft http://www.constellationyachts.com/scat.htm

Not as big but an advance toward bigger dsign.

The hobie trifoiler is also beeing built in a bigger version (not for ocean I think).

[NiklasL]

Hydroptere recently crossed the english channel and made a new record, thats what I call outside of a bay.

[Paul B]

Originally Posted by NiklasL

As USA2 wrote on post #29 that :
"that foils will soon be suitable for open ocean racers, i dont think that is true."

There are currently at least 2 trifoilers:
L'Hydroptère http://www.hydroptere.com/

I believe USA2 was commenting on the idea of monohull open ocean racers on foils like a Moth.

It seems Hydroptere has been proving the difficulty of foiling on the open ocean, even with a more stable platform than the Moth type. I think that boat is broken more often than sailing. Over the many years of her development, how many major Ocean Races has she won, and how many Open Ocean Speed Records does she hold?

[usa2]

yes, i was commenting on monohull ocean racer foilers. I have read about Hydroptere, and that is a much more stable platform for foiling than any monohull possibly could provide. But, if foiling really was suitable for open ocean racing, one would think that Hydroptere would be smashing records everywhere. It hasnt, and wont. If you go to google, and type in Hydroptere, the second page you get says that its optimum conditions are constant windspeed, flat water. Nothing unreasonable there. Further down the google results page is something about the second accident for the trifoiler. That page proceeds to tell how one of the foils broke off in a TWO meter swell.When we were earlier discussing the possiblity of a monohull foiler in the Sydney Hobart race, we were envisioning seas of at least 6 meters. If a foiler breaks in a 2 meter swell, something is apparently very screwed up. ANY boat designed to open ocean race has to be able to handle waves considerably larger than a 2 meter swell.

The failures of Hydroptere have about as much relevance to the succes or failure of foilers at sea as did the Comet to the future of jet travel.
Experimental boats doing what no boat has done before are bound to break-thats part of development.
Hydroptere's recent English channel record was fantastic with more to come ,I hope.
There is no way in hell that a canting keel monofoiler will approach what is possible for a large multifoiler but both boats will eventually have the engineering required understood well enough to produce reliable structures-without doubt!
But the biggest problem for foilers- mono or multi- is whats in the sea not structural engineering because once the engineering is understood there will still be containers floating just beneath the surface and that is just disaster for a foiler. So technology will also have to come up with realistic solutions to finding and avoiding the crap floating out there because safety at high speeds demands it. And they will!
There is nothing sailing on the water as potentially fast as a multifoiler(yet-except maybe some form of planing hulls and foils) and I'm sure that the problems associated with this kind of speed will be addressed and solved-thanks to people like the Hydroptere Team, Dr. Bradfield and Skat, the Aussie's with Spitfire and people like Yves Parlier that aren't afraid to test new ideas.

[usa2]

what about big waves, as i wondered earlier? You cant do anything about them affecting foilers.

2, as I answered earlier in regard to canting keel monofoilers, retracting the foils can be made to work on a multi designed for it-that eliminates the foils in non foiling conditions for speed in light air and safety in heavy.
In fact the banana board foils on Open 60's retract now for exactly those reasons....

[gybeset]

Not on a mono 3 reasons. the ballast requirements,the lack of speed to lift it and narrow footprint take it out of hydroptere's advantage area.

One more time: a canting keel monofoiler is likely to work well especially if the foils are used off the wind. In addition, a flap on the canting keel strut can be used to develop RM reducing the required ballast even more. The main foil could retract into the hull in non foiling conditions.
Still plenty of problems but probably doable in the not too distant future....