Sailing efficiency: % or multiple of windspeed

Well , the subject was broached in an earlier post where there was mentioned a Moth doing 19kts in 10-12kts of wind and somebody else mentioned Nicorette doing 13kts in a 6kt wind.
I was told about the Moth by one of the guys that did it-it as the first sail of a new boat with new foils-not tuned up; I don't know the story on Nicorette(but would like to).
I know that Moths have the capability on foils to exceed 2 times windspeed as can some other hydrofoils . In fact, my 56"LOA X 72"Beam RC foiler was clocked at 12.5mph in a 5-6mph wind measured with a Davis windmeter on its very first sail with no tuning whatsoever.
So I'm intereseted in anybody elses experiences with windspeed and above sailing on the water...

[DSmith]

Bethwaite claims that the 49er does up to 2 times windspeed with the kite up.

Interesting. Simon Payne in an article last year estimated that the foiler Moth was 15% faster than a 49er.....
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I wonder about an Aussie 18?

[jehardiman]

Rember that absolute speed in relation to the wind speed is one thing, VMG to weather is another. For absolute speed,Yellow Pages Endeavour (a tripod foiler) did 46.52 in 18-20.

This web site claims 44 in 15 with a similar tripod.

http://www.macquarie.com.au/speedsailing/updates.htm

[usa2]

Nicorette was doing 13 knots while reaching up the Derwent under an asymmetrical and main. The windspeed at the time was 6 knots true. Im pretty sure that most of the large canting keel boats have done twice the windspeed before. I doubt any of them are capable of doing twice the windspeed or more when the wind is in the high teens, as Yellow Pages Endeavour did.

It was mentioned under another topic that a noted skiff rig designer said putting sail area up high paid bigger dividends than using area down low to create an endplate effect. I wonder if it has more to do with the nature of a skiff than with aerodynamics? Skiffs used to represent the pinnacle of high performance monohulls and in some cases still do but with the foiling revolution I'm not sure that will remain the case.
After all, the "lowly" 11'(12.75'LOA) Moth is already faster than most monohulls and cats under 20' with a few exceptions.
Simon Payne ,a Moth sailor from the UK, said in an article last year that a foiler Moth was 15% faster than a 49er.
Do you realize what that means? The Moth is a small boat with an approximate 220lb.'s sailing weight with 85 sq. ft. of SA . The 49er is a 16' skiff with an approximate 588lbs sailing weight and a whopping 600+ square feet of sail! And even with all that sail and all that RM( two wires) the little Moth is faster!
If Payne's(and others) observations are accurate that tells me that one 16' skiff has already been eclipsed by a new much more efficient form of sailing that does not require HUGE amounts of sail to go extraordinarily fast.Will the revolution continue with larger two person foilers ending the technical and speed dominance by 18' skiffs in the monohull world as well as surpassing "normal"(non foiled) multihulls?
I'll bet that's exactly what will happen.....

[usa2]

why would you go bigger though? The moth is capable of astonishing performance for an 11' foot boat already, and with more work on the foil design and techniques of sailing, it will pretty soon be faster than probably everything but certain multihulls.

Well, I guess one reason to go bigger would be to take care of "certain multihulls" ! But bigger isn't necessarily going to be better if foils are stuck on an already existing,unmodified, dinghy; it will probably have to be a boat designed from scratch as a foiler with a high speed rig. Further, the new boat will have to be raced intensively to develop the techniques required to get the most out of a two person foiler.
And a two person boat would allow you to share the experience...