Translator from GOOGLE

Wing sails aka Power Foil Sails = Powerful Sails ??

The very first time i heard about these sails and became interested was around June 2004 when i read an article in the now defunct American Windsurfing Magazine on page 80 entitled "Windsurfing's Nostradamus?" The article was about an innovator named George Greenough. In 1984 apparently he was already using skinny masts, wide boards for early planing and carbon booms. It seems he always was and still is a "surfer at heart" - was in California  - still down in Australia - ??

In that Windsurfing Magazine article there was also a mention of the "double surface sail with unique interlocking battens". Now this I had NEVER seen nor heard of before. I expected this innovation to eventually become a reality, but i had NOT anticipated that it would take over 15 years !!!
George was using this sail around 1990 - as per article... and enclosed photo:


Dan Kasler originally of Gaastra sails has already dabbled in the idea. This seems to have been around 2004. There were inflatable chambers that were aligned horizontally inside the sail. Never went into production.

In the race sailboats these are more solid structures:

I choose that video because they are using a SOFT sail and the narrative is a GOOD description...

Kites have been using tubes for some time and here is a video showing the power AND de-power

With all this activity in this innovation - why has this NOT gone into production ?? Here are some discussions... The obvious factors seem to be weight and cost. There is an element of transportability as well. How convenient or inconvenient is it to transport and rig ??

Now it seems a Russian innovator in N.E. USA is getting ready to go in production !!! What one can see in the photo below is 1) he has a dog :-) and 2) the tubes are going the other way - vertical to the water. In this forum discussion he discusses some issues that were overcome and how confident he is that this is going to be the sail / foil to beat !!!

As Geritt mentions in the comments, there is a lengthy discussion on the Dutch forum as well, If you clique the link, it will b translated:

There are other interesting photos as well:
"Although this sail was easy to rig, properly rotated, easy to trim it became nothing" <-- translation

Windsurfing has many aeronautic influences - example: James Drake. Foils seem to be a prevalent thought - from aviation. Sometimes tiny innovations on previous accepted concepts goes a LONG way. Now that the loose leech has been around for many years, it is becoming difficult to find a longboard sail with a traditional tight leech in North America !! Foot straps revolutionized wave sailing, bump n jump, free style, etc. How did people ever sail without a harness ? Perhaps the air bladder is only needed in a wide luff sail ?? This would save me from breaking my back when i try to uphaul a race sail :-) Maybe I should shove a noodle up the wide luff ?? :-)
In any case , these ideas like wing sails/power foils have been around and previously attempted.
Let's wish this fellow lots of luck and hope one day we will all benefit !!!!

Well, now there is more action on this front in 2017. MW wing sails seem to be available from New Jersey and are being discussed on the windsurf forums:

Here is the rigging video:

People are happy about the innovation of MW sails, but are saying what is missing is the PR and marketing. Need more comparisons and buy-in from windsurf professionals. Videos on the water are not that great either. Will post one just the same ...

For me, the largest sail @ 5.8 m² seems a bit small. In the above video she is using a 4.5 m² MW windwing sail in about 17 knots of wind. I probably weigh twice as much as her and usually use an 8,5 sail in those wind ranges. What would I use in the windwing format ? surely MORE than 5.8 !!
MW sails are saying 225 pound customer can plane in 19 mph winds with the 5.8. That's ONLY 16.5 knots !! time will tell - waiting for more data ... but am not a skeptic ...


  1. “Faced with the choice between changing one’s mind and proving that there is no need to do so, almost everyone gets busy on the proof.”

    I have been working AND sailing asymetrical windsurf sails for 20years now , no intr. what so ever....

    1. "if it works, why change it" seems applicable as well

    2. Did you see the Dutch forum ? You are free to use the pic's ont Aussy forum , I don't write English well so you can do the talking



  3. I would like to ad

  4. Well, Gerrit, I changed my mind. I used to believe that wingsails were inherently more efficient - then I read what people like Boeing wing designers, America's Cup wing designers, MIT aerodynamics professors and world record holding human powered vehicle designers say.

    They say things like "aerodynamic tests and calculations invariably show that for any given design point, a thinner airfoil will outperform a thick one"; "a thick section will generally have more drag and less maximum lift than a thin section"....."The ideal shape for high lift would be a thin, highly cambered airfoil" "Thin airfoils are capable of the highest CL and CL/CD values"...."The notion that because aircraft wings are very efficient and have thick sections, while sails have thin sections and generally lower lift/drag ratios, and therefore a thick sectioned sail will aerodynamically superior to a sail rig with a thin section simply because it is thick, is a mistaken idea. Airplanes have thick sections because they are structurally stronger and because they have to operate efficiently at low lift coefficients in cruise. This is generally not the case for most sailing craft".

    So when I read that sort of stuff coming from experts on wingsail design, I changed my mind. The funny thing is that many wingsail fans refuse to change their own mind even when they read what these designers of world-beating aerofoils and world-beating sails say.

    It's not even as if the wingsail concept is new. They were first created in about 1955. A friend of mine had one in about 1972, so it's not true that people are against them because they are a new concept. It's just that they don't normally perform as well as some of their fans say, or as well as thin sails.

    1. Chris Thompson! Than, how come all speed records on land and water done with wing?


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