Little America's Cup UK 2013

Onthe2ndwire, why not pdf the book and post it here on boatdesign.net.
I did this with Light Brigade (also check out Coolmobility site) and although there's no money in it, many people get to download and enjoy (I hope) the contents. Internet community thing.
And later, if you've got 30 grand to spare, publish it yourself.

 

Lac 2013

Another very good article in the February 2014 issue of Seahorse magazine by Magnus Clarke. The following is an excerpt from the article:

"The Emirates Team New Zealand system, which is really the basis for C-Class foiling, relies upon the use of leeway to moderate the effect of the lifting foil and to help make the boat heave stable. As the boat sails down the track and begins to fly it speeds up a great deal due to reduced drag. This extra speed alows for a great deal more lift to be produced by the foils and so the boat rides higher, as the mass is constant. As the boat rides higher there is less foil in the water. If the strut is principally responsible for limiting leeway there is now less of it to do the work of keeping the boat moving forwards. The boat automatically corrects for this by yawing, at which point the strut will use a higher angle of attack caused by the leeway to create a force equivalent to the wing's side force.
The leeway, however, has an effect on the effective angle of attack that the foil wing experiences. As the boat crabs sideways the wing- or relatively horizontal- portion of the foil sees a lower effective angle of attack and as such the lift produced is moderated or reduced until the boat itself reaches dynamic equilibrium. This is also aided by the inboard tip starting to breach out of the water-this reduces available area to create lift for the boat and also leads toward dynamic stability in heave."
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Another tidbit I don't think I have previously seen is that Hydros set the new top-speed benchmark for the C-Class of 31.6kt.
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Interesting that the Hydros foils were designed to be able to be inverted (and apparently, switched side to side) for light air when a lot of vertical lift wasn't needed.

 

C Class

Production C Class? http://perspective-design.com/EN_C-Class_catamaran_innovative.html#