twice as fast as windspeed: Can an America's Cup Yacht be too fast?

[cali]

A death of a British Olympic gold medalist during an America's Cup sailing practice on Thursday have prompted new concerns about the high-speed catamaran that capsized in the San Francisco Bay.
Andrew "Bart" Simpson was part of an 11-man crew aboard Artemis Racing's AC72 vessel when the boat flipped northwest of Treasure Island about 1 p.m., officials said. Simpson, 36, served as the Swedish team's strategist.

An America's Cup chase boat pulled the sailors from the water, but Simpson was trapped under the 72-foot catamaran for up to 15 minutes before he was reached, San Francisco Fire Department spokeswoman Mindy Talmadge said.

The incident comes about seven months after a similar yacht owned by the Oracle USA team capsized in October, also while training in San Francisco Bay. No injuries were reported, but the vessel was damaged.

The AC72 is capable of speeds in excess of twice the windspeed.

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http://www.latimes.com/local/lanow/la-me-ln-americas-cup-safety-20130510,0,4231149.story

[cherokeeprogressive]

1. Nnnnnnope

[Junkdrawer]

2. 2x windspeed? is that done using the sail's airfoil effect?

[Brother Buzz]

4. They are achieving these speeds because the boats are so light

that, and reduced wet hull drag. Windsurfers can go faster, but they cant their mast INTO the wind and produce lift, further reducing drag.

[ladjf]

5. Yes.

[Junkdrawer]

6. Guess it would have to. If the wind just Pushed the boat....

then windspeed would be an unobtainable top limit.

But if the wind Pulls and Pushes, well, that's a horse of a different color.

[ladjf]

7. Check out this article explaining the resultant forces of the wind on a sail boat.

http://www.marinetechs.com/Theory-of-sailing

[ladjf]

8. Check out this article about resultant forces on sailboat.

http://www.marinetechs.com/Theory-of-sailing

[muriel_volestrangler]

9. While there is an aerofoil effect, it doesn't have to be as complicated as that

Most boats are fastest on a 'reach', ie when the wind is roughly at right angles to the direction of travel. So when the boat accelerates, the main effect is to change the direction the wind is apparently coming from, rather than the relative speed. And with the sail at an angle, a force from the side causes the boat to be forced forward (the keel and shape of the hull stops it going simply sideways, of course).

[L0oniX]

3. Awesome craft. I crew on a 30 phrf spin A.