Hi Axel,

there is a nice flash movie explaining this on www.bmw-yachtsport.com,
look for "Physik des Segelns". It's in german but I think that's no
problem for you :-)

Have a nice weekend,

Joachim

Axel Boldt schrieb:

Hi,

I'm trying to understand how a boat can sail against the wind.
Explanations on the internet usually go like this: "The sail has an
airfoil shape, the air goes faster on one side than on the other,
creating lift by Bernouilli's principle." But I know that for flying
planes, the wing's airfoil shape is not essential (otherwise planes
couldn't fly on their back): it's the angle of attack that matters. So
I'm wondering if the same is true for sailing: would it be possible to
sail against the wind with a sail that's a rigid flat surface, not an
airfoil-shaped piece of cloth?

Thanks,
Axel