Physics of Sailing Video 2: Drive in Sails 

I’ve been trying to find these exact videos for a week now. I can’t believe it took this much time since I was searching the terms “physics” and “basics of sailing”. Anyway, they’re perfect, and I understand exponentially more now that I’ve watched a few of them. I don’t have PayPal, but I could use Zelle! Thank you!

I think that Bernoulli effect plays a significant role especially when the sail is well trimmed. And the carbon based foils are specially designed to harness the Bernoulli effect in particular.

Terima kasih informasinya dan arahan yg sangat bermanfaat untuk belajar.

Awesome video, thanks! However; a curved airfoil DO create a low pressure (suction/lift) on the curved side as well. Just hold the curved side of a spoon under running water from a faucet, and you’ll see. Better yet, next time hold that piece of paper stretched out in front of your mouth and blow on top of it. Same result.

Owen, thank you. I too was skeptical about the Bernoulli principle on a sail (or on a flat hand held at an angle out the window); intuitively and physically it didn't feel right. I'm going with your explanation re vector forces. thanks!

Ty

Think I'll go with the NASA engineer. You gave a good explanation of a boat which moves sideways. And a sail is not flat when full of air it looks remarkably like a wing shape when full of air.

Fascinating videos thank you. This leads me to ponder the role of the keel ?If the wind vector pushes the boat sideways how does the boat move forwards?

One question. This doesn't explain how the drive force in sails equates to a forward motion. The drive force is mostly oriented sideways, not along the longitudinal axis of the boat. So while there IS a forward component, it is usually not the major component. How does the shape of the boat, and the implementation of a keel factor in to make your boat go forward, instead of sideways? In aviation, a similar phenomenon takes place, the reaction force isn't oriented perfectly perpendicular to the wing, it is also oriented back. This is induced drag, drag created because of the production of lift. What is that sailing equivalent?

Granted, you are trying to simplify here, but the incidence angle is the angle of the wing to the aircraft. The angle of attack is the angle to the apparent wind. So, for example, an aircraft with an incidence of two degrees must be pitched up 8 degrees to achieve an angle of attack of 10 degrees. Lift is perpendicular to the angle of attack, by definition.

owen, thank you for clearly explaining angle of attack and newtons principles as the main lift component of a sail. it is disappointing to see and hear 90% of both sailors and pilots consider Bernoulli's principle to be the "main" lift component.