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Comment by WalterBright | Hacker News Reader

Take a drafting triangle that has 30-60-90 degree corners. Place it between two objects, and squeeze the triangle between them. It'll move to the side faster than the two objects move together.

Or you can just think of it like squirting toothpaste.

The wind pressure on the sail and the water pressure on the keel form the two "objects" being pushed together and the sailboat "squirts" out the side.

Edit: The angle between the sail and the keel is like the angle on the triangle. The keel really was a great invention.

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It's like our brains aren't meant to handle resolving that not only is it pushed through, it's sucked into a thin and ever moving void. It's pushed and pulled at the same time, in otherwords, part of the continuum.

Suction isn't a real thing, though. It's just our description of when lower pressure on one side of a thing allows the thing to be moved by the higher pressure on the other side.

The pressure that the air above the wing applies to the top of the wing is lower than the pressure that the air below the wing applies to the bottom of the wing. The net force is upwards.

I'm not sure it's that simple, and my physics knowledge isn't so strong but if it's a gradient, the force of the push can't exist without being the same thing as the force of the pull. They seem to be one in the same, the force isn't onna particular side, it's the effect of the delta between points on the gradient.

That's exactly how I mentally model it. You have to imagine it like a stone skimming the surface of the fluid on one side, and a bubble "sucking" the other side into it.

It's two concurrent visualizations of the same force.

Kind of like when your car splashes into a puddle and somehow some of the water drops make it onto your windshield.

It's like our brains aren't meant to handle resolving that not only is it pushed through, it's sucked into a thin and ever moving but thin void. It's pushed and pulled at the same time.

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