Sailing Faster Than The Wind - How Is That Even Possible?

It's possible to sail a yacht faster than the wind that powers it! Although it happens all the time, it's really counterintuitive. Can it be explained with Bernoulli or Newton? Or both?

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[SteveMould]

The alternative explanation goes something like this (I'm simplifying!) - Lift is generated when air is moving relative the sail. As the boat speeds up, the relative speed of the air should increase and so the lift should increase! This explanation doesn't work for when you're sailing somewhat with the wind though. In that scenario, as the boat begins to speed up, the relative speed of the wind actually goes down.

[veritasium]

Delighted that I can wave my hands and a Steve Mould video appears

[RealEngineering]

Not sure if I missed this in the video, but need to also consider that Derek was using a wind turbine as a sail. A turbine can act like a flywheel, storing energy. A good question to ask is “what happens when the wind stops?”. A sail boat will no longer generate lift, but the inertia of the boat will keep it going. A wind turbine however will continue rotating and continue providing lift, so it’s possible to build more speed thanks to the energy storage element. At least, that’s my assumption, haven’t thought all that hard about it.

[pukpukkrolik]

Just as an aside, in practice sailors can rely on tactile and visual feedback to "feel" their way to approximately optimal angles. It quickly becomes largely intuitive, like learning to riding a bike.

Forms of this feedback include the relative direction of small weather vanes, boat tilt or the sail floppiness.

[robotjarvis]

"Let's assume it worked perfectly"
- Oh, yes, physics

[Hephera]

7:08 this is why in sailing, changing the angle of the sail is similar to changing to a higher gear in a car. you start at a steep angle because that gives the most perpendicular force, but after accellerating for a bit you reach the maximum speed for that angle and have to pull the sail into a shallower angle to get any more speed. until you reach the maximum speed the boat is capable of when the sail is almost perpendicular to the wind.

so the best angle for the sail depends on where the boat is pointing, where the wind is coming from, the speed of the wind AND the speed of the boat.

[PlasmaChannel]

Solid collaboration. Funny that I sign up for a sailing class this summer, and boom, Steve Mould makes a video about sailing. The universe is calling mate.

[AndrewNajash]

I feel like that’s not the only framed photo of Steve he owns

[OHPerry]

For anyone wondering, there is also the really fun phenomenon of generating your own wind. Which occurs because as you gain speed, you are now experiencing wind equal to your speed(essentially) in the opposite direction of your travel. So as you speed up, you start having more wind, in a more bow(front of boat) position. So you can then capitalize on that and go faster, which is why many sailboats nowadays are optimized for more upwind sailing. The most dramatic example I have seen was America's Cup World series boats(which has all sorts of optimizations like wings and foils) and traveling downwind, they had their sails in close as if they were going upwind, and their windex's read that the wind was about 4x faster than we experienced elsewhere. Really good video, thank you for making. I did not know about the whole missing thing with the wind, and you could certainly make a hundred videos about the physics of sailing.

[thezach]

Very nice explanation, I’ve done a couple years of sailing and this is pretty accurate. Only thing is for the perpendicular trajectory, on a sailboat when you go perpendicular you will bring your sail near completely in and counter balance your boat with your own weight on a small boat like a laser.

[QuantumHistorian]

I don't say this lightly, but this might be my favourite video of yours. Something complicated and counter-intuitive explained with such elegance and ease that I'm half convinced that its entirely obvious and I always knew it. Worthy of being the first one after the million barrier

[TheHookUp]

Friggin awesome explanation and congrats on 1 million subscribers! I can tell which parts you filmed before and after lunch from the stain on your shirt :P

[Nighthawkinlight]

Bernoulli's Principle and the Coanda Effect are two sides of the same coin as I understand it. The Coanda Effect describes how flow clings to a convex surface resulting in a change in the flow's direction of travel, and Bernoulli's Principle describes how the force required to change that direction of travel is reacted against the curved surface via a change in pressure. You don't get one without the other.

[Brahmdagh]

Me: "Why do you even own a framed picture of Steve, Matt?"
*Looks at the picture"
Also me: "Holy shit, that is one handsome Steve"

[Chris-klbi]

4:27 The blue/sideways force does have an affect! Because it and the ‚resisting force on the hull‘ are offset, the boat gets tilted. Thats why big boats have weights in the keel and small boats relie on the bodyweight of the sailors to counteract it.

[vennic]

Actually, the boat moves away from Steve Mould due to the awkward encounter they had at the Christmas party last year.

[WileHeCoyote]

I love watching 3 or 4 of my favorite Youtubers all give their "take" on a physics project/thought experiment. I learn something new from each

[HECKproductions]

someone: how do you know all this?

me: i watched a man push a toy boat with wheels with a stick that also has a wheel

[gutobernardo]

Matt's been on YouTube for so long, done so many things, and I can't believe his channel doesn't have 1 million subscribers 🤔 that's the definition of underrated

[randomutubr]

Your graphics actually are very good. No need for a bunch of visual noise for gratuitous reasons. Simple shapes to explain the concept in a simple manner is exactly what is called for in a video like this. Good job.