"What could make a ship go forward if the wind's coming from the side?" "An engine" clever.

@kinga1925

3 жыл бұрын

bro where tf is all of your replies

@theflamekeeper6670

2 жыл бұрын

Lol

@mogasesegopotje8483

Жыл бұрын

​@@kinga1925looool, good question. 😂😂😂

@joemamaligmaballs7737

Жыл бұрын

let that dude think about his life 10 years ago

This is the first episode of Veritasium that I have watched where I feel like I did not really learn anything. I love the channel and this is a great subject. Lots of physics involved. I wish that you would revisit this subject in the future some time.

@idle3719

7 жыл бұрын

Ccccccccc

@prisminc158

7 жыл бұрын

Yeah me too.

@industrialdonut7681

7 жыл бұрын

Oh, he used to have a lot of shitty videos lol.

@immanuellasker4273

7 жыл бұрын

well, the base is the "Bernoulli law" that is true for any modern boat sailing with an orientation of the sails included between "close-hauled" to "broad reach", depending on the direction of the wind. In all these directions the sail, due to its shape, reacts exactly like a wing, having low pressure on the outer side and high pressure on the inner side (as Bernoulli predicted). No way that any boat can go faster than the wind!... unless the hull gets completely out of the water, like in more recent boats, thanks to particular shapes of the hull and to the introduction of foils. (this is what they missed to explain in the video). What happens, in this particular modern and marvelous boats, is that the sum of the real wind with the relative wind generates a sum of vectors that increases the pressure on the sails BUT, at the same time, modifies the angle of the wind compared with boat's direction. The boat then, in order to use this additional power, must progressively tighten the sails to adjust them to the new wind direction. As a final result, the boat keeps accelerating until it reaches the "close-hauled" orientation (about 30° compared with the direction of the relative wind) that is the limit over which the boat cannot tighten the sails anymore without loosing power (stall). Finally when the boat is running "downwind", with the wind exactly behind, the sail stops acting like a wing and becomes more similar to a sack or to a round parachute: in this position the maximum possible velocity is equal to the wind speed (not considering the resistance of water on the hull). So, contrary to the popular belief, wind in the stern is the worse solution possible for a sailing boat.

@syrrysaver2775

7 жыл бұрын

TheShoreman1 I don't disagree but, he linked to videos that explain the physics. This seems to be aimed sort of at being a landing vid for new viewers vs really adding content for those already indoctrinated

The modern sailboat is one of the purest most beautiful applications of mechanics. The video failed to describe this very well. As the wind provides a pressure gradient between both sides of the sail, the force exerted generated by the lift is somewhat parallel to the of the boats boom. Why does this not cause the boat to drift off in that direction? The center board that protrudes the bottom of the hull causes an opposite effect to take place. The force with the wind opposes the force in the water, which is stationary. The two forces can be visualized as vectors on a vector diagram. These two forces create a resultant vector, in the direction in which the boat moves, which is a single component representing the effect of all other present vectors. For those of you who know sailing, you might know now why a broad reach (135° from oncoming wind) is the fastest point of sail, not because of the wind behind generally behind the sail, but because the vectors point nearer to the direction of motion (increasing the value of the resultant) than at any other point of sail.

@hn7405

9 ай бұрын

thank you. but that leads me to a question, it seems that vector also has a degree point upward, let assume it is 20 degree, would it change the acceleration rate or how do we value that speed?

My dad was an Air Force engineer when I was a kid & he fully explained how wings work etc. When we took up sailing, I was about 12. We took a beginning sailing course to learn all the knots & rules of the road etc. Anyways, my dad had already explained wings to me & he showed me how the sails work like wings. As far as that aspect of sailing, we were way ahead of the rest of the class. I thought it was really cool because the teacher would draw a boat on the board & indicate the direction of the wind & then ask the class who knew how to set your sails. I got up every time & drew the sails in & explained how the boat moved on the point of sail. lol I was 12 & up there explaining it to a class full of adults. I thought that was really cool. Once you understand the basics, it's not really complicated but it made me feel smart & was a big boost to my confidence.

I don't find the question obvious at all. I never learned the physics of sailing in school, and I have some background in math & physics.

4:03 That was the most uninterested response I've ever heard xD

@prashanthshyamala9713

9 жыл бұрын

Unsolved Paradox Thats called EGO!

@prashanthshyamala9713

9 жыл бұрын

Unsolved Paradox Thats called EGO!

@noaha8915

8 жыл бұрын

+Prashanth Shyamala That doesn't really have much to do with ego... He simply wasn't interested in the topic, but wasn't trying to appear rude.

@prashanthshyamala9713

8 жыл бұрын

Noah A That uninterested-ness came out of his ego and for you-- its uninterested to you bcoz of your mind-makeup man. I wonder if its so uninterested why do you take interest in responding-- interesting! Anyways,

@noaha8915

8 жыл бұрын

Prashanth Shyamala What are you talking about? "I wonder if its so uninterested why do you take interest in responding-- interesting!" I never said I found it uninteresting... I said he wasn't interested. I found the thread interesting, so I contributed to it. Simple. Forgive me if I'm misunderstanding something here, but your grammar does confuse me somewhat. And I think it's wrong for you to make assumptions about him like that... It seems very judgmental of you. It doesn't necessarily come from his ego; sometimes it's hard to give enthusiastic responses when you aren't interested. At the very least, it's apparent he was trying to be polite, which suggests he doesn't have a large ego. If he did, he'd have said something more along the lines of "Yeah, whatever, I really don't care."

Very interesting and intriguing video! I love it when physics get counter-intuitive like this, yet with a little effort, you can understand what's really going on. I think you could have spent a little more time in your video explaining how it all works. The segment was a little short and quick on that point.

OK, I recognise the last vid may have been confusing. Bernoulli is fine if you don't make simplifications like 'air meets up at the trailing edge,' and 'air does not need to be deflected by its interaction with the air foil.' This is what I was trying to say. And the reason I made that vid was so there would be backup for this vid because I knew we didn't have time to go into lift in detail in this vid.

It would be nice if you remade this video, you make them much better than you used to! Big fan, I look forward to all your new videos!

I hadn't internalized the physics, but it really doesn't take long to learn how to sail a small boat. Like, a week is enough if you have a good teacher. And then for the rest of your life you curse at Nintendo for getting it wrong in The Wind Waker.

@TheUglyGnome

8 жыл бұрын

+Keiya Bachhuber You don't need a teacher. I learned by myself in one afternoon when I was something like 10 years old. All you need is a sailing dinghy and desire to understand how the things work. Of course it didn't make me a top class racing sailor ... but my passion on sailing (created in that one afternoon) helped other guys to win an olympic gold medal on sailing years later.

@jasexavier

7 жыл бұрын

I used to teach sailing at a summer camp to kids mostly 11-13 years old. They would usually be sailing within an hour, and sailing well enough to go out by themselves in small craft and get where they wanted to go within a couple of days with 90 minute classes each day. You are correct, it's not that difficult to learn the basics.

@jasexavier

7 жыл бұрын

Oh, and yeah, I really wanted to love Wind Waker, but just couldn't stand the wrongness of the sailing.

@jeremystanger1711

3 жыл бұрын

Ironically, there's a decent chance Nintendo did that intentionally to avoid confusing players. (And of course being able to travel in any direction no matter the wind direction would kind of weaken the central game mechanic, but let's not worry about that :P)

@iwillwatchyourbacknooneels7850

3 жыл бұрын

You can learn it in a day but you the more difficult part is getting ur boat ready alone bc if im not wrong sometimes camps do it for the kids but learning how and where all the cables and how to put on the sail can be difficult depending on the boat but yeah in the end when ur on the water its pretty easy u just have to tell them some safety things bc of the metal pole they might get hit in the head with

Loved your last two videos explaining lift and how sailboats operate. Always learn something new from you Derek. Love how you question people as to how things work and even when the answer is incorrect, you have this amazing way of encouraging further discussion without ever making them feel stupid. I know this formed a major part of your thesis. Well done!

Thank you! It was clear in my head but I know it was fast.

@thtkk

4 жыл бұрын

How is that comment still not liked or replied by a single person for 7 years lol i am the first one

@theshocktart

4 жыл бұрын

@@thtkk Then I am the second ^_^

@gaijingojira3601

3 жыл бұрын

@@theshocktart Then I am the third

@b5fremdet

Жыл бұрын

​@@gaijingojira3601then I am the sixth

@Hi-sg4wt

Жыл бұрын

@@gaijingojira360110 years later and I’m the 7th

Hi Derek, I think you got the last one wrong. The boat is fastest not at 45 or 90 degrees but somewhere around 135 degrees. Sailing in this direction and thanks to the position of your sails you still have a laminar flow of wind on both sides of the sail, which generates lift (which doesn't happen when sailing at 180°) and in addition more lift gets generated underneath the hull, which causes it to raise higher from under the water, grateful reducing drag on the hull. Therefore 135° would be the fastest direction to sail.

@moaerdo1357

Жыл бұрын

Derek’s idea works In a theoretical world where you have enough ballast or counter weight to overcome the lateral force on a course 90° to the wind. Some boats like the international canoe or the amac moth mk2 sail fastest around 95° to 100° relative to the wind.

I believe the fastest point of sail is a Beam Reach (~ 90' to the wind). In this direction the sails are always powered (unlike downwind). The angle of attack needs to be adjusted as you speed up. This will still be 90' to the apparent wind but pointing slightly away from the true wind.

As a sailor, I'd have to disagree with his conclusion of 90-45 degrees off the wind being the fastest point of sail, at least with most boats. The fastest most boats goes is when they're broad reaching, or about 110-160 degrees or so off the wind. I don't know the physics behind it, but I know it's enabled partially with a combination of using wave action, being able to put up large, parachute-like sails called spinnakers which can't be used sailing upwind, and the all important ability to plane, which greatly reduces drag. Also, since the centerboard is less necessary when headed in that direction, some boats allow it to be retracted, thus reducing drag even more. Some super high performance boats may act differently, but with most traditional boats, it simply isn't true. For example, a boat I typically sail on, the Melges 24, can, in let's say 20 knots of breeze, go about 6-8 knots beating upwind, but can get up to speeds of 12-15 knots while reaching back down wind with it's chute up,

@MrJeanelgato

9 жыл бұрын

thank god some actual know how!!! the reason you sail faster as you come off the wind from a fetch to the reach and finally broad reach is because of the fatt that the boat lift generated by the sail and keel starts to move from a right angle to the wind when close hauled to more in line with the direction of course as when you are broad reaching the lift angle is almost the same direction as the direction of travel. have a look at your polars on your white sails and you will see it beautifully illustrated

@edwardlittle9362

7 жыл бұрын

Depends on the boat, depends on the wind, depends--as you pointed out--on the sail plan. On a typical 10-12 knot day in San Diego my Ghost 13's optimal point of sail is just below a close reach. As the breeze freshens, the optimal point of sail works its way down. At around 18 knots, that boat flat hauls the mail on a broad reach. All that's a bit nuanced for a four-minute video intended for a mostly non-sailing audience. He could have said a boat's fastest on a broad reach and left it at that.

@Sugarsail1

6 жыл бұрын

Depends on the boat, the sails it's using AND the true wind speed. Most catamarans sail fastest on a beam reach (90 degrees) but only in light to medium winds, as the true wind speed increases, sailing lower is faster (130-135).

@Naarden4ever

5 жыл бұрын

I've done some race sailing myself as well on various sizes of boats (catamaran up to 42 feet) and I can tell you that your explanation is partly true, but it really depends on the boat, the size, the shape of the hull, the depth of the keel and the weight. The story told in the video is true for a very lightweight boat with low friction (such as a catamaran). The lift generated is easily able to lift almost all of the hull out of the water, especially when the keel is designed to create lift in the water as well (like the curved keels you see in top level catamaran racing nowadays). In extreme cases and high speeds, these boats can actually plane on their keels alone. These boats easily exceed the speed of the wind. Watch some Olympic Catamaran or Finn racing to see an example. Bigger boats can still go pretty fast upwind, but they will definitely not exceed it; the weight of the keel pulls down a lot of the hull which in order creates a lot of friction with the water, in which case hoisting a spinnaker and going downwind is definitely faster, especially if you can plane (but for big/heavy boats that requires seriously heavy wind). For the biggest boats, making a surf (which means having downwind and riding a wave) is the best way to win time. Going downwind with a spinnaker with the 35 footer I sail right now in 20 knots will take me up to maybe 9-10 knots, but when I make a surf that can jump up to 13-14 knots easily.

I have a fluid dynamics exam next week and my lecturer is a sailing fanatic and explains nearly everything to do with lift through sailing. This helped, thanks!

I've been wondering about this for a while now, ever since I found out about the center board from Top Gear. surprised I never saw this video, been subscribed for years

Usually when I watch these videos I can't believe people don't know the answers to what you're asking them, like in the "What makes a tree grow," but in this one I was just as stumped as everyone else. Learned something, thank you!

that guy actually did not explain anything at all... wtf.

@thepussygrabbingfamilyvalu557

8 жыл бұрын

+Clark Eom totally. the sail guy repeats the bernouilli stuff we all learnt in middle school. he should know better.

@RForReversal

8 жыл бұрын

+Clark Eom it made sense to me...

@monsieurbernoulli8101

8 жыл бұрын

+Carl Coppens u wat mate

@Paulo_Dirac

7 жыл бұрын

asking question is at least as valuable as answering them ;) it rises awareness

@philipfahy3589

7 жыл бұрын

Essentially a sail works as a sideways wing.

My father had me on a sailboat from an early age, and one thing i learned more than anything else is that you use the sails to push the keel against the water in different ways to create the pressure to 'go faster than the wind'. Water currents also come into play. Moving into the wind requires 'tacking' back and forth sometimes depending on the wind conditions.

Thank you for bringing in an expert, explaining the physics, and showing that your interviewees might learn something.

I burst out laughing. The engine bit starting at 1:52 was insanely funny.

DEREK!!! I love how you let people figure things out. You are the best and nicest guy EVER.

I used to be a member of a sailing club, and the mentors there actually taught us that going upwind is the fastest way to go. I always thought that didn't hold water.

Although a sail could be considered to generate lift, a simpler explanation is that similar to a wing that diverts the relative air flow (relative to the wing) downwards (when in level flight), a sail diverts the relative air flow. (relative to the sail). A sailboat takes advantage of the difference in the speed of the wind versus the speed of the water, which assuming a steady wind, is independent of the sail boat's speed. The key component of the sails diversion of flow is that it diverts a relative crosswind (relative to the sail boat) backwards, which coexists with a forwards force exerted onto the sail (which in turn exerts a forward force to the sail boat). For a given true wind speed relative to the water, then the crosswind relative to a sail boat is the sin of the angle between the path of the sail boat and the path of the true wind, and this crosswind is independent of the sailboats speed. For sailing upwind, the more efficient the sail boat, the smaller the angle between the boats path and the wind's path, and the smallest angle for a specific sail boat is called "beta". The fastest speed (with respect to the water) occurs when the sail boat travels at 90 degrees across the wind and "beta" degrees downwind. Remember the crosswind (relative to the boat) is independent of the sail boats speed and only depends on the sail boat's heading with respect to the wind. Very efficient sail boats like catamarans can "outrun" the wind, meaning their net downwind component of speed can be faster than the true wind speed. The Americas cup catamarans can achieve net downwind speed faster than 1.5 x true wind speed both downwind and upwind. Although the sail boat "outruns" the wind it's currently in, the wind ahead of the boat has a head start and the boat continues to sail into a continuous supply of crosswind, again regardless of the sail boats speed. Somewhat related, what is known as a directly downwind faster than the wind (DDWFTTW) land craft, drives a propeller with it's wheels and can go faster than the wind that propels it. In the case of the "Blackbird", it could go directly downwind about 2.5 times the speed of the true wind. en.wikipedia.org/wiki/Blackbird_(land_yacht) kzread.info/dash/bejne/Z3eXyc-pcqq5c6w.html

Your videos are excellent man, thanks for giving so often!

This is helping with my Science Fair project! THANKS! :)

super interesting... i had a guess and usually i have been close to being kinda right... this time, way off haha it's awesome to get to learn and to be so freakin off with my guesses! haha it's a cool experience.

I knew this beforehand :D But my dad sails, so he taught me when I was younger, now I know (some of) the physics behind it, thank you :)

I never understood sailing haha. This cleared it up MUCHO, THANKS!

Wow, something I've actually wondered for a very very long time now. Thanks.

3:47 is why the Olympian hesitated to answer. trying to explain it like I'm 5. the other dude still blanked out! Awesome!

I like these science related videos! Keep doing more of these Derek!

four minutes of ignorant people and 30 seconds of information. fantastic!

@krappa

10 жыл бұрын

I dont think many people know how sailboats work, no. I certainly didn't and there are even sailsmen who dont know it. So yeah, this is really interesting, even if you belong to the small minority that knows how sailboats work

@krappa

10 жыл бұрын

***** But how did you get them to be ignorant? I don't get it at all.

@Kidrock87

10 жыл бұрын

+erikharfager I guess he meant the actual definition of ignorance to be "lack of knowledge". I agree it is its true academic meaning. I believe most of us refer "ignorance" to be the noun of "to ignore", as in "disregard", which is not correct. Ignore is not the root of ignorance. I've been researched about this matter for a few, so at least I know I am correct :) Saying that, I do not condole his (stupidfacefaceface) to criticize this video to have full of ignorance. This video aims to educate, and the correct information is pretty straightforward. The point of this video is show the supply and demand of knowledge as to how sailboats work. I myself do not know how they work prior to this video and I am not embarrassed to say so. I am glad to stumble upon this video to be educated. Videos like this should be encouraged to show that people actually needs to be supplied with knowledge of various aspect. Wow, this is a long message

@Kidrock87

10 жыл бұрын

***** I think I do. He/she means "You said they are ignorant. Why?"

Wow! I was amazed how little most people know about how a sailboat works. Maybe other people want to jump in on my explanation but I explain it simply my saying that a sailboat can do more than just go downwind because it has a keel. With a keel the boat is like it is on railroad tracks and does not move sideways. The sail can be used to blow the boat down wind and obviously more and more degrees off of directly downwind because it has a keel. As the wind is 90 degrees off one side the sail can be used as a wing and make lift 90 degrees off the wing surface and move the boat forward and the keel prevents the boat from sliding sideways. Now you could see that this technique could be used to go a few degrees upwind and may a few more degrees and a few more degrees... You can keep doing this to about roughly 45 degrees into the wind. You can not go directly up wind. I hope this helps and is a very simplified explanation of how a sailboat works.

The legend of Zelda Windwaker has prepared me for this day. I used to play as a kid, and it still stuck to me today what I've learnt from that game.

Usually I would know the answers to the questions you usually ask people, and it is almost sad that most people don't know some of the answers, but you got me this time. I always wondered how sails work against the wind.

Soon, but for now it's science of sport since I'm hanging out at the Olympics with friends I grew up with who are now competing!

I enjoyed the Calculus, Geometry and Physics lecture. I have found most of the information on the internet is like getting a weather forecast. Everyone repeats what they have heard; no one verifies the facts or even knows what the facts are. Allow me to ask you a simple physics question; take two round objects the same length and size, both have the same nose cone similar to a jet aircraft. Object A; starts the gradual curve to the end (tail/stern) point at 50% of the length. Object B; starts the gradual curve to the end (tail/stern) point at 75% of the length. Simple Question: which object is faster given everything else is constant; Object A or Object B. Last question what is making Object A or B slower given everything else is the same (constant)?

please refer to the vid I did before this one "How a wing actually works". I intentionally posted in this order to hopefully make it clear. What he says is not wrong, but as you say it could be misinterpreted.

Sailing down wind is actually one of the fastest point of sail a boat can travel due to the boat will plane on the surface of the water if light enough and water current. If the hull of the boat is flat enough and is light enough it is able to surf on the waves also. Reaching or sailing perpendicular to the wind is fast but is not faster than straight downwind. Sailing perpendicular requires lots of leverage to keep the boat flat, so that the boat can travel at maximum speed on that point of sail. Many boats are equipped with spinnakers which allow the boat to travel even faster downwind. Now some boats like the AC72s and Moths are using hydrofoils which reduce friction from the water on their hulls.

Conclusion: most people don’t know, or at least are short on words to explain it. Because it is intuitive how to sail across the wind, or downwind. Tacking to go upwind is just a variation on sailing across the wind.

I am a sailor and I used similar word attempting to explain the principles of sailing to my crew. I hit a wall when it turned out most of them had no idea how wings work.

Classmates and I learned about this in Physics class, and we watched videos about the sailboats used in American Cup sailboat races.

@veritasium Here's on for you: How about other "sail like" devices - can we make one that goes directly into the wind, or can we make one that goes directly down-wind faster than the wind speed? Thinking windmills driving wheels here. It can cause quite an argument (answer is yes and yes BTW) About faster than the wind sailing - you kind of hinted at the forces involved, but it's quite simple. Terminal velocity is where all forces balance out, and that can happen at higher than wind speed if drag is low. The new AC foiling cats are doing about 3x windspeed in 15 knots in Bermuda right now, but at about 120deg off the true wind. Ice boats can do more than that, at much deeper angles again (apparent wind is quite forward at those speeds)

You can also explain the ability of a boat to move upwind using the principle of a wedge (or triangle) placing pressure on two sides of the wedge will make it move perpendicular to side 3. The two sides are A. boats sail and B. boats centre board + rudder, where the confusion occurs is that side A and B are in different locations respective to a wedge, though with the same angles they produce the same effect as a wedge. This also nicely explains how a boat can go faster than the wind.

Wow exciting info.Thanks

Think of flinging watermelon seeds by squeezing them between your fingers. Which way does the seed go? Well, the sail boat is the seed, the wind is one finger squeezing in one direction and the water against the keel is the other finger squeezing in the other direction. What direction is the sail boat going to go? That's the best way I've heard it explained.

I already was to happy because I thought he would give a better explanation than what I found through research

Hey mate, close hauled isn't actually the fastest way to sail in general on a modern boat. It's usually on a beam or broad reach (perpendicular to the wind)

I'm not sure if you'd call it sailing as such, but you can link a propellor via a gearbox to the wheels of a land yacht and go directly downwind faster than the wind, powered only by the wind. It's counter-intuitive but it's theoretically sound and has been practically demonstrated. In theory you could do the same with a boat by linking your "sail" propellor to a "drive" propellor in the water, but in practice I expect you'd have too much drag from the hull in the water.

Good video, but lacking in physical explanation. You should explain it using the ice skating analogy: the ice skater pushes his legs laterally with a force directed 60-90° to the direction of motion. The ice skates bite into the ice and transform this force into forward acceleration (that is why the ice skates need to be sharp, otherwise they would not transform this force and just slide all over the ice). That is why the centerboard and the rudder are so important: they bite into the water and propel the ship.

Wake me up when the survey is over and he actually get to the point

This is one of the first ones to actually stump me right off the bat. :p

Wow are there really so many people who have never thought about this?!

My aerospace engineer son tells me that the "convex wind speed higher leading to lower pressure" theory is incorrect. He says that no lift occurs without deflection of the airstream. A helicopter blade can spin as fast as it likes, but goes nowhere unless the blades are angled to generate downdraft. The traditional theory always bothered me as, unlike a planes wing, the concave surface of a sail is actually the same length as the convex, so the airstream velocities should be the same

sorry my friend i did not find the third link but would like to subscribe. I just saw some of your demonstrations ,obviously, and your style of them is very intriguing. I would like to subscribe to help you to make more. thanks

Oops, this is the first video where you are mistaken. I've watched about 70 of your videos so far. The sail does not act like a ridged wing structure. Instead it has more to do with fluidics where the wind is essentially redirected by "spilling" it in a common direction. The redirection of course provides the equal and opposite force which propels the boat. A parachute operates with the same principles but spillage is limited to a down vector and the decent of the parachuter is slowed.

Whit the wind is actually one of the slowest Because the sail is only pushing the boat forward instead of pulling it forward

its not about being dishonest, its about making an attempt to understand and explain a phenomena, with facts known to you at a given moment, without previously having it explained to you by someone else. it is about the one and only way to creatively inquire and push people to use their brains. I dare say this is what Derek tries to do by making these videos. With all the answers available behind the keyboard one easily forgets how to question anything. Thanks Veritasium!

The fastest position is called close hauled; it is the closest you can face toward the wind without going into irons. However if it is a rather windy day, there's a very big chance that you'll capsize.

So cool! Thanks for this :)

who’s here from the Blackbird (wind car) video?

I think I have a better explanation for that. The sail with the boat act like a peace of soap squeezed by a hand against a wall. The water plays the role of the wall and the hand that pushes the soap is like the wind. If the wind goes in a certain direction and the boat and water are at rest initially, then it may not cause movement as a whole to the opposite direction, given the conservation of linear momentum law. So, actually, the water (or the wall) is pushed in the same direction of the wind (the hand), but the boat squeezed against the water (the soap against the wall) is pushed by the water and the wind (the wall) in a transversal direction or even, to some extent, possibly against the wind. Never in the exact opposite direction, though. So, I think the answer to the main question, that is, how can the wind push a boat in its opposite direction, is “the wind is actually pushing the water, the boat is just being squeezed in the process”.

@GaudioWind

8 жыл бұрын

***** Thanks, Barney.We can also see that the boat without a keel to pressure the water can't go against the wind. Another example is the kitesurfer. He can go against the wind pressing the water with the board, but he goes always in the wind direction when he jumps off the water.

that is true for 2 sail boat, but if you do the classic raft boat with just between 2 horizontals?

Oh something I didn't really need an explanation for, now I want to go sailing though just a bit of the summer left to do it. On a side note I think every so often you need to put a video up with people who actually know the answers to your questions, just as a little behind the scenes. It would make me feel like the world isn't quite so stupid.

Soon as I heard the word 'lift' I finally understood the answer to this question I've been asking myself for a little while now

Agreed, it's not about distance. It's simply the sail diverting the air from a path it was going previously. This diversion causes some backup in the molecules of air, leading to higher pressure on the interior of the sail. The diversion towards the inside leaves a void on molecules of air (low pressure) on the outside.

Good vid. I had the same misconceptions.

Looking at the polar plots of several recreational sailboats, it seems that for most boats the maximal hull speed is achieved at a true wind angle of around 145 degrees, so diagonally from behind. The peak you described at 40 degrees due to the Bernoulli effect is only present in sport sailing vessels it seems. I guess because of the light high-performance materials reducing friction. I am not a sailer so correct me if I'm wrong.

Can you explain why air travels faster over the upper surface of a wing?

But here's another fun question, how is the sail pulling on the boat? Where is the force being transferred from the sails on the model into the boat to make it go forward?

It is probably possible by linking a wind rotor to a water rotor to get a boat to go *directly* downwind faster than the wind. The key is that the difference in speed between the water and the air is what provides the potential. Some sail boats can get to point downwind faster than a packet of wind would get there but they need to tack back and forth to do it. The mechanism is very similar to the linked propellers but it is unwound.

This was a really interesting video! Also, your beard-level is round-about perfect :)

Understood. Just felt like we were going backwards :-). Keep up the good work.

I always assumed, and was taught as a child sailing with my parents, that when you're running (nautical term for moving in the direction of the wind with full sails) it feels like you're not going very fast because the wind is behind you. There is no wind in your face, which is what people usually associate with speed. If you were to put your finger in the water, however, you'll notice that you're really moving fast. I don't quite understand the premise laid out in the video for that reason.

I always say that if you ask me question I would know the answer! I was right until now - I did not know about sails generating lift. so thank you, I learned something new.

1:52 brilliant answer, lol. awesome video, maybe the best on this channel :D

So the conclusion from this video seems to be that the fastest point of sailing is close hauled into the wind. But doesn't this depend on the boat? On its efficiency and drag? I would have thought that on some boats the fastest would be a broad reach, just off of directly downwind. On a boat with terrible efficiency, such as a square rigger, maybe the fastest would be directly downwind?

I sail every Saturday! This is Relay useful to me!

I get it, although you may have more initial acceleration with a tail wind, the acceleration decreases proportionally as velocity increases. But at a 40 degree angle, although most of the acceleration is perpendicular to the boat, the component that is parallel to the boat will more or less remain constant, and will be less affected by the velocity of the boat increasing. Pretty neat!

Many expected an explanation from Derik but the reason he didn't do that was that guy himself exlplained all and most of them was correct

I could attempt to talk about the dynamics of a sail, but the sail is just a wing and you already did that... plus I'd probably stuff it up! :) Fun stuff!!

Would this work in another frame such as the bottom of a long swimming pool that also has a current flowing? Of course the question is would a propeller Contraption like this be able to move faster than the current?

@fshihab

3 жыл бұрын

You're coming from the latest veritasium video, aren't you?

@a.y.102

3 жыл бұрын

Yes. In conclusion, as stated in Derek's most recent video, if you have 2 mediums moving relatively to each other, you can theoretically build a vehicle that go faster than the relative velocity of the 2 mediums.

someone experienced should make a circle to show how fast you can travel in any direction relative to the wind, showing how fast the boat would go and where you'd have to put the sails.

Here in 2021, wow, look at this young guy!

Actually, the fastest a sailing boat can go is with a TRUE WIND coming around 45 degrees from the stern (rear). As the boat increases it's speed, the RELATIVE WIND comes forward, further from the stern and closer to the bow, until it ends up sailing about 40 to 45 degrees from the RELATIVE WIND (which feels like sailing upwind from the boat's perspective). True wind is much lighter and it's still coming offset from the stern. The exact angles obviously depend on boat and sail design, and wind speed.

the sailing thing is counterintuitive. Lift is not as obvious as drag.

Something very weird just happened, I just saw Brady's sixty symbols video on Kelvin effect and this video came into recommendation. They are related but not obviously so, and they are years apart by different creators and don't even have nothing in the title in common. The algorithm is A LOT smarter than I thought if it can do this kind of connections.

I think it is 'easy'(theoretically, meaning infinitestimal drag for boat) to traveal faster than the wind which is driving the boat. One example would be positioning your boat perpendicular to the wind and positioning the sail to any angle below 45 degree.(The smaller angle you positioning the sail, the faster you'll be. ) Am i right?

Great Vid

I understand. Sorry about the confusion. FWIW, in ideal conditions some of the fastest more or less "conventional" sailboats can get DDW faster than the wind in "velocity made good" terms. I think Tornado cats with the spinnaker rig can just about do it and 18 foot skiffs are also on the cusp. The last America's cup boats were faster than the wind both upwind and down. All of those "tack" (jibe) downwind.

Valid point but didn't really explain it. Just some handwaving about "lift". Maybe blatantly state what was kinda said that as you sail into the wind the relative wind increases so you sail faster so the relative wind increases so ... And maybe a force diagram showing the sail putting a sideways and a forward force (when boat and sail are angled correctly into the wind) to propel the boat (or is it a ship?).

Another fast way to sail a sailboat is going on about a 85 to 70 degree angle generating low pressure on the front of the sails and high pressure on the back of the sails.

true that is the idea of what I was trying to say my point was that the center board is not pushing forwards if anything it is pushing backwards

1:47 I bet he was thinking: "Damn, this guy is going to break my boat"

Its funny how the Canadian guy gives such an elaborate explanation of how fluid dynamics works in reference to a sailboat...while he forgets that in Canada the wind just goes,"Oh, Soary" and gets out of your way so that you go wherever you want...

to my knowledge the center board doesn't actually generate any force it just prevents the boat from moving sideways because of the large mass of water it would have to move so then the boat has to move forward. I imagine it like a ball on a hill gravity is pulling the ball strait down but the ground underneath it is preventing that so it goes down at an angle.

Makes me wonder...if sailing is an example of a hydrofoil at work, what prolonged the invention of flight so many centuries after sailing? Was it the lack of propulsion/windspeed required to generate the lift required for flight? Someone should've put the sail horizontal much earlier!

@alextowers3564

2 жыл бұрын

Because when you are sailing, the wind provides the driving force, and all you have to combat is the resistive forces of the air and water on the boat. But when it comes to flight, the wind is not strong enough on its own to cause enough lift as you also have to counter the weight of the aircraft. You therefore need to induce artificial wind by pulling the wind forward through the air to make up the missing airflow that the wind was not able to supply, and the technology of the time was not advanced enough to pull the aircraft through the air fast enough to create enough lift.

Man this vid was great, genuine oooOOOOooooh moment. Oh and the guy with the cap on is dutch.