An Introduction to the Physics of Sailing

[@claudiachagui8363]

Great video! As a novice sailor and a person who HAS to understand how things work in order to remember them, this video is perfect. Thank You!

[@alexf7414]

Exactly what I was searching for. Thanks

[@trackie1957]

My brother learned to sail on the other side of the river with Community Boating in Boston. The Charles basin is notoriously tricky with its shifty winds! Those Tech Dinghy boats sure look faster than the Cape Cod Mercury ones on the Boston side. Thanks for the explanation!

[@bekisellick2296]

Great lesson for aspiring engineers and sailors. Will recommend, thanks!

[@01dumbfrog]

This would have been very helpful information to have watched before I tried and failed after buying my first sailboat up in New Jersey, but we live and learn. Keep up the good work thanks.

[@MidMo4020]

I just made a sail for my kayak.. I live in Missouri. The only members of my family who’ve sailed were my grandpas to go fight the Japanese. I did use decent research and I’m reasonably intelligent but this video is just further learning on the mechanics of it. I’ve taken her out on a nearby lake a few times with modest success.. BUT I’ve definitely had some butt puckering moments! I made it Viking style as a kayak has no keel.. I sincerely hope your lesson isn’t at the bottom of whatever waterway you undertook 🙏🏻

[@marklewis7306]

Nicely explained, but perhaps there was too much emphasis on the lift from wind blowing over the profile shape of the sail in exercise 1. Those lift forces would be very minor compared to the force from the wind directly on the sail surface and countered by the daggerboard, keel and rudder. This is evident through camber-free sails as can be seen in some windsurfers and in the example where you tried to sail without the daggerboard. I am bringing this up as some people believe that the force which allows one to sail upwind is primarily from the profile shape of the sail...which is incorrect.

[@botskhasison597]

Thank you so much. As a pilot it was very interesting and enlightening to learn about the principles of the airfoil being applied to sailing. This will go far in my sailing interest. Have a nice day.

Interesting how airfoils have been on boats for millennia, but as airplane wings, not so long.

[@isnotavailable2]

The paper / fan demo is an excellent refutation of the idea that it is differential speed, caused by the curvature of the wing / sail, that creates the upward lift - not the difference in travel distance. Flat wing balsa wood gliders, launched with force by the same kids that hold their hands out of car windows, completes the idea that it's the force and the angle, more than a differential gradient, that affects the climb. One other note: air, being a fluid like any other, has a stickiness that needs to be taken into account. Hint: it's the same as the last drop of honey that climbs back up the string of honey to rejoin the spoon or the honey jar. It's a major force behind the lift you experience with wings and sails.

[@grokscience8673]

What fun! I'm thinking about an autonomous RC Sailboat. Fascinating problem! Great guns btw, result of hauling in sheets. Feed the Geek!

[@markcampbell7577]

Lateral resistance ahead of the sail effort is essential. Mast and stem lateral resistance is essential to rudder control and lift.

[@DrBroncanuus]

congratulations on this fascinating video on revealing the Black Arts of sailing........trouble is I've never been on a sail boat...but i still want to learn how to sail...

[@robertobooher8176]

Thank you 😀 Emma for that videos and illustration with diagram it made it easier for me to understand about sail. 👍👍 it was much more then i anticipated about sailing.

[@J3zzaG]

Great video! Although I think you have the direction of the “keel force” acting the wrong way at 9:53. The keel acts with a similar magnitude force to the sail (around 6% less) but it also rolls the boat leeward. The only moment arm keeping the boat upright is the body weight. That’s why we lift centreboards when it is windy, it depowers the entire system.

[@elizabethmurray1475]

Thank you, J3zzaG. We will definitely look into this matter!

[@markcampbell7577]

What is usually missing from sailboat design today is keeling design that has lateral resistance ahead of sail effort. The stem to stern academic keeling design reduces heeling over and increases speed of the sail boat. Most importantly this keeling design keeps the boat easily sailing into the wind and the sailor can easily keep the bow to waves and wind. This lateral resistance ahead of the sail area is essential to create lift and have greater speed.

[@markcampbell7577]

The stem is halfway between the mast and forestay of the largest sail. This is the point where keeling of the headsails begin and should relative to the sail area ratio of mainsail and headsails.

[@tobiasharvey5924]

aw. i really miss engineering! great explanation. great job!

[@franzfranz131]

RESPECT = GREAT PRESENTATION

[@daviddoherty4429]

Thanks , very informative video

[@varunpanday2494]

Great job..I was looking around for an explanation like this vs just being out on the water and making sure your tell tails are in the right direction to capture the wind .

[@danbanowetz]

Overall nice video, but I believe you have a significant error. At 9:45 your free body diagram indicates that keel force is going the same direction as the wind force. Since it's on the opposite side of the center of mass, this would indicate the keel force is creating a moment that counters the winds healing force. This is incorrect. The keel force goes in the opposite direction of the wind force. The keel force prevents the boat from side slipping, not healing over. The weight of the boat and sailor resist the boat from tipping over. This can be easily proven, if you're reaching quickly across the wind, healed over, and you pull out the center-board (keel) the boat will not flip over, it will side slip across the water. Hope that makes sense and you can correct this.

[@captainmee3469]

thank for the lesson... really great explanation....

[@markcampbell7577]

The center board should be directly below the mast and ahead of the mass. If you keel the boom the boat heels over before moving forward and has less sail power..

[@adrianvalbuena8158]

Thanks for the video Emma!! I really like the visual examples. I will apply someday with my students!!

[@markcampbell7577]

The force vector ratio from width of the boats is the trimaran and catamaran design. A catamaran should be built in have a force vector ratio that is three to one. HtoV. The horizontal force you can capture before the boat heels and you lose wind power.

[@markcampbell7577]

This width is.....67.5 midmast to pontoons for a catamaran. The sailboat design is twice as wide as the boat is tall. Also known as the Cleopatra's barge. The fastest boat design ever conceived and built.

[@shalomccs]

Thank you for your explanation. Good to install a small one in my kayak!,,,, for experimental purposes.

[@sotirissalloumis6129]

Thanks for sharing, very useful and helpful.

[@lubabai9922]

I thought I saw velocity spelled with an s somewhere in the video. At 7:37 I think. Bottom left corner. Thanks for making the video though. It’s helpful.

[@markcampbell7577]

When will not keel the mast and headsails to sail upright and faster? Stem to stern keel line or wing keel and blade keeled head sail. What if you keel the mast accurately at the mast and remove the unkeeled headsail?

[@jbszee]

Great video. Thanks! Were the Tech Dinghys replaced? It's been a long time since I sailed at MIT. Course III, '81.

[@mvs3553]

What do I do with my hands?

[@hisoka44444444]

I was curious and anticipated some of the forces&moments that would be in play, but I learned a lot about the centerboard & other aspects, good explanation! Thank you :)

[@juda6800]

When it comes to demonstrating the effect of the force created on the profile in a stream, I prefer an ordinary soup spoon with its convex surface close to the stream of running water coming out of the tap. You can see and feel it. No appealing to Bernoulli's law or looking at the wing of a jet-powered airplane.

[@InsightfulMindsIntelliNexus]

Great video Emma!

[@markcampbell7577]

The stem is the most important design quality of a sailboat design. Ballast the boat and keel the sails.

[@brinjal1371]

How to become sailing instructor?

[@markcampbell7577]

The fastest direction is across the wind. The apparent wind ahead of the boat ends the speed of the boat.

[@anthonyellis9804]

What does the B/D ratio have to do with vessel performance?

[@jonathangosselin3028]

good video , you now have 1000 likes:)

[@MichaelHolzmeister]

Has any one ever seen an experiment proving the hypothesis that air destined to travel over the top of a foil increases its speed when it encounters the leading edge of the foil and begins its longer trip over the top? One could add two pulses of dye into a slip stream so that they travel on either side of a foil. The expected result, according to the explanation of lift in this video, should be the pulses arriving at the trailing edge in exactly the same relation that they arrived at the leading edge despite one pulse having to travel a longer distance. The pulse had to have received a force in the trailing edge direction to increase the speed component of the velocity. What generated the force int he trailing edge direction that increased the speed of the pulse that went the longer distance?

[@notwhatiwasraised2b]

this is over any newbie's head just go find a sailing school and learn hands on it's too easy to over think sailing

[@markandoyo2204]

Have you also investigated regarding LWL over the Hull Speed as yet conceptualising the boatbuilding with short LOD with wide Beam but all of my hull concept obtained semi displacements hull as enough to configurate proper ballasting systems using Gaff Rigs as main sail as yet I mention a pocket yacht with 16 or 17' LOD under the 20 or 21 LOA as though I was not properly schooled with degree but technically under the domestic doctrine standards nobody believe me with extra-curricular property especially within these curriculum aren't been part a standard curriculum here, as fell short some degree of misunderstanding enough to call me a delus

[@markcampbell7577]

The surge of lift is greater than the power of jamming.

[@chuckboris7275]

That's why i like youtube

[@jimmybaggs5342]

Anyone know the model of dinghy she is sailing?

[@markcampbell7577]

The keeling of the mast at the mast is often missing.

[@markcampbell7577]

The mast should be keeled and the headsails keeled more deeply between the mast and forestay.

[@markcampbell7577]

So the downwind quarter is the fastest quarters to sail.below 90 degrees to the wind. 2.0 times windspeed is maximum boat speed. But perfection is not a realistic goal. Vesta's speed can be reached in a full size sailboat design of normal academic design. If the keeling design is correct and the width is twice the height of the mast or greater.

[@grokscience8673]

Noticed this was some 3yrs ago. I'd love to know what the young lady is doing now.

[@00bikeboy]

You should explain what a "moment" is. Not everyone has a degree in mechanical engineering.

[@youdontwanttoknow5203]

Can you slow down please? Maybe telling people what they need to do first and explaining "why" later for people with very little physics experience.

[@yanassi]

On a technical level it’s very interesting. But really, i fell asleep

[@williamelica4522]

Thank you I'm William Elica & I'm planning to voyage from lat 20° north longitude 121° east. To Sydney , My late father the best friend of American coastguard here in Batanes island Philippines ,Thank you white Americans to give me reference

[@woke72]

The wind is lifting the sail not pushing it.

[@anthonypropst1818]

I know she's right, but my cranium exploded about 6 mins into the video. LOL I should have planned to watch about 2 mins of it a day for 8 days so as to keep that from happening.

[@chikokishi7030]

Why is that sailboat model so beat up? and its got a wood screw for the front bearing lol

[@genericyoutubeusername6462]

Oh .. I dont get it. Bernoli or whatever air thing is never makes sense It cant generate enough lift to lift a 300 70kg adults and fuel and avionics right ? .. along with its own weight. .. the perpendi doesnr make sense

[@skipper1350]

I always thought yachts more or less got sucked along, not blown along.

[@the3squire]

Send Free Body Diagrams

[@jonnymilitia]

All i heard was words. I i kinda get it. Im knowledgeable with planes and helicopters and understand them easily but i just can't grasp sail boats.

[@mitchrc3]

Nerds rule. Nerds make the rules too. : )

[@Rdebeauvoir1]

I looked at your eyes the hole time!

[@markcampbell7577]

The keel is in the wrong place. The keel should be at the mast. The following edge of the keel matches the following edge of the mast. This on keeling.

[@markcampbell7577]

The on keeling should be faster. An experiment should settle the question about speed.

[@lets_go_see_]

Yes, she does a great classroom production but it comes across very fast and clinical. Unfortunately people like me who are able to learn complex situations fall asleep in clinical classes.

[@prun8893]

They don't teach spelling at MIT.

[@markcampbell7577]

The sailboat can sail up to twice the speed of the wind but this is theoretically perfect number and not physically possible. 1.5 times the windspeed is a realistic goal but without stem to stern academic keeling design this ambition can't be seen.

[@lithe.susurrous661]

You remind me of Abby from the Last of Us Part 2

[@judoz420]

Im here because of Atlas lol, still confused

[@alextheboatguy399]

I dont watch sailboat races I participate in them

[@McLuvin411]

Beep boop

[@calinraulpopp4541]

0

[@judithnicholais1492]

Going way too fast for so much technical info ...

[@SIDEKICKONYOUTUBE]

i guess there is no easy way to understand this.

[@hashirwaqar8228]

unpopular opinion : very confusing and overstuffed presentation .

[@assifkhan3803]

Sorry to hear that you have a point of view.i believe all videos have value for someone somewher.i liked it for it's detailed content and can refer back to it when I need to explain how it all works.some of this I learnt in my physics at the age of 13.so when I came across it I could relate to all of it

[@ronmit-p5g]

wow it looks like she is having so much fun! she is definitely not reading anything

[@herbjohnston6404]

You....are....a.....dbag. z This is a pretty well organized, comprehensive video and helpful to those of us trying to really understand the physics of this amazing lifestyle. Unlike your id10tiodic comment which is helpful to no one.

[@roginutah]

MIT? Not the right explanation. Dang.

[@rickc303]

Dat gap

[@zakmorris4038]

i just wanted to learn about sailing but ended up just staring at the pretty girl the whole time

[@missionsabai.sail.behappy.8313]

decent video, but i think you missed the public speaking class....then i fell asleep due to the monotony

[@trackie1957]

Uncalled for, and I disagree. She spoke very clearly and energetically. Her work made a positive contribution to teaching sailing.

[@missionsabai.sail.behappy.8313]

@@trackie1957 oh settle down. go find a safe space