@@Datain3d22 Yes it’s because 8 minute videos allow the placement of a mid-roll ad so they make more money from a single video! I’d rather make and watch two 4 minute videos though…
Thanks I’m glad the analogy made sense! There are some subtleties that could benefit from more depth of explanation, like the models of the atom we learn about in high school, but I was really trying to come up with a good way for people to intuitively understand what’s going on!
@@wasserwasser5555 The second force comes from the (sideways lift of the) keel moving through the water. That force gives the force from the sails something to act against. If it didn't have that second force, the boat would not be able to move (efficiently) when going against the wind (upwind). It would only be able to go with the wind (downwind). (A vector diagram would be a more traditional way to show this, but maybe less intuitive without an explanation of vectors.) If you squeeze a slippery watermelon seed between thumb and forefinger, it can jump forward and pop out. Without the second finger, you can only push it.
Fun fact, old sailing boats used to put the worst smelling facilities at the front of the ship, since the wind would carry the smell forward and away from the ship.
@@KevinColt that's basically how the toilets worked, with a common setup being a communal trough made of a long plank with 3-8 holes at the front of the ship where you're basically sitting over the side and (mostly) shitting into the ocean. The sea itself would clean off most of what hit the side of the ship and the rest by the poor barnacle boys.😬
as a young (16 year old) guy, I sailed a Comet with my younger brother on Lake Hopatcong in NJ, if we had a 6 mph breeze against out main sail and jib, we could easily reach 10 to 15 mph depending on hard we haled the mainsail close to the plane of the 22 ft boat Eventually, the 90 year old canvas mainsail exploded and we never had the resources to repair or replace it.
had a 18 foot maricat when i was a teenager. nothing to do with this video but mate was it one of best feelings to get it up on one side and ride the wind.
I'm not into boats but I am into knowing things. This video was randomly recommended and it was very concise and easy to understand! How does the boat start and maintain movement tho??
Excellent question! A sailing boat can sail in any direction relative to the true wind except straight into the wind as well as a no-go zone about 45 degrees to either side of that (look up points of sail). To get started you need to position the boat with the bow facing any direction other than the no-go zone, with the easiest being across the wind i.e. bow 90 degrees off the wind. Then you pull in the sails and the boat will accelerate. Once the boat is up to speed, the helmsperson can either steer the boat to keep the sails optimally aligned to the wind, or the crew can adjust the sails if for some reason the boat can’t be steered to the wind e.g. there is another boat, an island, or you simply want to go in another direction relative to the wind. Does this help?
@@SailingTipsCa This is a perfect answer, but in practical terms, most sailboats that folks are likely to encounter have motors that sailors used to move the boat into a position where they can start to sail using the wind. For smaller boats with no motor, such as a beach catamaran, sunfish, or even windsurfer, etc., this is exactly what you do. Even for boats with a motor, getting under way without using it is much cooler. Sailing off a mooring comes to mind.
@@LoanwordEggcorn I don't think the original question was "how does a sailboat get to a place where they can raise their sails and start sailing" it was more how does it start moving before it's moving faster than the wind? I'll grant you though that sailing off a mooring is cool. I did that on my last BVI charter. Conditions were perfect - uncrowded mooring field, perfect wind direction to get out of the bay, and relatively light winds. I waited until we swung a bit, unfurled the jib and dropped the mooring and away we went. I was hoping people were watching and applauding my seamanship but I'll never know.
@@tmhudg I applaud you. :) But you also get the cool points of knowing you did it. :) More sailing sooner is definitely cooler than motoring. And you're right, the original question was more about how to get the boat moving in general, and the answer was exactly right. (Using a motor is how most people do it, but not really the answer to the original question. I think I did mention that, and wanted to point out the realities of how it happens most of the time for non-very small boats.) If there's enough wind to sail in general, there can be enough wind to sail off a dock or mooring, BUT most moorings/docks/anchorages are usually in relatively protected waters, so the wind will be lighter. It may be too light to sail from. Minor correction, most displacement boats, especially monohulls) sail slower than the wind most of the time unless they're very efficient. So it sounded like you were being a bit optimistic to sail faster than the wind. :) Anyway, agree with your comment. Fair winds!
00:16 İt's not inefficient because they need force in those big heavy ships instead of speed and it should be able to continue travel even when wind is weak if they were using other sail types it would be like trying to go in fifth gear when you're literally unable to even go as fast as 40 km/h, so don't make old tech look like bad those sail types was so efficient but if you are going to manufacture a car with 18 wheeler truck transmission than it's Gonna be trash
Yes but if those old sailing ships had the exact same sail area configured more as wings like a schooner or modern sloop even they would have been faster!
@@SailingTipsCa they were already have that knowledge but they didn't because it wasn't practical when average wind speed on ocean is not more than 6 m/s and a bulk ship designed for travel usually and get wind speed higher than 8 m/s rarely even if it was designed like that you said it would get higher max speed but it would cost them ridiculous amount of average cruising speed when it's most important specification is that also those ships had hull speed as a limit and when you reach %80 of hull speed amount of power to get speed gets ridiculously high till you exceed that speed and Start to Surf on water and as you can guess if you were able to get that speed still you would need a very high power for a short time to exceed the hull speed than you would be able to maintain that speed but you wouldn't get that powerfull short wind so don't underestimate old tech and don't spread misinformation
@@eshabbatan9411 The ship at 00:16 is the Batavia completed in 1628, and wings weren't well understood by humans until at least the mid 1800s, so how could they have had that knowledge then? Also, how would a wing-shaped sail that would enable them to sail at a higher percentage of the wind speed/hull speed be a bad thing? These old ships were also very vulnerable to lee shores and many were shipwrecked because they couldn't' escape and were blown onto the rocks, so wing-shaped sails that enable them to sail upwind would have been very helpful, even if they couldn't exceed hull speed.
Look at junk sailing boats they knew the only way to travel wasn't drag force but because of strength and durability they made ships with fixed sails so much also you said with the same wing area you could make it much more powerful yes it's true but with same height you couldn't make it more powerfull and you can't make so high sails because it would lay down the ship so you would rather a low center of gravity(within the lift and drag force of wind, I don't talk about center of mass) so a wide horizontal sail would be better than a vertical very high (maybe 4 times longer than ship length)
I mean the cost of sailing faster was so much so they didn't use it because in those times sails and woods were less affordable think about that at those times your problems were not depression or something like that your problem was that you are hungry😅 you need a home to be protected you need water and basic needs like that so it was just a luxury to be fast but making the most basic ship was a need
Good example with the cap. On a side note, airplane also use multiple vectors of lift. Yes, the wings lift upwards, but also, lift from the propellers provides lift in the forward direction, although we then call it thrust. Still, the blades are still utilizing the Bernoulli effect with an airfoil shape to utilize high/low pressure differentials. Even jet engines require these differentials internally in order to provide the pressures necessary to initiate jet propulsion. It's all about the pressure.
That's why a C130 Hercules can take off with more weight than the wings can lift at takeoff speed. Those 17,200 horsepower virial pitch turbo prop engines can cork screw the plane up in the air until the airspeed increases to the point where the wings can do there lifting.
Bernoulli effect requires a difference, or change, in air velocity, and the difference in air velocity results in changes in pressure. Usually that is provided, in a pipe, by a constriction of the flow area of the pipe (e.g. a venturi in a carburetor). There is no such constriction for a sail as it is open on both sides. I assume this comment, by invoking Bernoulli, is saying the sail generates a difference in air velocity from one side of the sail to the other. What causes that difference in air velocity? Or is it perhaps that the sail generates a pressure difference across the sail by diverting the air, and the pressure difference is then the ***cause*** of the difference in air velocity, and not the other way around?
@@BrianTCarcich Yes, anything with an airfoil shape (wings, sails, hydrofoils, props...) is designed to create a pressure difference in the flow of air or fluid on either side of it. That difference then creates lift or thrust, depending upon the application, and it's all fundamentally Bernoulli's principle at work. Dude was such a genius. So, in the case of a sail, as with all airfoils, this is due to the shape being more rounded on one side and more flat or even concave on the other. This makes the air travel faster around the downwind side of a sail, creating a low pressure zone compared to the upwind side. This in turn produces the forward thrust of the sailboat through the sideways 'lift' of the sail, which is actually more of a diagonal force relative to the boat for most directions a sailboat can go. Not sure if I'm explaining this very well, but there are tons of interesting articles and TH-cam videos that do a great job describing how Bernoulli's principle applies to sailing if you're curious.
I was conceptualising about how sandships would work in my worldbuilding project and this came to my recommendations. Thanks for the vid! very informative~
I now understand a little bit more about what hydrofoils and dynamic keels do under water, and how it balances the sailboat to prevent it from keeling over and how it might drag, stall, or fail if sudden changes are applied to it. As a SailGP enthusiast, I'm grateful
Glad it makes a bit more sense now! You’ve probably noticed that once the SailGP boats fall off their foils it takes a bit of work to get them back up there because they have to overcome the drag of the immersed hull. Amazing machines!
@@SailingTipsCa To me the boat falling off or getting on the foils was as intuitive as changing gears, or picking up speed in a bike to help keep it upright. What puzzles me is the things done by the flight controller, and the wing trimmer tandem the grinder/s because the adjustments done by these guys aren't easily shown and maybe a competitive secret.
@@SukacitaYeremia I understand the flight controller will be constantly adjusting the angle of attack of the foils to keep the boat at the desired foiling height based on the boat speed e.g. less speed more angle of attack and vice versa. The wing trimmer will be positioning the wing to power up or power down the boat based on the prevailing wind speed and direction, and in conjunction with the course being steered. Both the foils and the main are hydraulically controlled with pressure created by the grinders.
We call it creating your own wind (on low drag boats), thats why the appearent wind always comes from the front(and way stronger then the real one), even on reach or broad reach, but you cant do it downwind. You have to reach and jibe downwind.
Great question - it really depends on the boat. Some have asymmetric foils that they raise and lower at each tack. This is the most efficient solution hydrodynamically but involves more work for the crew and precise timing. Others have symmetric foils where lift is generated by altering the angle of attack, normally via the helm/rudder in most boats.
What a nice information! I have worldbuilding project and want to gain insight to how one can make Old Imperialism era sailing ships, so your video helped me. Thank you!
sailing is not an interest of mine, but your video caught my eye. thanks for that explanation :) i'm a land lubber but hydrofoil ships have always interested me. esp the USS Pegasus. it just seems like a no brainer to lift the hull out of the water. (thank you material science for developing such amazing composites :) ) but your lift explanation makes a lot of sense to this virtually virtual pilot :)
I’m glad it made senes and captured your interest! Note that boats that can plane on top of the water can also sail faster than the wind, but still not as fast as hydrofoilng boats that lift the hull out of the water. It’s all about lift vs. drag.
Explanation via forces and vectors: Drag (force in N) in - opposite - wind direction, Lift (force in N) orthogonal to Drag. The vector of the resultant force is splitted other wise: into sailing direction and orthogonal direction. The force in the sailing direction moves the boat forward and the other one heels the boat sideward. The keel must be heavy to create the sufficient righting moment in order to prevent the capsize. de.wikipedia.org/wiki/Physik_des_Segelns#/media/Datei:Wirkung_des_Windes_bei_Amwindkurs.svg
Nice diagram - thanks for sharing! Yes the sails generally create more heeling force than forward drive. Most boats use heavy lead keels to create righting moment and counter heeling, but some boats (e.g. multihulls) use floatation and the weight of the boat itself to counter heeling, while others (e.g. foiling boats) use hydrodynamic forces in conjunction with the weight of the boat.
Interesting. I wonder if you can apply same principles in electromagnetic fields. Will the boat sail faster if the was 3 forces pushing it in a same manner? Is there an angle range for the most efficient thrust? Thank you
I think you could use this technique in any low-friction environment with opposing forces and the third dimension could be levitation which would result in very low drag/friction! I think the optimal angle is a function of the amount of drag/friction, whereby less drag enables tighter (i.e. more acute) angles and higher speeds, whereby more drag/friction requires larger angles but results in lower speeds. Think of it like gears in a car or bicycle!
@@scottwooster4102 I think he does, apparently his bread and butter is filming driving scenes for car commercials. The other benefit of a boat is that your can camp on it, have a barbecue on it etc so there is more utility in many regards.
That was very informative. Thanks! Question: let’s say steam and combustion power was never invented. But these effects became known. Could practical cargo, passenger, and warships have been designed using these principles? Or would the lack of modern materials not allow these type of ships on a practical level?
Excellent question! Cargo, passenger and warships did all have sails at one time, with schooners being amongst the most advanced of these, but they were all still reliant upon the wind, which is inconvenient if you have to be somewhere at a given time and the wind isn’t blowing. I don’t think materials is a constraint these days, but schedules definitely are! Sails also generally require larger crews compared to motorized vessels which creates an economic constraint as well. Still it would be possible without motors!!!
Really - why do you say that? I understood lift to generally be perpendicular to and corresponding in magnitude to the curvature of the foil. Therefore with symmetric foils which most boats have the lift would be perpendicular or slightly forward of the centreline of the boat no? resources.system-analysis.cadence.com/blog/msa2022-exploring-the-aerodynamics-of-symmetrical-airfoil
I knew sails worked like airplane wings but always thought the lift of the sail "pulled" the boat. It did not occur to me that there was another foil underneath and the boats motion is the resultant of these lift vectors. Short and sweet vid.
there's a crucial detail that should be noted. High performance class boats are able to go faster than true wind on up and downwind lines due to the design that allows the boats to manipulate apparent wind in an unconventional manner. The best example of this is when the AC72/75 is downwind, the trim is changed to an upwind mode as when it is travelling faster than the true wind, it's as if the wind is going backward! So technically a jibe is in actuality a tack
Yes it’s not uncommon for faster boats to be sailing “upwind” all the time! Even my “slow” F-82R trimaran can “bend” the apparent wind forward by up to 90 degrees so we’re always sailing with the apparent wind forward of the beam even under spinnaker!
This is the part that breaks my brain (old school sailor). When AC boats are jibing downwind I just can't comprehend what is happening. Is there a point where they switch from tacking to jibing if the wind drops?
@@tmhudg The term “tack” is typically defined by turning the bow of the boat through the eye of the wind, whereby a “gybe” is turning the stern of the boat through the eye of the wind. With an AC boat the key question then becomes whether this definition is based on the true wind or the apparent wind. Turning the stern of an AC boat through the eye of the true wind may technically still be a gybe, but it will certainly feel like and be executed like a tack because the apparent wind in the faces of the sailors and on the sails from ahead will generally be stronger than the true wind from behind. Those who have sailed them (not me) can probably say for sure, but given their efficiency I don’t expect there to be any conditions where they would choose to sail with the apparent wind aft of the beam, so a gybe would probably always feel like a tack.
@@SailingTipsCa That makes sense but there are things that still are hard to grasp. Like when rounding an upwind mark, what changes are made to the sails when going from sailing "upwind" to sailing "downwind"? I get that the apparent wind is still coming over the bow(ish) but it certainly lessens as they turn right? Are they trimming sails differently? In lighter wind (and therefore slower boat speed) is there a point where, when turning to go downwind, the apparent wind is aft of the beam? If so, do they then have to do "normal" gybes at that point?
@@tmhudg Great questions! The apparent wind angle will be the tightest (as measured from the centreline of the boat) on the upwind leg and will be slightly lower on the downwind leg. So just like any boat the sails will be fully sheeted in as tight as possible for the upwind leg, and eased as the boat rounds the windward mark, but not by much, something on the order of 20 degrees (again as measured from the centreline of the boat). So close-hauled upwind and close reaching downwind. On my boat, which is much slower than an AC boat but still sails faster than the wind, it is pretty much always fastest to sail with the apparent wind forward of the beam, even downwind in light conditions. This is because the lift created by the sails is always the greatest when you can get the wind flowing across them like an airplane wing, and the extra distance sailed is easily compensated for by the increased speed.
No it’s not necessary to use a hydrofoil to sail faster than the wind and several other non-foiling boats like dinghies, multihulls and planing sport boats can also sail faster than the wind with just vertically-oriented daggerboards and rudders, albeit generally not as fast as hydrofoils. That said the around the world sailing record is still held by a non-hydrofoil multihull. You just need a sufficient amount of lift from the sails and underwater appendages versus the drag in the system.
At last! Someone who explains method WITH CLARITY! Those who pretend to know, tap the side of their nose. Thank you, ST - your two rod analogy (squeezing the boat faster than wind-speed) is now my firm imaginary model.
You don't need to invoke Bernoulli / foil lift principles to explain why a boat can travel faster than wind. You even showed the effect with the disc, and you had no foil present. It's just vectors and "sliding surfaces" or an angle of attack.
Yes in retrospect showing lifting foils makes the video slightly more confusing than it might have been with another boat with the high lift versus drag ratios like a planing dinghy, sport monohull, or multihull. Otherwise you’re right it’s about vectors.
There is a blend of two explanations merged in to one. Daggerboard and foil. These are different things although both under the boat. A foil has nothing to do what a daggerboard does and vica versa. Foil lifts the boat out of the water so drag is strongly reduced to get more apparent wind Daggerboard is a vertical device which has, usually, not the shape of wing. The boat has to go in both directions. It prevents the boat going sideways
People tend to think only of lifting foils with the term “foil” but daggerboards, rudders, and lifting foils are all technically lift-generating foils that have different orientations and different jobs under the water.
Possibly, but I think that’s also a factor of the waves slowing down in shallow water while at the same time getting steeper which provides more of a “slope” for the surfer to slide down and outrun them!
Vectors and mechanical advantage. How does a block-and-tackle gain so much advantage? How does a crowbar gain so much purchase? How does a wind turbine, turning a 15 RPM turn a generator of 1,500 RPM?
Yes there are indeed a lot of factors! I mention how apparent wind builds and “bends” forward at around 2:15 of the video, and keeps building as the boat accelerates until the lift equals the drag.
You say that this would be impossible to do without modern materials. Could you not get a similar, though lessened effect with traditional materials? What is the most technologically primitive (in terms of construction) you could get to make a boat that utilizes this principle?
Yes there are some planing dinghy designs that can be built from very thin marine plywood (e.g. Fireball) and still sail slightly faster than the wind on certain points of sail, but not 2-3 times faster on all points of sail like a carbon fibre full foiling design. You can also build some Farrier trimarans using cedar strip construction that will sail slightly faster than the wind. In both cases you will still need some composite components to hold things together e.g. glass fibre, epoxy. Is this what you meant?
@ Kind of, yeah. Imagining if one was thrown back in time, or survived after a nuclear apocalypse, could one use this tech, without today’s industry. Setting up the keel wing doesn’t seem too out of the realm of possibility, so would be a matter of getting the sail rigged right, I think.
@@Skyblade12 You could definitely build a decent-performing boat from wood, but then the limitation becomes what kind of glue you have access to and whether you have plywood or are milling your own trees.
Have you heard about people who have sailed into the earth via the north pole? Many books and stories on sailors who have sailed into the earth via the north or south pole to the agartha network of cities. Amazing video about sailing and the wind.
Is there a difference in speed when going upwind vs downwind in the same conditions (edit: angled to the wind for max speed)? Also a vector question. Mostly it's rhetorical, because I'm sure it differs depending on the boat, but mine is a sailing dinghy with a cat rig (edit: not a keel boat, but let's pretend it is). I'm wondering if the goal is forward motion would you end up at the same place at the same time in a dead run versus a broad reach. Obviously upwind has no corollary (edit: actually it does, would you end up at the same place at the same time in a close haul vs the speed of the wind?).
Good questions! Yes there is generally a difference in speed upwind vs. downwind relative to the true wind, and that difference depends on the boat. In my boat I max out at around 12 knots of boat speed when sailing as high as possible into the true wind, but can sail at 20+ knots off the wind. For all boats the fastest way upwind is tacking through 90 degrees, and for fast boats the fastest way downwind is also gybing through 90 degrees relative to the true wind, as this keeps the apparent wind forward of the beam which keeps the sails working as wings and is much faster than sailing dead downwind. When sailing dead downwind you can really only go 50-60% of the true wind speed, say 5-6 knots of boat speed in 10 knots of wind. But gybing through 90 degrees downwind my boat could go 12 knots in 10 knots of wind, so twice as fast, but only sailing 1.4 times the distance, so velocity made good (VMG) towards the finish is better even though we're sailing further.
Assuming the same apparent wind angle, the max. downwind VMG is 1 true wind speed greater than the max. upwind VMG. But that is only valid for very efficient sail craft like those foiling boats, or ice boats.
There is type a plot called a speed polar that gives the speed of the boat for all directions relative to the true wind. E.g. see here www.google.com/search?q=sailing+speed+polar&tbm=isch Offwind (when the dot, a.k.a. scalar, product of the boat's velocity vector with the true wind velocity is positive), for some boats the downwind component of the boat's velocity vector is greater than the true wind's velocity vector. So those boats, with velocity vectors 10-30° off the true wind vector, could beat a balloon blown from an upwind mark to a mark directly downwind, even though those boats would go out to the side with respect to the straight downwind course, gybe, and come back to the downwind mark.
Hi. Very good vid ! I have a question - what is "needed" to go faster than wind ( is your Tri able to do so ) ? Would be very interesting video to create - It could be called: " What is needed to go faster than wind". Wing mast ? Power to weight ratio ( Sail area to displacement ) equal to ... ?
Good question and video suggestion! Somebody once told me that everything in sailing comes down to lift versus efficiency and I think that applies here too. Our F-82R trimaran can sail at around 1.2 times the true wind speed, but it has no lifting foils and relies entirely on floatation for righting moment. Off the top of my head I think that what you "need" to sail faster than the wind is: 1) A powerful sail plan - most boats that can sail faster than the wind have huge flat-top mains, a rotating mast also definitely helps here 2) A hull that is not constrained by displacement hull speed "rules" (i.e. 1.34 x sqrt(waterline length)) so either a planing hull for a monohull, or a multihull with long skinny hulls and a length to width ratio of greater than 8:1, or lifting foils 3) Enough righting moment to keep the mast upright without impacting 2) above, so for a monohull a canting keel definitely helps Interestingly I have a friend with a Cheetah 30 sport boat, which has a very similar sail plan to our F-82R, a planing hull, and about the same boat weight, but the Cheetah is much harder to sail faster than the wind because we run out of righting moment and get knocked over as the apparent wind comes forward. In fact the F-82R has about five times the righting moment of the Cheetah and as a result the F-82R rates about 30 seconds per mile faster. The F-82R also has a rotating mast but I think the righting moment is the biggest contributor.
I have a 24 ft monohull with a Dacron sail. While it is light and efficient it has no foils or Alma’s ( outrigger multiple hull sponsons). I frequently sail at wind speed + 2 knots. The trick downwind is to not sail exactly downwind but off the wind in order to create the draft effect on the sails. That’s why you see sailboats jibing downwind to get to a point that is directly downwind from the boat. Longer distance but much faster speed.
I like how in search of the "fastest boat" humanity step by step erased traditional hulled boat until the absolute, the platonic ideal of the fastest boat, looks nothing like traditional boat. 1) narrow hulls offer less resistance, lets make it as narrow as possible. 2) but the narrow hulls have stability problems, let's double the hulls. 3) fuck it, lets triple them while we're at it. 4) aaand to reduce resistance even further, let's completely lift the hulls out of the water. Congrats, you have modern racing trimaran "flying" on wings.
My prediction before watching the video: The forces must be equal, but a lot of slower air in a massive sail can equal the force of some small vanes going forward quite fast.
I would love to learn what the most well designed ship would look like, if it had to use materials available in the 17th century, and also carry cannons.
That would be very interesting, kind of like that test they did with modern sailors recreating Shackleton’s escape from Antarctica using period materials, clothing, and food!
I think over the 100s of years of sail ship evolution, they pretty much nailed it down what worked and what didn't. Ships wouldn't look much different, imo.
imagine what and old sailing ship captain would think if he came to the future and saw what a modern sailing vessel was capable of. he'd have us all burned at the stake for sorcery XD admiral nelson's HMS Victory plodding along at 9 knots and then an america's cup catamaran zips past him at 80 knots with its hull floating out of the water going UPWIND. their brains would melt trying to make sense of it.
I'd say the Captain would have understood the basic principles, but also figured out that our ships are far stronger and lighter than anything he had to work with. He would also have recognized that a ship designed to carry over 100 cannons plus their ammunition along with food and water for several weeks on high seas along with onboard repairs out of carried and local materials would be a very different design than a vessel optimized for pure speed over a matter of hours. The Captain would have been amazed at it and definitely want to take a tour of the catamaran, but he would have understood the basic principles.
@@toddkes5890 you're completely clueless. HMS victory was the cutting edge of naval technology in nelson's time, and it was powered by parachute sails. if he intuitively understood how airfoils and hydrofoiling worked he'd have been a genius on the level of newton. sailing upwind is so counterintuitive it took the human race five thousand years to figure out. NO ONE is gonna say 'that makes sense' just by eyeballing it.
@@toddkes5890 Those >100 cannons and their ammunition is going weigh a lot so hopefully anybody with access to high-tech sailing materials is also going to have access to high-tech weapons that are a bit lighter!
@@oldfrend He didn't fully understand the airfoils and hydrofoils, but the Lateen sail that allowed the airfoil effect of sailing upwind was developed in 900 AD. That is over 800 years before HMS Victory was laid down. He would not have known the mathematical models to get optimal performance, but as a Captain of a warship in a nation that relied on the skill of its ship Captains, he would have understood the basics.
Yes a static situation could generate lots of force but to generate electricity you generally need to spin a magnet inside a coil of wires (or something similar) so you need the motion!
Good question - there needs to be enough of the vertical foil component left in the water to counteract the force of the sails and drive the boat forward, so teams need to be very careful to lift the hull out of the water but not lift the boat too high so they loose the lateral thrust vector.
My understanding is water is essentially incompressible, especially under normal conditions. It's why depth charges work. So how do you have areas of high (compressed water) and low pressure (expanded water) under the keel? Especially as the (compressive??) forces involved must be tiny. 1m.38s
"Essentially incompressible" means that the volume doesn't change much, despite high pressure differences, not that there are no pressure differences. The air that interacts with the sail is also "essentially incompressible" at those speeds (way below Mach 0.3).
Yes incompressibility relates to water not changing volume much under different pressures, not that it can’t be under high or low pressure! It’s the low pressure that substantially lowers the boiling point to be at or near the sea temperature. Check out this video on Vestas Sailrocket for more info on that! How Did Vestas Sailrocket 2 Smash the Sailing Speed Record?!?! th-cam.com/video/K3m06731BQY/w-d-xo.html
You can definitely change the pressure of water in sailing and marine applications. Just look into propeller-driven cavitation if you don't believe me.
I think this is a far better treatment than Veritasium's one (where he didn't even understand the principle himself, did an actual experiment, and his best explanation was to quote the mathematics).
The simplest physics explanation is that momentum is always conserved. Mass 1 x velocity 1 = mass 2 x velocity 2. Clearly it is possible for v1 to be different than v2.
@@stingtheweimaraner that is where efficiency comes in, specifically: Above the water, the limit is set by the efficiency of the sail diverting the side (cross-boat-velocity) component, which is constant, of the apparent wind relative to the increasing drag of the anti-boat-velocity, which increases with increasing boat speed. Key points: the only thing the sail has to work with is the side component of the wind vector, and that does not change with boatspeed; what does change is the angle of the wind on the sail i.e. apparent wind moves forward with increasing boatspeed, and that affects the efficiency with which the sails operate. Below the water, basically the same thing: the side force, and therefore the leeway velocity, is more or less constant; the drag of the underwater surface increases with boat speed. So the ability of the sail to generate forward force, i.e. its efficiency, decreases with increasing boatspeed as the apparent wind goes forward, while the drag forces increase with increasing boatspeed. The speed limit is reached when the forces are balanced.
Yes it all really comes down to lift (from the sails) versus drag (from the sails and the surface the “boat” is “sailing” on. Ice boats and wheeled land yachts (e.g. blo-karts) can easily sail faster than the wind because there is so little drag with the surface they are on. They use the same principles in this video but with one rod stationary and representing their lateral grip on the surface. It’s a bit harder on liquid water because there is much more drag. Lifting foils help reduce drag, but they are not necessary for all boats as there are also many other types of boats (e.g. planing dinghies, multihulls) that can still sail faster than the wind without lifting foils.
Does the underwater daggerboard kill sea life? I mean can like a whale or porpoise or fish or sea turtle hear the sailboat coming and move out of the way or are they just sliced open? Is there anything mankind does that doesn't hurt nature?
It’s certainly possible that an underwater daggerboard could harm sea life, however they do tend to make quite a bit of underwater noise which gives most sea life ample time to get out of the way.
Is it rue that the water left behind the trailing edge of the foils on the AC cats gets as high as boiling temperature? Seems hard to believe, I know, but I read that somewhere a while ago.
You probably mean cavitation. The water is not boiling because of high temperature, but bubbles are forming because the pressure is reduced by the foils.
Yes it’s more a matter of the boiling temperature of water dripping towards sea temperature due to the low pressure, and not the water being heated. I show a clip of it in this video: How Did Vestas Sailrocket 2 Smash the Sailing Speed Record?!?! th-cam.com/video/K3m06731BQY/w-d-xo.html
@@joeblow1942 Yes, boiling temperature is pressure dependent. If you reduce pressure enough, water can form bubbles at the temperature of the sea. Look up "cavitation".
This is only true when the boat is not travelling in the same direction as true wind right? Can a boat travel faster than true wind in the same direction as true wind? Assuming the wind is constant
Fast boats typically tack through 90 degrees going upwind and also gybe through 90 degrees going downwind as that’s much faster than sailing dead downwind! In other words the are typically sailing across the true wind to some degree although the apparent wind they are experiencing due to their speed is always from ahead.
@@SailingTipsCa So for example there is an island 35km north from my boat. There is a wind heading directly north at 35km/h. If I travel exactly straight north in the exact same direction as the wind, it would take me 1 hour to get to the island? But if I zigzagged back and forth I could get there in faster than 1 hour?
@@mcdonaldslover52 Sailing dead downwind is not very efficient because you effectively “outrun” the wind so you’d be lucky to get 50% of the wind speed as boat speed so it will take you about two hours. On the other hand if you gybe back and forth in a zigzag you’ll travel about 1.4 times further, but you’ll also be able to achieve more than twice the speed so should be able to make it in about an hour in a fast boat.
@@mcdonaldslover52 yes, depending on the boat. Also, it is possible to build a land device (not a boat, but something with wheels) that can go DDWFTTW -- Directly Downwind Faster Than The Wind. It's been built and proven.
They make their own wind out of true wind. Its called "apparent" wind. I first noticed this in my Hobie 16 when both of us were on the wire. In a 15 mph wind my Dad's under powered runabout couldn't catch us even though he could reach 25 mph easily. He couldn't believe that we left him well behind. We were on a broad reach the fastest point of sail.
From my understanding, foils don't produce propelling forces at all. They lift up the boat vertically to reduce drag and stabilize it in the water so that the boat doesn't sweep sideways. I totally did not understand the physics of the foil's forces shown in your examples. 🤷♂️
The word “foil” is a general term for wing which can do multiple things: 1) a rudder is a foil that steers the boat 2) a daggerboard or keel is a foil that opposes the force of the sails to drive the boat forward 3) a lifting foil raises the hull out of the water to reduce friction. An efficient boat can still sail slightly faster than the wind with only the first two, but to sail at multiple times the wind speed you also need the third to lift the hull out of the water. The foil at 2:32 of the video provides lift in both the vertical and horizontal planes to carry out jobs 2) and 3) with a single foil. Does this help?
@@SailingTipsCa 1:50 - Author. You misunderstand, therefore, you draw the balance of power incorrectly. Your 'Foil lift' propels the boat forward. This is nonsense. In fact, this force is always opposite and equal in magnitude to 'Sail lift'...
@@MikleM1 "2) a daggerboard or keel is a foil that opposes the force of the sails to drive the boat forward" is correct. The sails propel the boat forward, but won't do so without the opposing action of the keel or foil. Note that he is saying that the sails drive the boat forward.
@Timo Rieseler The video shows an "L" shaped foil that has a vertical, lifting part of the foil (which is horizontally oriented) to raise the boat out of the water and a horizontal part of the foil (which is vertically oriented) to counteract the side (component of) force from the sail. A single foil does two things: vertical and horizontal lift. Horizontal lift is always needed in a sailboat in order to counter the side force of the sail. It's also possible to have a foil that only resists the side component of the sail force. That's a daggerboard or regular keel. They have only a vertical member. There are several possible arrangements of foils, including ones placed diagonally that also provide both vertical and horizontal lift components from a single straight foil, curved or C foils, "J" shaped, "L" shaped, etc.
thanks for not having a 8 minutes long black and white session about canoes before getting to the point
Thanks - I hate drawn out videos too!!!
TH-cam algorithm pushing 8 min and longer videos has ruined the experience
@@Datain3d22 Yes it’s because 8 minute videos allow the placement of a mid-roll ad so they make more money from a single video! I’d rather make and watch two 4 minute videos though…
Incredible physics analogy with the two rods and the puck, most intuitive explanation I've ever seen of this
Thanks I’m glad the analogy made sense! There are some subtleties that could benefit from more depth of explanation, like the models of the atom we learn about in high school, but I was really trying to come up with a good way for people to intuitively understand what’s going on!
same. Excellent tool for explaining
i didnt get why there are 2 directions aka 2 rods? sail and wimd point in the same direction, wheres the second force?
@@wasserwasser5555 The second force comes from the (sideways lift of the) keel moving through the water. That force gives the force from the sails something to act against. If it didn't have that second force, the boat would not be able to move (efficiently) when going against the wind (upwind). It would only be able to go with the wind (downwind).
(A vector diagram would be a more traditional way to show this, but maybe less intuitive without an explanation of vectors.)
If you squeeze a slippery watermelon seed between thumb and forefinger, it can jump forward and pop out. Without the second finger, you can only push it.
@@LoanwordEggcorn Another great analogy for understanding the concept!
Fun fact, old sailing boats used to put the worst smelling facilities at the front of the ship, since the wind would carry the smell forward and away from the ship.
That’s a great tidbit! These days though you’d probably want to put those at the stern as faster boats are almost always sailing upwind!
Thus the name "head" for the old ship's toilets
@@HansEricReitmayer Lots of interesting origins to many sailing terms!
why not just shit on the water
@@KevinColt that's basically how the toilets worked, with a common setup being a communal trough made of a long plank with 3-8 holes at the front of the ship where you're basically sitting over the side and (mostly) shitting into the ocean. The sea itself would clean off most of what hit the side of the ship and the rest by the poor barnacle boys.😬
Finally a channel that asks for a like at the end, not the start. Great video. 🎉
Thanks - I find that annoying too when creators ask for likes before they’ve delivered the content!
@@SailingTipsCa TH-cam should auto detect it and delay the upload by 2 hours to teach creators to stop it.
as a young (16 year old) guy, I sailed a Comet with my younger brother on Lake Hopatcong in NJ, if we had a 6 mph breeze against out main sail and jib, we could easily reach 10 to 15 mph depending on hard we haled the mainsail close to the plane of the 22 ft boat Eventually, the 90 year old canvas mainsail exploded and we never had the resources to repair or replace it.
Sounds like lots of fun! Too bad you couldn’t repair the main…
had a 18 foot maricat when i was a teenager. nothing to do with this video but mate was it one of best feelings to get it up on one side and ride the wind.
Yes small multis are incredible fun!!!
Excellent demonstration 👏 forwarding this to a physics teacher
Cool - physics was one of my favourite subjects!!!
I'm not into boats but I am into knowing things. This video was randomly recommended and it was very concise and easy to understand!
How does the boat start and maintain movement tho??
Excellent question! A sailing boat can sail in any direction relative to the true wind except straight into the wind as well as a no-go zone about 45 degrees to either side of that (look up points of sail).
To get started you need to position the boat with the bow facing any direction other than the no-go zone, with the easiest being across the wind i.e. bow 90 degrees off the wind. Then you pull in the sails and the boat will accelerate.
Once the boat is up to speed, the helmsperson can either steer the boat to keep the sails optimally aligned to the wind, or the crew can adjust the sails if for some reason the boat can’t be steered to the wind e.g. there is another boat, an island, or you simply want to go in another direction relative to the wind.
Does this help?
+1
@@SailingTipsCa This is a perfect answer, but in practical terms, most sailboats that folks are likely to encounter have motors that sailors used to move the boat into a position where they can start to sail using the wind.
For smaller boats with no motor, such as a beach catamaran, sunfish, or even windsurfer, etc., this is exactly what you do.
Even for boats with a motor, getting under way without using it is much cooler. Sailing off a mooring comes to mind.
@@LoanwordEggcorn I don't think the original question was "how does a sailboat get to a place where they can raise their sails and start sailing" it was more how does it start moving before it's moving faster than the wind?
I'll grant you though that sailing off a mooring is cool. I did that on my last BVI charter. Conditions were perfect - uncrowded mooring field, perfect wind direction to get out of the bay, and relatively light winds. I waited until we swung a bit, unfurled the jib and dropped the mooring and away we went. I was hoping people were watching and applauding my seamanship but I'll never know.
@@tmhudg I applaud you. :) But you also get the cool points of knowing you did it. :) More sailing sooner is definitely cooler than motoring.
And you're right, the original question was more about how to get the boat moving in general, and the answer was exactly right.
(Using a motor is how most people do it, but not really the answer to the original question. I think I did mention that, and wanted to point out the realities of how it happens most of the time for non-very small boats.)
If there's enough wind to sail in general, there can be enough wind to sail off a dock or mooring, BUT most moorings/docks/anchorages are usually in relatively protected waters, so the wind will be lighter. It may be too light to sail from.
Minor correction, most displacement boats, especially monohulls) sail slower than the wind most of the time unless they're very efficient. So it sounded like you were being a bit optimistic to sail faster than the wind. :)
Anyway, agree with your comment. Fair winds!
Having down quite a bit of sailing when I was younger, I've been very curious about this. Thanks for a simple, clear explanation!
Glad it made sense!
3 mins! Explained in 3mins is just perfect!
Yes I prefer watching short videos too!!!
00:16 İt's not inefficient because they need force in those big heavy ships instead of speed and it should be able to continue travel even when wind is weak if they were using other sail types it would be like trying to go in fifth gear when you're literally unable to even go as fast as 40 km/h, so don't make old tech look like bad those sail types was so efficient but if you are going to manufacture a car with 18 wheeler truck transmission than it's Gonna be trash
Yes but if those old sailing ships had the exact same sail area configured more as wings like a schooner or modern sloop even they would have been faster!
@@SailingTipsCa they were already have that knowledge but they didn't because it wasn't practical when average wind speed on ocean is not more than 6 m/s and a bulk ship designed for travel usually and get wind speed higher than 8 m/s rarely even if it was designed like that you said it would get higher max speed but it would cost them ridiculous amount of average cruising speed when it's most important specification is that also those ships had hull speed as a limit and when you reach %80 of hull speed amount of power to get speed gets ridiculously high till you exceed that speed and Start to Surf on water and as you can guess if you were able to get that speed still you would need a very high power for a short time to exceed the hull speed than you would be able to maintain that speed but you wouldn't get that powerfull short wind so don't underestimate old tech and don't spread misinformation
@@eshabbatan9411 The ship at 00:16 is the Batavia completed in 1628, and wings weren't well understood by humans until at least the mid 1800s, so how could they have had that knowledge then? Also, how would a wing-shaped sail that would enable them to sail at a higher percentage of the wind speed/hull speed be a bad thing? These old ships were also very vulnerable to lee shores and many were shipwrecked because they couldn't' escape and were blown onto the rocks, so wing-shaped sails that enable them to sail upwind would have been very helpful, even if they couldn't exceed hull speed.
Look at junk sailing boats they knew the only way to travel wasn't drag force but because of strength and durability they made ships with fixed sails so much also you said with the same wing area you could make it much more powerful yes it's true but with same height you couldn't make it more powerfull and you can't make so high sails because it would lay down the ship so you would rather a low center of gravity(within the lift and drag force of wind, I don't talk about center of mass) so a wide horizontal sail would be better than a vertical very high (maybe 4 times longer than ship length)
I mean the cost of sailing faster was so much so they didn't use it because in those times sails and woods were less affordable think about that at those times your problems were not depression or something like that your problem was that you are hungry😅 you need a home to be protected you need water and basic needs like that so it was just a luxury to be fast but making the most basic ship was a need
Good example with the cap. On a side note, airplane also use multiple vectors of lift. Yes, the wings lift upwards, but also, lift from the propellers provides lift in the forward direction, although we then call it thrust. Still, the blades are still utilizing the Bernoulli effect with an airfoil shape to utilize high/low pressure differentials. Even jet engines require these differentials internally in order to provide the pressures necessary to initiate jet propulsion.
It's all about the pressure.
I’m also a closet airplane buff but sailing boats are slightly cheaper!!!
That's why a C130 Hercules can take off with more weight than the wings can lift at takeoff speed. Those 17,200 horsepower virial pitch turbo prop engines can cork screw the plane up in the air until the airspeed increases to the point where the wings can do there lifting.
@@Paul37Ontario Cool plane trivia - thanks for sharing! With some military planes the engines are so powerful the wings almost seem like accessories!
Bernoulli effect requires a difference, or change, in air velocity, and the difference in air velocity results in changes in pressure. Usually that is provided, in a pipe, by a constriction of the flow area of the pipe (e.g. a venturi in a carburetor).
There is no such constriction for a sail as it is open on both sides. I assume this comment, by invoking Bernoulli, is saying the sail generates a difference in air velocity from one side of the sail to the other. What causes that difference in air velocity?
Or is it perhaps that the sail generates a pressure difference across the sail by diverting the air, and the pressure difference is then the ***cause*** of the difference in air velocity, and not the other way around?
@@BrianTCarcich Yes, anything with an airfoil shape (wings, sails, hydrofoils, props...) is designed to create a pressure difference in the flow of air or fluid on either side of it. That difference then creates lift or thrust, depending upon the application, and it's all fundamentally Bernoulli's principle at work. Dude was such a genius.
So, in the case of a sail, as with all airfoils, this is due to the shape being more rounded on one side and more flat or even concave on the other. This makes the air travel faster around the downwind side of a sail, creating a low pressure zone compared to the upwind side. This in turn produces the forward thrust of the sailboat through the sideways 'lift' of the sail, which is actually more of a diagonal force relative to the boat for most directions a sailboat can go. Not sure if I'm explaining this very well, but there are tons of interesting articles and TH-cam videos that do a great job describing how Bernoulli's principle applies to sailing if you're curious.
Brilliant, thank you. Ive been trying to understand these boats whilst watching sail gp and just couldnt figure it out. Clear and concsie!
It’s a bit of a mind bender but glad it finally makes sense!!!
Very interesting. The Yacht is effectively being squeeze between the wind and the water. Amazing.
Yes that’s how I like to think of it!
I was conceptualising about how sandships would work in my worldbuilding project and this came to my recommendations. Thanks for the vid! very informative~
Thanks for watching - glad you liked it! Good luck with your project!
I thought Jordan Peterson was narrating this video 💀
LOL - I’m not sure if that’s good or bad!
@@SailingTipsCait means you have an opportunity for parody my friend.
@@northernmetalworker That could be my new schtick!
No, he called it a boat not a “boot”.
@@SailingTipsCawith some practice you could do big things!
I now understand a little bit more about what hydrofoils and dynamic keels do under water, and how it balances the sailboat to prevent it from keeling over and how it might drag, stall, or fail if sudden changes are applied to it.
As a SailGP enthusiast, I'm grateful
Glad it makes a bit more sense now! You’ve probably noticed that once the SailGP boats fall off their foils it takes a bit of work to get them back up there because they have to overcome the drag of the immersed hull. Amazing machines!
@@SailingTipsCa To me the boat falling off or getting on the foils was as intuitive as changing gears, or picking up speed in a bike to help keep it upright. What puzzles me is the things done by the flight controller, and the wing trimmer tandem the grinder/s because the adjustments done by these guys aren't easily shown and maybe a competitive secret.
@@SukacitaYeremia I understand the flight controller will be constantly adjusting the angle of attack of the foils to keep the boat at the desired foiling height based on the boat speed e.g. less speed more angle of attack and vice versa. The wing trimmer will be positioning the wing to power up or power down the boat based on the prevailing wind speed and direction, and in conjunction with the course being steered. Both the foils and the main are hydraulically controlled with pressure created by the grinders.
This was a very well made video. Thank you for being so clear and concise and not making a 10+ mins video 👍
Glad you enjoyed it! I’m a big fan of both watching and making shorter videos!!!
Thank you, excellent description and visualization. I learned a lot
Excellent - glad it made sense!!!
We call it creating your own wind (on low drag boats), thats why the appearent wind always comes from the front(and way stronger then the real one), even on reach or broad reach, but you cant do it downwind. You have to reach and jibe downwind.
Yes it doesn’t work going dead downwind as you noted!
When you tack the sail, how does the dagger board tack to change the direction of lift below?
Great question - it really depends on the boat. Some have asymmetric foils that they raise and lower at each tack. This is the most efficient solution hydrodynamically but involves more work for the crew and precise timing. Others have symmetric foils where lift is generated by altering the angle of attack, normally via the helm/rudder in most boats.
What a nice information! I have worldbuilding project and want to gain insight to how one can make Old Imperialism era sailing ships, so your video helped me. Thank you!
Glad it was helpful!
Great explanation! I just watched a race video and was wondering why they just had one foil in the water. Your video answered that question too.
Glad it was helpful - thanks for watching!
sailing is not an interest of mine, but your video caught my eye. thanks for that explanation :) i'm a land lubber but hydrofoil ships have always interested me. esp the USS Pegasus. it just seems like a no brainer to lift the hull out of the water. (thank you material science for developing such amazing composites :) ) but your lift explanation makes a lot of sense to this virtually virtual pilot :)
I’m glad it made senes and captured your interest! Note that boats that can plane on top of the water can also sail faster than the wind, but still not as fast as hydrofoilng boats that lift the hull out of the water. It’s all about lift vs. drag.
Fascinating and clear explanations. Thanks!
Glad you liked it!
Puck description is spot on well done Sir!
Glad it made sense!
So well explained and visually represented!
Thanks - glad you liked it!
It surprised me to hear Jordan Peterson! 😂
I don't know why the algorithm promoted this video but i am happy to have watched it! ⛵️
You’re not the first person to say that I sound like Jordan Peterson - glad you liked the video!!!
Nice video and demonstration.
Glad you enjoyed it!
Such a great explanation!
Glad you liked it!
Explanation via forces and vectors: Drag (force in N) in - opposite - wind direction, Lift (force in N) orthogonal to Drag. The vector of the resultant force is splitted other wise: into sailing direction and orthogonal direction. The force in the sailing direction moves the boat forward and the other one heels the boat sideward. The keel must be heavy to create the sufficient righting moment in order to prevent the capsize.
de.wikipedia.org/wiki/Physik_des_Segelns#/media/Datei:Wirkung_des_Windes_bei_Amwindkurs.svg
Nice diagram - thanks for sharing! Yes the sails generally create more heeling force than forward drive. Most boats use heavy lead keels to create righting moment and counter heeling, but some boats (e.g. multihulls) use floatation and the weight of the boat itself to counter heeling, while others (e.g. foiling boats) use hydrodynamic forces in conjunction with the weight of the boat.
Thank you for clearing my mind about this !
Glad you found it helpful!
great explanation of a complex concept! thanks
Glad you enjoyed it!
Brilliant explanation
Thanks - glad you liked it!
Interesting. I wonder if you can apply same principles in electromagnetic fields. Will the boat sail faster if the was 3 forces pushing it in a same manner? Is there an angle range for the most efficient thrust? Thank you
I think you could use this technique in any low-friction environment with opposing forces and the third dimension could be levitation which would result in very low drag/friction! I think the optimal angle is a function of the amount of drag/friction, whereby less drag enables tighter (i.e. more acute) angles and higher speeds, whereby more drag/friction requires larger angles but results in lower speeds. Think of it like gears in a car or bicycle!
Thank you, very amazing! These sail races are really fun to watch
I completely agree!
Thankyou
I can now understanding tacking a lot better.
Excellent!!!
This was very informative.
Thanks - glad you liked it!
I like that you used Trent Palmer's Freedom Fox!
I’m a closet aviation buff and fan of Trent Palmer’s! I once dreamed of owning a plane but boats are much “cheaper”…
@@SailingTipsCa Me too. I can’t get flying out of my head. I keep thinking somehow I can afford it. It’s so expensive! Trent must do well.
@@scottwooster4102 I think he does, apparently his bread and butter is filming driving scenes for car commercials. The other benefit of a boat is that your can camp on it, have a barbecue on it etc so there is more utility in many regards.
Very interesting thanks for the information
Glad you enjoyed it
Great explanation mate
Thanks - glad you liked it!
I would start off by explaining apparent wind , and then use vectors
Yes that’s a great idea - fast boats are almost always sailing upwind even when they’re sailing downwind!
Wow that was incredibly well explained
Thanks - glad you liked it!!!
Good video, but no love for Trent Palmer for the flight footage?
I love his channel and I’ve added a thanks to him in the video description!
Very good video and explanation. Thank you
Thanks - glad you liked it!
By a lot less drag than the Nina, Pinta, and Santa Maria....A LOT LESS !
Yes those boats did have a lot more drag…cool names though!
Your're talking to a guy that flew a Pheonix 18 on one hull most of it's time on the water at Santa Cruz, CA, @@SailingTipsCa
@@waltsnow1762 That sounds like a ton of fun!!!
excellent explanation.
Glad you liked it!
That was very informative. Thanks! Question: let’s say steam and combustion power was never invented. But these effects became known. Could practical cargo, passenger, and warships have been designed using these principles? Or would the lack of modern materials not allow these type of ships on a practical level?
Excellent question! Cargo, passenger and warships did all have sails at one time, with schooners being amongst the most advanced of these, but they were all still reliant upon the wind, which is inconvenient if you have to be somewhere at a given time and the wind isn’t blowing. I don’t think materials is a constraint these days, but schedules definitely are! Sails also generally require larger crews compared to motorized vessels which creates an economic constraint as well. Still it would be possible without motors!!!
1:47 l'd say that foil lift is more directed to the aft than to the bow.
Really - why do you say that? I understood lift to generally be perpendicular to and corresponding in magnitude to the curvature of the foil. Therefore with symmetric foils which most boats have the lift would be perpendicular or slightly forward of the centreline of the boat no? resources.system-analysis.cadence.com/blog/msa2022-exploring-the-aerodynamics-of-symmetrical-airfoil
I knew sails worked like airplane wings but always thought the lift of the sail "pulled" the boat. It did not occur to me that there was another foil underneath and the boats motion is the resultant of these lift vectors. Short and sweet vid.
Glad you found it helpful!
The air does pull the boat. The question is in what direction is the pull directed?
Long time since I've learned something this interesting!
Thank you for sharing it.
I was amazed.
Glad you enjoyed it!
Ty, wondered how that worked. Great explanation
Glad it made sense!
there's a crucial detail that should be noted. High performance class boats are able to go faster than true wind on up and downwind lines due to the design that allows the boats to manipulate apparent wind in an unconventional manner. The best example of this is when the AC72/75 is downwind, the trim is changed to an upwind mode as when it is travelling faster than the true wind, it's as if the wind is going backward! So technically a jibe is in actuality a tack
Yes it’s not uncommon for faster boats to be sailing “upwind” all the time! Even my “slow” F-82R trimaran can “bend” the apparent wind forward by up to 90 degrees so we’re always sailing with the apparent wind forward of the beam even under spinnaker!
This is the part that breaks my brain (old school sailor). When AC boats are jibing downwind I just can't comprehend what is happening. Is there a point where they switch from tacking to jibing if the wind drops?
@@tmhudg The term “tack” is typically defined by turning the bow of the boat through the eye of the wind, whereby a “gybe” is turning the stern of the boat through the eye of the wind. With an AC boat the key question then becomes whether this definition is based on the true wind or the apparent wind. Turning the stern of an AC boat through the eye of the true wind may technically still be a gybe, but it will certainly feel like and be executed like a tack because the apparent wind in the faces of the sailors and on the sails from ahead will generally be stronger than the true wind from behind. Those who have sailed them (not me) can probably say for sure, but given their efficiency I don’t expect there to be any conditions where they would choose to sail with the apparent wind aft of the beam, so a gybe would probably always feel like a tack.
@@SailingTipsCa That makes sense but there are things that still are hard to grasp. Like when rounding an upwind mark, what changes are made to the sails when going from sailing "upwind" to sailing "downwind"? I get that the apparent wind is still coming over the bow(ish) but it certainly lessens as they turn right? Are they trimming sails differently?
In lighter wind (and therefore slower boat speed) is there a point where, when turning to go downwind, the apparent wind is aft of the beam? If so, do they then have to do "normal" gybes at that point?
@@tmhudg Great questions! The apparent wind angle will be the tightest (as measured from the centreline of the boat) on the upwind leg and will be slightly lower on the downwind leg. So just like any boat the sails will be fully sheeted in as tight as possible for the upwind leg, and eased as the boat rounds the windward mark, but not by much, something on the order of 20 degrees (again as measured from the centreline of the boat). So close-hauled upwind and close reaching downwind.
On my boat, which is much slower than an AC boat but still sails faster than the wind, it is pretty much always fastest to sail with the apparent wind forward of the beam, even downwind in light conditions. This is because the lift created by the sails is always the greatest when you can get the wind flowing across them like an airplane wing, and the extra distance sailed is easily compensated for by the increased speed.
0:48 I'd recognize the Freedom Fox anywhere...
Yes and looking forward to seeing Trent’s new plane in the air!!!
So the keel is basically resisting the force of the wind on the sails?
Exactly - without it the boat would slide sideways!
I was always curious about kite surfing, thanks for the video!
The principles of opposing forces are similar albeit with different equipment!
Is the hydrofoil necessary to achieve faster than the wind sailing?
No it’s not necessary to use a hydrofoil to sail faster than the wind and several other non-foiling boats like dinghies, multihulls and planing sport boats can also sail faster than the wind with just vertically-oriented daggerboards and rudders, albeit generally not as fast as hydrofoils. That said the around the world sailing record is still held by a non-hydrofoil multihull. You just need a sufficient amount of lift from the sails and underwater appendages versus the drag in the system.
*For the curious:*
Blunt Body 2d: Cd = 1.0 ~ 2.0
High Lift Airfoil: Clmax = 2.0 ~ 4.0 (4π theoretical limit)
Thanks for sharing!!!
awesome explanation...
Glad you liked it!
At last! Someone who explains method WITH CLARITY! Those who pretend to know, tap the side of their nose.
Thank you, ST - your two rod analogy (squeezing the boat faster than wind-speed) is now my firm imaginary model.
Thanks - glad it makes sense!!! You also don’t need lifting foils but just lift versus drag ratios that allow the “rods” to be at a very acute angle!
You don't need to invoke Bernoulli / foil lift principles to explain why a boat can travel faster than wind.
You even showed the effect with the disc, and you had no foil present. It's just vectors and "sliding surfaces" or an angle of attack.
Yes in retrospect showing lifting foils makes the video slightly more confusing than it might have been with another boat with the high lift versus drag ratios like a planing dinghy, sport monohull, or multihull. Otherwise you’re right it’s about vectors.
There is a blend of two explanations merged in to one. Daggerboard and foil.
These are different things although both under the boat.
A foil has nothing to do what a daggerboard does and vica versa.
Foil lifts the boat out of the water so drag is strongly reduced to get more apparent wind
Daggerboard is a vertical device which has, usually, not the shape of wing. The boat has to go in both directions. It prevents the boat going sideways
People tend to think only of lifting foils with the term “foil” but daggerboards, rudders, and lifting foils are all technically lift-generating foils that have different orientations and different jobs under the water.
Thanks much. Good explanation, as usual.
Thanks so much!
Seems some what similar to how a surfer can often go faster than the wave they are riding.
Possibly, but I think that’s also a factor of the waves slowing down in shallow water while at the same time getting steeper which provides more of a “slope” for the surfer to slide down and outrun them!
Vectors and mechanical advantage.
How does a block-and-tackle gain so much advantage?
How does a crowbar gain so much purchase?
How does a wind turbine, turning a 15 RPM turn a generator of 1,500 RPM?
Yes and all of these concepts are also used throughout the boat for various control purposes such as sheets, winches…
wow, holy cow, i learned something new today.
That’s great - exactly what this video is for!!!
You also have apparent wind and true wind. It makes the wind angle shift and wi d speed increase .I think there a lot of factors
Yes there are indeed a lot of factors! I mention how apparent wind builds and “bends” forward at around 2:15 of the video, and keeps building as the boat accelerates until the lift equals the drag.
While early ships can't really compare to what we have today, they were certainly more advanced than 'throw up a sail like a big parachute.'
Yes they could reach a bit but really couldn’t make good progress upwind or away from a lee shore like.a modern boat. Still amazing pieces of work!
You say that this would be impossible to do without modern materials. Could you not get a similar, though lessened effect with traditional materials? What is the most technologically primitive (in terms of construction) you could get to make a boat that utilizes this principle?
Yes there are some planing dinghy designs that can be built from very thin marine plywood (e.g. Fireball) and still sail slightly faster than the wind on certain points of sail, but not 2-3 times faster on all points of sail like a carbon fibre full foiling design. You can also build some Farrier trimarans using cedar strip construction that will sail slightly faster than the wind. In both cases you will still need some composite components to hold things together e.g. glass fibre, epoxy. Is this what you meant?
@ Kind of, yeah. Imagining if one was thrown back in time, or survived after a nuclear apocalypse, could one use this tech, without today’s industry. Setting up the keel wing doesn’t seem too out of the realm of possibility, so would be a matter of getting the sail rigged right, I think.
@@Skyblade12 You could definitely build a decent-performing boat from wood, but then the limitation becomes what kind of glue you have access to and whether you have plywood or are milling your own trees.
Newton: “Every Action produces an equal and opposite opposite reaction”
Sailing: “Some actions produce a 90°ish and faster reaction”
I think if you break all the forces down into their vector components Newton is still right, but there are a lot of forces which muddies the waters!
Best explanation ever :D
Thanks so much!!!
Did you get that clip with permission from Trent Palmer?
I incorporated Trent’s clip into this video under fair use and let him know as a courtesy.
Have you heard about people who have sailed into the earth via the north pole? Many books and stories on sailors who have sailed into the earth via the north or south pole to the agartha network of cities. Amazing video about sailing and the wind.
I am definitely not familiar so something I will need to look into!
thanks for the content)
Glad you liked it!
Is there a difference in speed when going upwind vs downwind in the same conditions (edit: angled to the wind for max speed)? Also a vector question. Mostly it's rhetorical, because I'm sure it differs depending on the boat, but mine is a sailing dinghy with a cat rig (edit: not a keel boat, but let's pretend it is). I'm wondering if the goal is forward motion would you end up at the same place at the same time in a dead run versus a broad reach. Obviously upwind has no corollary (edit: actually it does, would you end up at the same place at the same time in a close haul vs the speed of the wind?).
Good questions! Yes there is generally a difference in speed upwind vs. downwind relative to the true wind, and that difference depends on the boat. In my boat I max out at around 12 knots of boat speed when sailing as high as possible into the true wind, but can sail at 20+ knots off the wind.
For all boats the fastest way upwind is tacking through 90 degrees, and for fast boats the fastest way downwind is also gybing through 90 degrees relative to the true wind, as this keeps the apparent wind forward of the beam which keeps the sails working as wings and is much faster than sailing dead downwind.
When sailing dead downwind you can really only go 50-60% of the true wind speed, say 5-6 knots of boat speed in 10 knots of wind. But gybing through 90 degrees downwind my boat could go 12 knots in 10 knots of wind, so twice as fast, but only sailing 1.4 times the distance, so velocity made good (VMG) towards the finish is better even though we're sailing further.
Assuming the same apparent wind angle, the max. downwind VMG is 1 true wind speed greater than the max. upwind VMG. But that is only valid for very efficient sail craft like those foiling boats, or ice boats.
There is type a plot called a speed polar that gives the speed of the boat for all directions relative to the true wind. E.g. see here www.google.com/search?q=sailing+speed+polar&tbm=isch
Offwind (when the dot, a.k.a. scalar, product of the boat's velocity vector with the true wind velocity is positive), for some boats the downwind component of the boat's velocity vector is greater than the true wind's velocity vector. So those boats, with velocity vectors 10-30° off the true wind vector, could beat a balloon blown from an upwind mark to a mark directly downwind, even though those boats would go out to the side with respect to the straight downwind course, gybe, and come back to the downwind mark.
great video
Thanks - glad you liked it!
Hi. Very good vid ! I have a question - what is "needed" to go faster than wind ( is your Tri able to do so ) ? Would be very interesting video to create - It could be called: " What is needed to go faster than wind". Wing mast ? Power to weight ratio ( Sail area to displacement ) equal to ... ?
Good question and video suggestion! Somebody once told me that everything in sailing comes down to lift versus efficiency and I think that applies here too.
Our F-82R trimaran can sail at around 1.2 times the true wind speed, but it has no lifting foils and relies entirely on floatation for righting moment.
Off the top of my head I think that what you "need" to sail faster than the wind is:
1) A powerful sail plan - most boats that can sail faster than the wind have huge flat-top mains, a rotating mast also definitely helps here
2) A hull that is not constrained by displacement hull speed "rules" (i.e. 1.34 x sqrt(waterline length)) so either a planing hull for a monohull, or a multihull with long skinny hulls and a length to width ratio of greater than 8:1, or lifting foils
3) Enough righting moment to keep the mast upright without impacting 2) above, so for a monohull a canting keel definitely helps
Interestingly I have a friend with a Cheetah 30 sport boat, which has a very similar sail plan to our F-82R, a planing hull, and about the same boat weight, but the Cheetah is much harder to sail faster than the wind because we run out of righting moment and get knocked over as the apparent wind comes forward. In fact the F-82R has about five times the righting moment of the Cheetah and as a result the F-82R rates about 30 seconds per mile faster. The F-82R also has a rotating mast but I think the righting moment is the biggest contributor.
@@SailingTipsCa Thank You!
I have a 24 ft monohull with a Dacron sail. While it is light and efficient it has no foils or Alma’s ( outrigger multiple hull sponsons). I frequently sail at wind speed + 2 knots. The trick downwind is to not sail exactly downwind but off the wind in order to create the draft effect on the sails. That’s why you see sailboats jibing downwind to get to a point that is directly downwind from the boat. Longer distance but much faster speed.
Light weight and with it low drag. I had a 24 mtr cat before with 9 tons and 1 to 19 ration waterline. Same thing without foils or planing.
I like how in search of the "fastest boat" humanity step by step erased traditional hulled boat until the absolute, the platonic ideal of the fastest boat, looks nothing like traditional boat.
1) narrow hulls offer less resistance, lets make it as narrow as possible.
2) but the narrow hulls have stability problems, let's double the hulls.
3) fuck it, lets triple them while we're at it.
4) aaand to reduce resistance even further, let's completely lift the hulls out of the water.
Congrats, you have modern racing trimaran "flying" on wings.
Yes it’s been interesting to watch the evolution of sailing “craft”!!!
Great video
Glad you enjoyed it!
Fascinating One of life's little mysteries solved!
Excellent!!!
My prediction before watching the video:
The forces must be equal, but a lot of slower air in a massive sail can equal the force of some small vanes going forward quite fast.
Pretty much…and maximizing lift while minimizing drag!
I would love to learn what the most well designed ship would look like, if it had to use materials available in the 17th century, and also carry cannons.
That would be very interesting, kind of like that test they did with modern sailors recreating Shackleton’s escape from Antarctica using period materials, clothing, and food!
I think over the 100s of years of sail ship evolution, they pretty much nailed it down what worked and what didn't. Ships wouldn't look much different, imo.
@@after_midnight9592 Except that in the 17th century they didn’t yet understand how to create lift with wings - that came later!
imagine what and old sailing ship captain would think if he came to the future and saw what a modern sailing vessel was capable of. he'd have us all burned at the stake for sorcery XD admiral nelson's HMS Victory plodding along at 9 knots and then an america's cup catamaran zips past him at 80 knots with its hull floating out of the water going UPWIND. their brains would melt trying to make sense of it.
I know - even 30 years ago it would have been unbelievable!!!
I'd say the Captain would have understood the basic principles, but also figured out that our ships are far stronger and lighter than anything he had to work with. He would also have recognized that a ship designed to carry over 100 cannons plus their ammunition along with food and water for several weeks on high seas along with onboard repairs out of carried and local materials would be a very different design than a vessel optimized for pure speed over a matter of hours.
The Captain would have been amazed at it and definitely want to take a tour of the catamaran, but he would have understood the basic principles.
@@toddkes5890 you're completely clueless. HMS victory was the cutting edge of naval technology in nelson's time, and it was powered by parachute sails. if he intuitively understood how airfoils and hydrofoiling worked he'd have been a genius on the level of newton. sailing upwind is so counterintuitive it took the human race five thousand years to figure out. NO ONE is gonna say 'that makes sense' just by eyeballing it.
@@toddkes5890 Those >100 cannons and their ammunition is going weigh a lot so hopefully anybody with access to high-tech sailing materials is also going to have access to high-tech weapons that are a bit lighter!
@@oldfrend He didn't fully understand the airfoils and hydrofoils, but the Lateen sail that allowed the airfoil effect of sailing upwind was developed in 900 AD. That is over 800 years before HMS Victory was laid down.
He would not have known the mathematical models to get optimal performance, but as a Captain of a warship in a nation that relied on the skill of its ship Captains, he would have understood the basics.
Wtf I never knew. This is very interesting.
I think it’s super interesting too!!!
Thank you, finally someone, who can explain it to a moron like me. I think i get it now. Thx and have fun!
LOL glad it finally made sense!!!
Interesting. If this is correct and made a static situation we could generate power without windmills?
I think you still need kinetic energy turned into electricity by some motion.
Yes a static situation could generate lots of force but to generate electricity you generally need to spin a magnet inside a coil of wires (or something similar) so you need the motion!
So wait ... If the foils are lifting the boat, most of the foil ends up being above water so how does it then provide "lift" against the sails....
Good question - there needs to be enough of the vertical foil component left in the water to counteract the force of the sails and drive the boat forward, so teams need to be very careful to lift the hull out of the water but not lift the boat too high so they loose the lateral thrust vector.
I fully understand how sailing faster then the winds works, but your way with the two rods are the most random way of explaining it
Another analogy is “shooting” a watermelon seed from between your fingers by squeezing it…but most watermelons don’t come with seeds anymore!
My understanding is water is essentially incompressible, especially under normal conditions. It's why depth charges work. So how do you have areas of high (compressed water) and low pressure (expanded water) under the keel? Especially as the (compressive??) forces involved must be tiny. 1m.38s
"Essentially incompressible" means that the volume doesn't change much, despite high pressure differences, not that there are no pressure differences. The air that interacts with the sail is also "essentially incompressible" at those speeds (way below Mach 0.3).
Yes incompressibility relates to water not changing volume much under different pressures, not that it can’t be under high or low pressure! It’s the low pressure that substantially lowers the boiling point to be at or near the sea temperature. Check out this video on Vestas Sailrocket for more info on that! How Did Vestas Sailrocket 2 Smash the Sailing Speed Record?!?! th-cam.com/video/K3m06731BQY/w-d-xo.html
You can definitely change the pressure of water in sailing and marine applications. Just look into propeller-driven cavitation if you don't believe me.
I think this is a far better treatment than Veritasium's one (where he didn't even understand the principle himself, did an actual experiment, and his best explanation was to quote the mathematics).
Thanks so much! It’s the best model I could come up with to help people visualize how the resultant force vectors drive the boat forward!
The simplest physics explanation is that momentum is always conserved. Mass 1 x velocity 1 = mass 2 x velocity 2. Clearly it is possible for v1 to be different than v2.
Yes that is a very simple physics explanation! How do you take into account lift versus drag?
Fast boats are generally pretty light and slow down fairly quickly when the wind dies!
@@stingtheweimaraner that is where efficiency comes in, specifically:
Above the water, the limit is set by the efficiency of the sail diverting the side (cross-boat-velocity) component, which is constant, of the apparent wind relative to the increasing drag of the anti-boat-velocity, which increases with increasing boat speed. Key points: the only thing the sail has to work with is the side component of the wind vector, and that does not change with boatspeed; what does change is the angle of the wind on the sail i.e. apparent wind moves forward with increasing boatspeed, and that affects the efficiency with which the sails operate.
Below the water, basically the same thing: the side force, and therefore the leeway velocity, is more or less constant; the drag of the underwater surface increases with boat speed.
So the ability of the sail to generate forward force, i.e. its efficiency, decreases with increasing boatspeed as the apparent wind goes forward, while the drag forces increase with increasing boatspeed. The speed limit is reached when the forces are balanced.
Got it, magic.
I know - it really seems like it!
I thought it was all about apparent wind. I used to have a small land yacht that would “sail” much faster than actual wind speed. No second foil there
Yes it all really comes down to lift (from the sails) versus drag (from the sails and the surface the “boat” is “sailing” on. Ice boats and wheeled land yachts (e.g. blo-karts) can easily sail faster than the wind because there is so little drag with the surface they are on. They use the same principles in this video but with one rod stationary and representing their lateral grip on the surface. It’s a bit harder on liquid water because there is much more drag. Lifting foils help reduce drag, but they are not necessary for all boats as there are also many other types of boats (e.g. planing dinghies, multihulls) that can still sail faster than the wind without lifting foils.
Does the underwater daggerboard kill sea life? I mean can like a whale or porpoise or fish or sea turtle hear the sailboat coming and move out of the way or are they just sliced open? Is there anything mankind does that doesn't hurt nature?
It’s certainly possible that an underwater daggerboard could harm sea life, however they do tend to make quite a bit of underwater noise which gives most sea life ample time to get out of the way.
Is it rue that the water left behind the trailing edge of the foils on the AC cats gets as high as boiling temperature? Seems hard to believe, I know, but I read that somewhere a while ago.
You probably mean cavitation. The water is not boiling because of high temperature, but bubbles are forming because the pressure is reduced by the foils.
Yes it’s more a matter of the boiling temperature of water dripping towards sea temperature due to the low pressure, and not the water being heated. I show a clip of it in this video: How Did Vestas Sailrocket 2 Smash the Sailing Speed Record?!?! th-cam.com/video/K3m06731BQY/w-d-xo.html
@@albatrosssoaring1487 I recall that they said boiling temp.
@@joeblow1942 Yes, boiling temperature is pressure dependent. If you reduce pressure enough, water can form bubbles at the temperature of the sea. Look up "cavitation".
Thanks
Welcome!
This is only true when the boat is not travelling in the same direction as true wind right? Can a boat travel faster than true wind in the same direction as true wind? Assuming the wind is constant
Fast boats typically tack through 90 degrees going upwind and also gybe through 90 degrees going downwind as that’s much faster than sailing dead downwind! In other words the are typically sailing across the true wind to some degree although the apparent wind they are experiencing due to their speed is always from ahead.
@@SailingTipsCa So for example there is an island 35km north from my boat. There is a wind heading directly north at 35km/h. If I travel exactly straight north in the exact same direction as the wind, it would take me 1 hour to get to the island? But if I zigzagged back and forth I could get there in faster than 1 hour?
@@mcdonaldslover52 Sailing dead downwind is not very efficient because you effectively “outrun” the wind so you’d be lucky to get 50% of the wind speed as boat speed so it will take you about two hours. On the other hand if you gybe back and forth in a zigzag you’ll travel about 1.4 times further, but you’ll also be able to achieve more than twice the speed so should be able to make it in about an hour in a fast boat.
@@mcdonaldslover52 yes, depending on the boat. Also, it is possible to build a land device (not a boat, but something with wheels) that can go DDWFTTW -- Directly Downwind Faster Than The Wind. It's been built and proven.
That you Jordan peterson, very helpful
LOL I’ll tell you what’s wrong with it in the next video!
They make their own wind out of true wind. Its called "apparent" wind. I first noticed this in my Hobie 16 when both of us were on the wire. In a 15 mph wind my Dad's under powered runabout couldn't catch us even though he could reach 25 mph easily. He couldn't believe that we left him well behind. We were on a broad reach the fastest point of sail.
That must have been so much fun to outrun dad like that!!!
From my understanding, foils don't produce propelling forces at all. They lift up the boat vertically to reduce drag and stabilize it in the water so that the boat doesn't sweep sideways.
I totally did not understand the physics of the foil's forces shown in your examples. 🤷♂️
The word “foil” is a general term for wing which can do multiple things: 1) a rudder is a foil that steers the boat 2) a daggerboard or keel is a foil that opposes the force of the sails to drive the boat forward 3) a lifting foil raises the hull out of the water to reduce friction. An efficient boat can still sail slightly faster than the wind with only the first two, but to sail at multiple times the wind speed you also need the third to lift the hull out of the water. The foil at 2:32 of the video provides lift in both the vertical and horizontal planes to carry out jobs 2) and 3) with a single foil. Does this help?
@@SailingTipsCa 1:50 - Author. You misunderstand, therefore, you draw the balance of power incorrectly.
Your 'Foil lift' propels the boat forward. This is nonsense.
In fact, this force is always opposite and equal in magnitude to 'Sail lift'...
@@MikleM1 Yes i did say the foils and sails generate lift in opposite directions but the drawing could definitely be better in that regard!
@@MikleM1 "2) a daggerboard or keel is a foil that opposes the force of the sails to drive the boat forward" is correct. The sails propel the boat forward, but won't do so without the opposing action of the keel or foil. Note that he is saying that the sails drive the boat forward.
@Timo Rieseler The video shows an "L" shaped foil that has a vertical, lifting part of the foil (which is horizontally oriented) to raise the boat out of the water and a horizontal part of the foil (which is vertically oriented) to counteract the side (component of) force from the sail. A single foil does two things: vertical and horizontal lift.
Horizontal lift is always needed in a sailboat in order to counter the side force of the sail.
It's also possible to have a foil that only resists the side component of the sail force. That's a daggerboard or regular keel. They have only a vertical member.
There are several possible arrangements of foils, including ones placed diagonally that also provide both vertical and horizontal lift components from a single straight foil, curved or C foils, "J" shaped, "L" shaped, etc.