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  @renatoboro1942 ай бұрын

  Good morning. Do you know somewhere where I could download the project to sew a size 5.7 sail in the classic windsurfing style one design windsurfer

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  @HamCubes3 ай бұрын

  We learned a lot! Thank you, Julian! 🙏

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  @vicferrmat44924 ай бұрын

  Thanks for your valuable help.

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  @TheHeatherTube4 ай бұрын

  I want to know what it is called when you lower the sail and tie it. It's called trim. That's not what you are saying.

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  @howarthsailing4 ай бұрын

  When you lower the sail part of the way and tie it, it's called "Reefing". Not covered in my presentation here but definitely a valid strategy for depowering your sail.

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  @TheHeatherTube4 ай бұрын

  @@howarthsailing Thank you my Dad and I did it a lot but I couldn't remember what he called it. Thank you for reading my comment and answering. Hats off to you Sir!

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  @TheHeatherTube4 ай бұрын

  I kept looking up trimming but I knew that wasn't it. I knew that wasn't what it was called. Thank you for understanding what I meant. So cool and Happy Sailing!

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  @TheHeatherTube4 ай бұрын

  The only part I disagree with is the depowering. It's the short shift and the extra trim to go even faster. But safer.

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  @richhasideas4 ай бұрын

  Thank you for sharing your knowledge. One day, I hope to circumnavigate the globe, and this is precisely the type of information I am looking for. As a commercially rated pilot, much of the information in this video is similar to what I have learned in aviation. Of course, some of the terminology is specific to sailing, but the physics principles of an airfoil remain constant. I'm really looking forward to watching more of your videos.

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  @savedbygodsgrace16224 ай бұрын

  “Sailing Theory” means they’re not going to give you the facts about how a sail boat works.

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  @sailslife8 ай бұрын

  Thank you for your video! I learned quite a lot and refined some of my knowledge. I don't quite agree with "Boats Experience just Enough Leeway", though. My students often try to accelerate the boat sailing close hauled with no speed after setting sails or a bad tack. What this leads to if that the boat is actually going sideways a lot. As I understand it, the first second that the wind fills sails in such a situation and the water starts flowing, the direction of it's flow should be opposite to the direction of "E", combined forces of the sail. And even if the sail is trimmed perfectly, the angle of attack on foils is to big, so they stall. A lot of drag is generated, which results in either the boat heeling a lot, or drifting sideways if hiked. Also, the rudder is useless in this situation, so the boat usually can't be controlled. It can head up or bear away, but it's not relevant in my question. What happens underwater, when sails seem to be trimmed perfectly and the boat points very well, but drifts sideways? Of corse, as you gain any speed angle of attack changes drastically and foils lift starts to help in acceleration, and then the boat flies as you said - easy in going forward and really bad in going sideways. But I don't like seeing my students crashing into each other on a start line because of this misunderstanding :) I would be really greateful if you could clarify. Thank you!

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  @howarthsailing8 ай бұрын

  Hi Ivan. I think you're spot on. I'd add a couple of points to clarify this aging video and its explanations: 1. My use of the expression "Just enough leeway" doesn't imply that the amount of leeway your boat experiences is desirable or even beneficial, just that it is this missing piece of the vector equation. Maybe I could have used different language for that part. 2. My description really only applies once the boat is moving and once the sails are trimmed within a reasonable range for the direction of the wind. Starting from a stop is sort-of outside the scope of this video. You might want to give this article a read: gentrysailing.com/pdf-theory/Origins-of-Lift.pdf

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  @FernandoLXIX8 ай бұрын

  Awesome

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  @brianking53619 ай бұрын

  Hi JH, I believe the impact of current to a sailboat speed and direction is not absolute, or 1 to 1. In otherwords, I don't think you can just add up the combined speed and directions to determine a new vessel speed and direction, like you can in a powerboat. When making these calculations in a powerboat we assume a constant amount of power is being applied at the throttle, rpms. But in a sailboat the "rpms" from the wind increase and decrease relative to current, but are constant relative to the ground. Assuming for a second the sailboat is attached only to the wind and not to the water, the boats speed and direction overground would not change at all regardless of the current. The best example I can give is a sailboat sailing directly down wind at 5 knots in 8 knots of wind, that suddenly comes upon 5 knots of current going in the same direction of the boat is not going to being going 10 knots over ground. It's going to struggle getting over 5 knots overground because it's going to run out of power, "rpms" from the wind. Exaggerate the numbers and it becomes more obvious. Like 5 knots of wind and 20 knots of current. Please help me with this, because you're the only sailor I've found online that really understands this stuff and can explain it in a way that is digestible. Thanks!

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  @howarthsailing9 ай бұрын

  You're onto something here, but it's more complicated than that because the direction the boat is travelling relative to the wind will really influence how fast it can travel. In fact, the speed of the current will be a part of a velocity vector addition to determine the apparent wind speed and direction as well. I think the examples in this video will hold true for a boat that travels at approximately its hull speed, in a situation where the wind strength is much greater than the current. Otherwise, you're right, more analysis is necessary.

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  @RanamKazziha10 ай бұрын

  Great Video to explain sailboat balance!

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  @AdriaanJABreukel11 ай бұрын

  Very, very good.

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  @alexbellesia967611 ай бұрын

  Thank you, excellent demonstration.

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  @colorocko1 Жыл бұрын

  That was absolutely fantastic, thank you!

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  @brianking5361 Жыл бұрын

  It seems like CLR should point forward not aft. It appears CE and CLR are exact opposites at 18:09 which means the boat would not move if CE and CLR were at same spot fore and aft or the boat would just turn in circles if they were separated.

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  @alans172 Жыл бұрын

  15:00 You can't do experiments on simulations, they simply regurgitate the ideas of the designer. Develop a hypothesis and then test it in reality. Testing on a model that incorporates the hypothesis is the ultimate circular argument.

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  @alans172 Жыл бұрын

  8:59 No, it doesn't. It either goes over or under. Check Babinsky's video. Sometimes the smoke arriving at the so-called stagnation point flicks over the top and sometimes it flicks under the bottom. It never stops.

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  @howarthsailing Жыл бұрын

  As I understand it, there's an infinitesimaly small amount that does stagnate but it really doesn't matter though, the dashed line helps us understand where the air divides to pass on each side of the sail. We are not analyzing a sail design here, we are just developing a visualization of how the air is moving over a sail and being careful to avoid the commonly used, incorrect explanations of longer and shorter distances.

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  @alans172 Жыл бұрын

  ​@@howarthsailing If it "really doesn't matter", then why introduce it at all? You are just confusing your readers by harping on about it. Why don't you just say that: "It is the point where the air divides...." and save yourself and your readers the hassle of struggling with the myth of the stagnation point. It was introduced by misguided mathematicians who needed to seed their PDEs in order to get some sort of correlation with nature.

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  @howarthsailing Жыл бұрын

  @Alan Smith Hardly harping, you're commenting on a video I made in 2018 where I explain as clearly as I can, the flow over a sail, visualized. There's plenty of literature to support the stagnation streamline, and stagnation point, I am not the author of those works. Feel free to link to the content you prefer. Please take your argument somewhere else.

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  @RubiKeys Жыл бұрын

  that´s gold my man

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  @cordvision Жыл бұрын

  Thanks for the informative videos! Any chance you could share what drawing app you are using?

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  @howarthsailing Жыл бұрын

  The old videos were recorded on my Samsung Galaxy Note 10.4 tablet and the stock SNote app was what I used. I haven't found anything that I like for annotation on my newer Microsoft surface pro.

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  @cordvision Жыл бұрын

  @@howarthsailing Thanks!!!

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  @givemerandom8617 Жыл бұрын

  You have a new follower bud

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  @algotrader8677 Жыл бұрын

  Excellent ! Love the combination of theory and practice explained visually in simple terms.

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  @robdarby1426 Жыл бұрын

  Hi Julian, I'm trying to solve a weather helm issue in a Flying Fifteen, which is an early Classic fleet boat so doesn't have a particular set of dimensions, the Classic boats all seem to be dimensioned and rig a little differently. The mast foot has 3 positions, the forward and aft positions being about +/-40mm from the central position. I currently have the mast foot in the forward most position and I'm still experiencing weather helm. Previously I extended the shrouds to get the mast rake as far forward as possible. This did produce a neutral helm, however other aspects of the rig were stupid, the boat looked awful with the boom climbing to aft and the gib clew way above the deck. So I have now reverted to a more normal geometry. I believe I cannot sensibly get the CE further forward than the current set up. Neither is it an easy task to move the keel on a Flying Fifteen, well pretty much impossible! I am wondering whether the rudder itself may not balanced. I'm not sure this is a thing in sailboats (but I believe it is in power boats). The Flying Fifteen rudder is very raked backward with the pivot point close to the top leading corner. This suggests to me there is potential that the rudder itself could have a CLR to aft of the rudder pivot point. If so, this would effectively make the rudder bear down and produce a weather helm effect on the tiller, the tiller being on the opposite side of the rudder pivot point. Does this make any theoretical sense?

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  @howarthsailing Жыл бұрын

  Kind of a complex issue but here are some thoughts. 1. When you move the mast step backwards, does this rake the rig forward? Usually the mast but adjustment is for inducing some pretend, or for changing g the rake, not for actually moving the whole.rige forward or backwards. 2. Sure it's difficult to move the keel, but this is some thing that high performance keel keelboat sailors do. They have a boat shop 'fair' the keel and at the same time, build up material at the front and shave off material at the back. Probably not your go-to solution, but a possibility. 3. How bad is the weather helm? It's typical to have some weather helm with the sails trimmed in hard, especially when it's windy, when the boat is heeling, etc. The trick then is to use sail controls to depower or ease the main to keep the boat "on its feet".

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  @paulsardar8138 Жыл бұрын

  Great video

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  @DavidHarbinson Жыл бұрын

  Julian, I have just discovered your tutorials on Utube. I am reasonably new to sailing so on a big learning curve. Your video on Sail Trimming Separation and stall is excellent. Really starting to understand what is happening with tell tales, why and what corrective action you need to take. Really appreciated thanks so much.

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  @rushellrousseau9197 Жыл бұрын

  Pure excellent these explanations. I've been sailing for almost 20 years and I've never received this information as clearly as I have looking at your videos.

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  @rushellrousseau9197 Жыл бұрын

  This is excellent!

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  @ketch_up Жыл бұрын

  It would be helpful to go over the when boats meet scenarios in a way that specifically focuses on upwind boats meeting downwind boats. I know it's "the same", but it sure doesn't feel the same.

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  @mikecritchlow1114 Жыл бұрын

  Could you explain how the underwater slipstream affects how the boat holds it's course? For instance, on the Lee side of the hull/fin the water is experiencing high pressure and naturally the windward underwater side of the hull and fin are experiencing low pressure. The opposite of what is happening to the mast and sails.

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  @howarthsailing Жыл бұрын

  I think that the other video I have called "Sailing Theory Tutorials - Forces on Sails and Foils" goes through this. Basically, the hull, keel (or centerboard as the case may be) and rudder have a flow over them, and because the boat makes a small amount of leeway as it travels through the water, there is a small angle of attack between the foils and the flow, this results in lift being generated in a direction that opposes the force of the sails.

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  @mikecritchlow1114 Жыл бұрын

  @@howarthsailing what effect will that have on the rudder?

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  @howarthsailing Жыл бұрын

  @@mikecritchlow1114 I don't think of it as having an effect on the rudder, more that the rudder takes some of the resistance forces, which should factor into where you consider the CLR to be. An interesting point though, is that you can stall your rudder by steering too hard, essentially, creating too large of an angle of attack at the rudder and causing flow to detach.

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  @mikecritchlow1114 Жыл бұрын

  @@howarthsailing HS... as I see it, the streamline from the hull and fin will have a sideways effect on the rudder inducing a turn downstream... hope that makes sense. i.e. if the boat is heeling to port, the slip stream will curve up and push against the port side of the rudder causing the boat to turn to port, or lee helm. This in turn will require the helmsman to have to keep adjusting to starboard if he/she wants to stay close hauled.

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  @howarthsailing Жыл бұрын

  @@mikecritchlow1114 I'd say that's possible. Most often the helm is out of balance in the other direction though, because the mainsail is often overpowering and the CE is roo far aft, so I think you'll find most helms people are used to having to fight to bear off.

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  @mikecritchlow1114 Жыл бұрын

  How does mast rake affect the C/E?

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  @howarthsailing Жыл бұрын

  If you rake the mast forward, the CE moves forward. If you rake the mast aft, the CE moves aft.

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  @mikecritchlow1114 Жыл бұрын

  The centre of lateral resistance is also affected be the underwater profile of the hull, not just the keel. The underwater profile of the hull changes as the boat heels.

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  @howarthsailing Жыл бұрын

  Absolutely, we discussed this at length is some of the deleted comments years ago. The shape of different hulls affects the location of the CLR and heeling (side to side) or even pitching the boat (fore and aft) can also move the CLR around.

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  @martygingras8683 Жыл бұрын

  Very nicely done.

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  @martygingras8683 Жыл бұрын

  Exceptionally good explanations.

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  @martygingras8683 Жыл бұрын

  Try adding shorter telltales that are much closer to the jib's luff, like shown in Photo 2 here: gentrysailing.com/pdf-magazines/9-Achieving-Proper-Balance.pdf Also Figures #2 and #3 here: gentrysailing.com/pdf-magazines/10-Sailing-to-Windward.pdf These telltales are much better because they warn of impending luff and stall rather than signal that luff and stall has happened.

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  @howarthsailing Жыл бұрын

  I am a fan of the Gentry articles.

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  @kenmarment4021 Жыл бұрын

  Can we measure the force created by the sail by measuring the tension on the sheet with say a force meter or a simple digital scale.? Could this single measurement assist triming of the sail. Much like a the resulting speed increase or decrease with triming the sail for max speed?

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  @howarthsailing Жыл бұрын

  You can certainly get a sense of how much load there is on the sheets, and relate it to the force on the sails, but you have to remember that as you sheet in and out the magnitude and the direction of the forces on the sails changes. The farther you sheet in, the greater the sideways, heeling, component of the force will be, so you can't say that more load in the sheet will equate directly to more thrust force driving you forward.

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  @gnocchi.artyst2 жыл бұрын

  Great examples and explanations. Thank you!

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  @roosterbooster62382 жыл бұрын

  Excessive healing

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  @chriskaminski46422 жыл бұрын

  I do have a problem with understanding your conclusion. Perhaps you can clarify it for me and others, please! The problem is that you are referring to Lee Helm and Weather Helm on your drawings without considering that both of the boats are on opposite tacks! Therefore your conclusion on the right drawing is wrong as it is Leeward heel as the boat is on port tack and the heel is to Leeward; therefore, it is Weather Helm also! Well, I hope I explained it clearly, but need to add that scientifically, you explained this fairly clearly, but CE and its relations to the CLR while sailing is not about the boat's heel instead, it is about the position of CE versus CLR in Forward or Aft position, which will establish whether it is beneficial or not beneficial for sailing!

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  @howarthsailing2 жыл бұрын

  Hi Chris, I think you are mistaken, both ot the boats are on the same tack in the renderings (notice the direction that the sail is filled by the wind. The boat that is heeled yo windward is not being tipped by the wind, but rather by the crew weight, which might be placed on the windward side, either on purpose or by accident. CE and CLR can move fore and aft, and side to side, and both dimensions will have effects on the helm of the boat.

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  @chriskaminski46422 жыл бұрын

  @@howarthsailing Then it is not clearly stated so, and that creates confusion. Also, heel of the boat if the sails are set properly has no effect on the helm as it becomes automatically a part of the steering due to necessary and beneficial heel associated with theory of sailing in general (5-12 degrees on monohull). There is more to it but I don’t want to create debate (example; luck of CG in the presentation). Anyway, I like the animations in your presentation! 😏

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  @howarthsailing2 жыл бұрын

  @@chriskaminski4642 this was all discussed in a series of comments that got purged in 2020 by youtube. I think that the whole CE/CLR topic is re-treated in a more recent video with clearer diagrams. Thanks for watching.

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  @stuartbluefield7692 жыл бұрын

  Might I please ask a very ignorant, amateurish question? For the sake of some medieval research I'm doing ... for example, I'm sailing from a port on a tidal river to the open sea, and assuming a boat where hitting bottom is not a concern .... would I want to leave for the sea with a low tide, since it's going OUT and would not fight me? And conversely, when I want to come back into the river from the sea, enter at high tide, which presumably helps push me in? Apologize for this terribly uneducated question.

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  @howarthsailing2 жыл бұрын

  3 considerations come to mind. First is water depth, but you said that's not an issue. The second is speed, the boat will move faster if it is going with the tide (i.e. coming into a bay while the tide is flooding, between low tide and high tide, coming in, or leaving a bay when the tide id ebbing, between high tide and low tide, going out. The third is manoeuvrability. If you have to dock on a pier, depending on the direction and speed of the tidal flow it could help you, or it could make the task harder/more risky.

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  @stuartbluefield7692 жыл бұрын

  @@howarthsailing That is precisely the kind of information I was looking for. Greatly greatly appreciate the reply. Take care.

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  @hi-lu3cd2 жыл бұрын

  Why does the stagnation line curves like this? What force is dragging the air towards the sail?

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  @howarthsailing2 жыл бұрын

  Streamlines are PUSHED by higher pressure towards lower pressure. In this case, the relatively higher pressure on the windward side of the sail pushes the stagnation streamline to leeward before it contacts the front of the sail or mast.

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  @stephengratton22942 жыл бұрын

  Fantastic explanation of vectors and I have found all your videos very clear and concise. Just one issue here. Nautical miles should be read off the parallels of latitude scale (vertical scale) and never meridians of longitude (horizontal scale) when using a chart. Meridians of longitude converge towards the poles as you travel from the equator.

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  @howarthsailing2 жыл бұрын

  You're right, that is an error at 12:45, although there is no scale available on the screen where I could have taken kts from, thank you for pointing this out. This is definitely not a chartwork tutorial, just an illustration of a practical use for vectors in sailing.

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  @yamabiru45532 жыл бұрын

  Wow

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  @outputcoupler78192 жыл бұрын

  This is super helpful, thanks! I'm getting ready to learn to sail, and my math brain insists I understand the physics, too. It is surprisingly tricky to find a video diving into the physics and "why" of sails, there's just so much practical content out there that it swamps the algorithm and theoretical content like this gets hidden.

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  @sofiaschwabacher1319 Жыл бұрын

  you're lucky you have a math brain... my brain freezes when i hear the word "angle" lol but i've been practicing sailing and need to learn theory too

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  @igbc1762 жыл бұрын

  The current does not affect the performance of the foil. I don't think what this video says it is right

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  @howarthsailing2 жыл бұрын

  What's the timestamp for the part of the video you think is incorrect?

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  @igbc1762 жыл бұрын

  Minute 16:00 The current moves respect the land and it doesn't matter if it was 1000km/h it would not affect how the boat eprforms

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  @nidaiilkay2 жыл бұрын

  excellent description with very accurate illustrations of sail boat physics..would be extremely useful if these information are compiled in a booklet

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  @jillgouhin64532 жыл бұрын

  how did you do it can you share with me , thank you

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  @steeniversen67682 жыл бұрын

  Really good go at a thorough explanation of it. Even if I think you may have time to think some things through.

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  @sanjayrajsoni2 жыл бұрын

  I pronounce you Sir as "Best Physics/Math Teacher" on KZread!!

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  @daio69682 жыл бұрын

  how did you do it can you share with me , thank you

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  @franzintegos19882 жыл бұрын

  Hi Julian, I do read and see a lot of sailing tutorials and books....your vids are one of the best sources of information.Very well made ! Easy to understand and of great value for beginners and professional sailers. Thank you for your time and effort and for sharing it, you did a great job ! Franz Vienna

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  @abdulkkhan50952 жыл бұрын

  Great video on sail trim

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  @violetfantasy25372 жыл бұрын

  My physics teacher is making me watch this, I hate her stupid class but this video does a fantastic job of explaining this topic and making it easy to understand, much better than my teacher. Good job.