Not the wind but the sail determines the direction. Using a sail on a ship
WIND DRIVING FORCE
Very interesting materials have been published on the NASA website about various factors influencing the formation of lift by an aircraft wing. There are also interactive graphical models that demonstrate that lift can also be generated by a symmetrical wing due to flow deflection.
The sail, being at an angle to the air flow, deflects it (Fig. 1d). Going through the "upper", lee side of the sail, the air flow travels a longer path and, in accordance with the principle of the continuity of the flow, moves faster than from the windward, "lower" side. The result is less pressure on the lee side of the sail than on the windward side.
When gybeing, with the sail set perpendicular to the direction of the wind, the pressure increase on the windward side is greater than the pressure decrease on the lee side, in other words, the wind pushes the yacht more than it pulls. As the boat turns sharper into the wind, this ratio will change. Thus, if the wind is blowing perpendicular to the boat's course, an increase in sail pressure to windward has less effect on speed than a decrease in pressure to leeward. In other words, the sail pulls the yacht more than it pushes.
The movement of the yacht occurs due to the fact that the wind interacts with the sail. The analysis of this interaction leads to unexpected, for many beginners, results. It turns out that the maximum speed is achieved, not at all when the wind blows exactly behind, but the wish for a “fair wind” carries a completely unexpected meaning.
Both the sail and the keel, when interacting with the flow, respectively, of air or water, create a lifting force, therefore, to optimize their work, the theory of the wing can be applied.
WIND DRIVING FORCE
The air flow has kinetic energy and, interacting with the sails, is able to move the yacht. The work of both the sail and the wing of an aircraft is described by Bernoulli's law, according to which an increase in the flow velocity leads to a decrease in pressure. When moving in the air, the wing separates the flow. Part of it bypasses the wing from above, part from below. An aircraft wing is designed so that the airflow over the top of the wing moves faster than the airflow under the underside of the wing. The result is that the pressure above the wing is much lower than below. The pressure difference is the lift force of the wing (Fig. 1a). Due to the complex shape, the wing is able to generate lift even when it cuts through the flow, which moves parallel to the plane of the wing.
The sail can only move the yacht if it is at a certain angle to the flow and deflects it. The question remains as to which part of the lifting force is associated with the Bernoulli effect, and which is the result of flow deflection. According to the classical theory of the wing, the lift force arises solely as a result of the difference in flow speeds above and below the asymmetric wing. At the same time, it is well known that a symmetrical wing is also capable of creating lift if it is installed at a certain angle to the flow (Fig. 1b). In both cases, the angle between the line connecting the anterior and posterior points of the wing and the direction of the airflow is called the angle of attack.
The lift force increases with the angle of attack, however, this dependence works only for small values of this angle. As soon as the angle of attack exceeds a certain critical level and the flow stall occurs, numerous vortices form on the upper surface of the wing, and the lift force sharply decreases (Fig. 1c).
Boaters know that gybe is not the fastest course. If the wind of the same strength is blowing at a 90 degree angle to the course, the boat is moving much faster. On a jibe, the force with which the wind pushes against the sail depends on the speed of the yacht. With maximum force, the wind presses on the sail of a yacht standing still (Fig. 2a). As the speed increases, the pressure on the sail drops and becomes minimal when the yacht reaches its maximum speed (Fig. 2b). The maximum speed on a jibe is always less than the wind speed. There are several reasons for this: firstly, friction, in any movement, some of the energy is spent on overcoming various forces that impede movement. But the main thing is that the force with which the wind presses on the sail is proportional to the square of the apparent wind speed, and the apparent wind speed on the gybe is equal to the difference between the speed of the true wind and the speed of the yacht.
Gulfwind course (at 90º to the wind) sailing yachts capable of moving faster than the wind. Within the framework of this article, we will not discuss the features of the pennant wind, we will only note that on the Gulfwind course, the force with which the wind presses on the sails depends to a lesser extent on the speed of the yacht (Fig. 2c).
The main factor that prevents the increase in speed is friction. Therefore, sailboats with little drag can reach speeds much faster than the wind, but not on a gybe. For example, a buer, due to the fact that skates have negligible slip resistance, can accelerate to a speed of 150 km / h with a wind speed of 50 km / h or even less.
The Physics of Sailing Explained: An Introduction
ISBN 1574091700, 9781574091700
4.4. The action of the wind on the sail
The boat under sail is affected by two environments: the air flow acting on the sail and the surface of the boat, and the water acting on the underwater part of the boat.Thanks to the shape of the sail, even with the most unfavorable wind (badewind), the boat can move forward. The sail resembles a wing, the largest deflection of which is 1/3-1/4 of the sail width away from the luff and has a value of 8-10% of the sail width (Fig. 44).
If the wind, which has direction B (Fig. 45, a), meets a sail on the way, it goes around it from two sides. On the windward side of the sail, the pressure is higher (+) than on the lee side (-). The resultant of the pressure forces forms a force P directed perpendicular to the plane of the sail or the chord passing through the front and rear luffs and applied to the center of the windage of the CPU (Fig. 45, b).
Rice. 44. Sail profile:
B - the width of the sail along the chord
Rice. 45. Forces acting on the sail and the hull of the boat:
a - the effect of the wind on the sail; b - the effect of wind on the sail and water on the hull of the boat
Rice. 46. The correct position of the sail in different wind directions: a - close-hauled; b - gulfwind; in - jibe
The force P is decomposed into a thrust force T, directed parallel to the center plane (DP) of the boat, forcing the boat to move forward, and a drift force D, directed perpendicular to the DP, causing drift and roll of the boat.
The force P depends on the speed and direction of the wind relative to the sail. The more
If a
The effect of water on the boat largely depends on the contours of its underwater part.
Despite the fact that with the wind, the drift force D exceeds the thrust force T, the boat moves forward. Here the lateral resistance R 1 of the underwater part of the hull affects, which is many times greater than the frontal resistance R.
Rice. 47. Pennant wind:
V I - true wind; В Ш - wind from the movement of the boat; B B - pennant wind
Force D, despite the opposition of the hull, nevertheless blows the boat off the course line. Compiled by DP and the direction of the true movement of the IP boat
Thus, the greatest thrust and the least drift of the boat can be obtained by choosing the most favorable position of the center plane of the boat and the plane of the sail relative to the wind. It is established that the angle between the DP of the boat and the plane of the sail should be equal to half
When choosing the position of the sail relative to the DP and the wind, the foreman of the boat is guided not by the true, but by the pennant (apparent) wind, the direction of which is determined by the resultant of the speed of the boat and the speed of the true wind (Fig. 47).
The jib, located in front of the forefoot, plays the role of a slat. The air flow passing between the jib and the foresail reduces the pressure on the lee side of the foresail and therefore increases its propulsive force. This happens only under the condition that the angle between the jib and the DP of the boat is slightly larger than the angle between the fore and DP (Fig. 48, a).
I think that many of us would take the chance to dive into the abyss of the sea on some kind of underwater vehicle, but still, most would prefer a sea voyage on a sailboat. When there were no planes or trains, there were only sailboats. Without them, the world was not the same.
Sailboats with straight sails brought Europeans to America. Their stable decks and capacious holds brought men and supplies for the construction of the New World. But these ancient ships also had their limitations. They were moving slowly and in almost the same direction downwind. A lot has changed since then. Today, completely different principles of controlling the force of wind and waves are used. So if you want to ride a modern one, you will have to learn physics.
Modern sailing is not just moving with the wind, it is something that affects the sail and makes it fly like a wing. And this invisible "something" is called lifting force, which scientists call lateral force.
An attentive observer could not fail to notice that no matter which way the wind blows, a sailing yacht always moves where the captain needs - even when the wind is headwind. What is the secret of such an amazing combination of stubbornness and obedience.
Many do not even realize that a sail is a wing, and the principle of operation of a wing and a sail is the same. It is based on lift only if the wing lift aircraft, using a headwind, pushes the plane up, then a vertically located sail directs the sailboat forward. To explain this from a scientific point of view, it is necessary to go back to the basics - how a sail works.
Look at the simulated process, which shows how air acts on the plane of the sail. Here you can see that the air currents under the model, which have a greater curvature, bend to go around it. In this case, the flow has to speed up a little. As a result, an area of low pressure arises - this generates lift. Low pressure on the underside pulls the sail down.
In other words, the high pressure area is trying to move towards the low pressure area by putting pressure on the sail. There is a difference in pressure, which generates lift. Due to the shape of the sail, on the inner windward side, the wind speed is less than on the leeward side. On the outside, a vacuum is formed. Air is literally sucked into the sail, which pushes the sailing yacht forward.
In fact, this principle is quite simple to understand, just look at any sailing vessel. The trick here is that the sail, no matter how it is located, transmits wind energy to the vessel, and even if visually it seems that the sail should slow down the yacht, the center of application of forces is closer to the bow of the sailboat, and the wind force provides translational motion.
But this is theory, but in practice everything is a little different. In fact, a sailing yacht cannot go against the wind - it moves at a certain angle to it, the so-called tacks.
The sailboat moves due to the balance of forces. The sails act like wings. Most of the lift they produce is directed to the side, and only a small amount is directed forward. However, the secret is in this wonderful phenomenon in the so-called "invisible" sail, which is located under the bottom of the yacht. This is a keel or in the sea language - a centerboard. The lift of the centerboard also produces lift, which is also directed mainly to the side. The keel resists roll and the opposite force acting on the sail.
In addition to the lifting force, there is also a roll - a phenomenon that is harmful to moving forward and dangerous to the crew of the ship. But for that, there is a team on the yacht to serve as a living counterbalance to the inexorable physical laws.
In a modern sailboat, both the keel and the sail work together to guide the sailboat forward. But as any novice sailor will confirm, in practice everything is much more complicated than in theory. An experienced sailor knows that the slightest change in the camber of the sail makes it possible to obtain more lift and control its direction. By varying the bow of the sail, a skilled sailor controls the size and location of the area that produces lift. A deep forward bend can create a large pressure zone, but if the bend is too great or the leading edge is too steep, the air molecules will no longer follow the bend. In other words, if the object has sharp corners, the particles of the flow cannot make a turn - the impulse of movement is too strong, this phenomenon is called the "separated flow". The result of this effect is that the sail will "wash", losing the wind.
And here are a few more practical advice use of wind energy. Optimal heading into the wind (racing close-hauled). Sailors call it "going against the wind." The apparent wind, which has a speed of 17 knots, is noticeably faster than the true wind, which creates a wave system. The difference in their directions is 12°. The course to the apparent wind is 33°, to the true wind - 45°.
The winds that are in the southern part Pacific Ocean blowing in a westerly direction. That is why our route was drawn up so that on the sailing yacht "Juliet" we move from east to west, that is, so that the wind blows in the back.
However, if you look at our route, you will notice that often, for example when moving from south to north from Samoa to Tokelau, we had to move perpendicular to the wind. And sometimes the direction of the wind changed completely and you had to go against the wind.
Juliet's route
What to do in this case?
Sailing ships have long been able to sail against the wind. The classic Yakov Perelman wrote about this for a long time well and simply in his Second book from the Entertaining Physics series. This piece I quote here verbatim with pictures.
"Sailing against the wind
It is hard to imagine how sailing ships can go "against the wind" - or, in the words of the sailors, go "hauled". True, a sailor will tell you that you cannot sail directly into the wind, but you can only move at an acute angle to the direction of the wind. But this angle is small - about a quarter of a right angle - and it seems, perhaps, equally incomprehensible: whether to sail directly against the wind or at an angle of 22 ° to it.
In fact, however, this is not indifferent, and we will now explain how it is possible to move towards it at a slight angle by the force of the wind. Let us first consider how the wind acts on the sail in general, that is, where it pushes the sail when it blows on it. You probably think that the wind always pushes the sail in the direction it is blowing. But this is not so: wherever the wind blows, it pushes the sail perpendicular to the plane of the sail. Indeed: let the wind blow in the direction indicated by the arrows in the figure below; the line AB represents the sail.
The wind pushes the sail always at right angles to its plane.
Since the wind pushes evenly over the entire surface of the sail, we replace the wind pressure with the force R applied to the middle of the sail. We decompose this force into two: the force Q, perpendicular to the sail, and the force P, directed along it (see the figure above, on the right). The last force pushes the sail nowhere, since the friction of the wind on the canvas is negligible. There remains a force Q that pushes the sail at right angles to it.
Knowing this, we can easily understand how a sailing ship can go at an acute angle into the wind. Let the KK line represent the keel line of the ship.
How can you sail against the wind.
The wind blows at an acute angle to this line in the direction indicated by the row of arrows. The line AB represents the sail; it is placed so that its plane bisects the angle between the direction of the keel and the direction of the wind. Follow the diagram for the distribution of forces. We represent the pressure of the wind on the sail by the force Q, which, we know, should be perpendicular to the sail. We decompose this force into two: the force R, perpendicular to the keel, and the force S, directed forward along the keel line of the ship. Since the movement of the vessel in the direction R meets strong water resistance (keel in sailing ships becomes very deep), then the force R is almost completely balanced by the resistance of the water. There remains only the force S, which, as you see, is directed forward and, therefore, moves the ship at an angle, as if towards the wind. [It can be shown that the force S is greatest when the plane of the sail bisects the angle between the directions of the keel and the wind.]. Usually this movement is performed in zigzags, as shown in the figure below. In the language of sailors, such a movement of the vessel is called "tacking" in the narrow sense of the word.
Let's now consider all possible wind directions relative to the boat's course.
A diagram of the ship's courses relative to the wind, that is, the angle between the direction of the wind and the vector from stern to bow (course). 
When the wind blows in the face (head wind), the sails dangle from side to side and it is impossible to move with the sail. Of course, you can always lower the sails and turn on the engine, but this is no longer relevant to sailing.
When the wind blows exactly at the back (jibe, tailwind), the dispersed air molecules put pressure on the sail from one side and the boat moves. In this case, the ship can only move slower than the wind speed. The analogy of riding a bicycle in the wind works here - the wind blows in the back and it is easier to pedal.
When moving against the wind (hauled), the sail moves not due to the pressure of air molecules on the sail from behind, as in the case of a jibe, but due to the lifting force that is created due to different air speeds on both sides along the sail. At the same time, because of the keel, the boat does not move in a direction perpendicular to the course of the boat, but only forward. That is, the sail in this case is not an umbrella, as in the case of a badewind, but an airplane wing.
During our passages, we mostly sailed with backstays and gulfwinds at an average speed of 7-8 knots with a wind speed of 15 knots. Sometimes we went against the wind, half-wind and close-hauled. And when the wind died down, they turned on the engine.
In general, a boat with a sail going against the wind is not a miracle, but a reality.
The most interesting thing is that boats can go not only against the wind, but even faster than the wind. This happens when the boat goes backstay, creating its own wind.
Interdistrict Scientific and Practical Conference "Step into the Future"Section: physics
Topic: "Physics of motion of a sailing yacht"
Head: Bukholtseva O.V., teacher of physics
MOU secondary school №11, Severobaikalsk
Severobaikalsk
We want to pay attention to the relevance of teaching beginners: 2
Novelty 3
Yachts of Severobaikalsk 3
Physics 4
Driving force of the wind 4
Bernoulli's Law 4
Heading jibe 5
Gulfwind 6 course
Weight location and water-case interaction 7
Longitudinal weight distribution. Sharp Courses 8
Longitudinal weight distribution. Complete courses 8
Lateral weight distribution at fair wind 9
Lateral weight distribution with tailwind and wave 9
Conclusion 11
We have been sailing for 10 years. At first we went on Optimists, over time we gained experience and began to sail on Luch-mini and Cadet class yachts. Now, having become older and even more experienced, we can manage a yacht of the Luch-standard class and cruising ships. Participated in regional regattas in Severobaikalsk, Bratsk and Ust-Ilimsk. Repeatedly occupied prize-winning places and were winners.
We want to pay attention to the relevance of teaching beginners:
In the summer, at the Baikal Regatta camp, we, the “old men”, teach sailing to beginners. Training time - 21 days. And here the future yachtsman understands how important knowledge of physics is, and not intuition. After all, every "newbie" believes that the main thing in the movement of the wind and preferably fair. Here is the first and biggest mistake. And there are many. Therefore, the purpose of our work is to create a manual for studying the physics of the movement of a sailing yacht.To reach the goal, we need to solve the followingtasks :
Consider the types of yachts that are available in Severobaikalsk.
To study the nature of the movement of the yacht.
To challenge the point of view of newcomers that a tailwind is the most important thing.
To study how the location of the weight affects the speed of the yacht.
Consider the influence of the physical characteristics of water on the speed of the yacht.
Collection and analysis of information.
Interview and survey.
Performing calculations.
Compilation of tables.
Yacht testing.
Novelty
There is a description of the physics of yacht movement in books and websites, but in all these materials, each factor that affects the movement of the yacht, namely the interaction of wind with the sail, the distribution of weight on the yacht, the interaction of water with the hull, is considered separately, which, in our opinion , not properly. After all, to win, a yachtsman needs to combine these three factors into a single whole.Yachts of Severobaikalsk
Some classes of yachts are available in Severobaikalsk, such as:|
Name |
Displacement |
Length |
windage |
Crew |
|
Ray |
≈ 160 kg |
4.23 m |
7.05 m2 |
1 person |
|
Optimist |
emergency buoyancy of at least 90 liters |
≈ 2.3 m |
3.33 m2 |
1 person |
|
Finn |
107kg |
4.50m |
10 m2 |
1 person |
|
Cadet |
95kg |
3.22 m |
9.41 m2 |
2 people |
|
Assol |
630kg |
5.53m |
13.66 m2 |
4 people |
http://minitonnik.com.ua/?q=node/126
Physics
The driving force of the wind
The movement of the yacht is due to the fact that the wind interacts with the sail. The analysis of this interaction leads to unexpected, for many beginners, results. It turns out that the maximum speed is achieved, not at all when the wind blows exactly behind, but the wish for a “fair wind” carries a completely unexpected meaning.Both the sail and the keel, when interacting with the flow, respectively, of air or water, create a lifting force, therefore, to optimize their work, the theory of the wing can be applied.
Bernoulli's law
The air flow has kinetic energy and, interacting with the sails, is able to move the yacht. The work of both the sail and the wing of an aircraft is described by Bernoulli's law, according to which an increase in the flow velocity leads to a decrease in pressure. When moving in the air, the wing separates the flow. Part of it bypasses the wing from above, part from below. An aircraft wing is designed so that the airflow over the top of the wing moves faster than the airflow under the underside of the wing. As a result, the pressure above the wing is much lower than below. The difference in pressure is the lift force of the wing.
The sail can only move the yacht if it is at a certain angle to the flow and deflects it. The question remains: how much of the lift is due to the Bernoulli effect, and how much is the result of flow deflection. According to the classical theory of the wing, the lift force arises solely as a result of the difference in flow speeds above and below the asymmetric wing. It is well known that a symmetrical wing is also capable of generating lift if it is set at a certain angle to the flow. In both cases, the angle between the line connecting the anterior and posterior points of the wing and the direction of the airflow is called the angle of attack.
The lift force increases with the angle of attack, however, this dependence works only for small values of this angle. As soon as the angle of attack exceeds a certain critical level and the flow stalls, numerous vortices form on the upper surface of the wing, and the lift force decreases sharply.
The sail, being at an angle to the air flow, deflects it. Going through the "upper", lee side of the sail, the air flow travels a longer path and, in accordance with the principle of the continuity of the flow, moves faster than from the windward, "lower" side. As a result, the pressure on the lee side of the sail is much lower than on its windward side.
gybe course
When moving on course jibe, when the sail is set perpendicular to the direction of the wind, the degree of pressure increase on the windward side is greater than the degree of pressure decrease on the lee side, in other words, the wind pushes the yacht more, than pull. As the boat turns sharper into the wind, this ratio will change. Thus, if the wind is blowing perpendicular to the boat's course, an increase in sail pressure to windward has less effect on speed than a decrease in pressure to leeward. As a result, with this course, the sail pulls the yacht more than it pushes.Boaters know that gybe is not the fastest course. If the wind of the same strength is blowing at a 90 degree angle to the course, the boat is moving much faster. On a jibe, the force with which the wind pushes against the sail depends on the speed of the yacht. As the speed increases, the pressure on the sail drops and becomes minimal when the yacht reaches its maximum speed. The maximum speed on a jibe is always less than the wind speed.. There are several reasons for this: firstly, friction, in any movement, some of the energy is spent on overcoming various forces that impede movement. But the main thing is that the force with which the wind presses on the sail is proportional to the square of the apparent wind speed, and the apparent wind speed on the gybe is equal to the difference between the speed of the true wind and the speed of the yacht.
Gulfwind course
On a gulfwind course (at 90º to the wind), sailing yachts are able to move faster than the wind. We only note that on a Gulfwind course, the force with which the wind presses on the sails depends to a lesser extent on the speed of the yacht..
Location of weight and water-hull interaction
It is useful for everyone to pay attention to the effect that the distribution of weight has in a given situation. Every time we offer to talk about yacht tuning, beginners are sure that we will talk about spars and sails. But there is an area that is rarely remembered - this is the position of the hull in the water - how to "balance", "trim the ship", "correctly distribute the ballast on the ship".Obviously, the correct distribution of weight can play a decisive role in determining the position of the boat at the finish line. This problem can be solved by transferring weight to one or another point on the yacht.
The main principle of yacht balancing is to find the balance of forces acting on the hull and to maintain the position of the hull in a state that will provide maximum speed under certain weather conditions.
Longitudinal weight distribution. sharp courses
Light breeze
A common problem in light winds is a decrease in the yacht's tendency to luff. Because of this, it becomes difficult to track changes in lift and go as sharply as possible into the wind. In light winds, the position of the sails and rigging reduces the tendency to luff and leaves sailors without the feel they are used to. The classic solution to this problem is to list the boat to leeward to change the shape of the bottom and increase the tendency to luff. Unfortunately, for most hulls, this step increases the wetted surface area of the hull, as well as increasing stern drag and, consequently, reducing the speed of the yacht. If instead we shift the weight forward and weight the nose, the center of lateral drag shifts forward, the tendency to roll increases, and the wetted surface area remains the same. Obviously, by using the roll to turn to windward, the helmsman simply increases the drag on the hull.
Fresh breeze
Longitudinal weight distribution. Complete courses
Light breeze
The length of the waterline is one of the most important parameters that determines the speed of displacement hulls. As a result of the deepening of the bow, the stern can rise, and this will drastically reduce the length of the waterline. (In light winds, the length of the waterline is less important than the area of the wetted surface). If you're sitting comfortably, chances are you're not moving forward enough. Look at the water astern: if you see swirling currents, move forward.
Medium wind
If you take into account the effect that waves create, moving back and forth can greatly help to maintain planing mode.
Strong wind
Lateral weight distribution with tailwind
weak wind
If the wind strength is sufficient, the following trick can be performed on the gybe.
Move as far forward as possible and lean the boat a few degrees into the wind while ruddering to keep the boat on course. At first you will feel a little rudder pull, but once the centerboard begins to generate lift, the pressure will decrease, the rudder will become light, neutral, and set in the desired direction. Such a turn is also very effective because it allows you to gain additional height in the wind. But be careful: if during such a maneuver a wave appears that extinguishes the speed, the effect can be disastrous.
Medium wind
On modern yachts, there are many tricks that can be used to reduce the tendency to cast. But if you make the yacht heel to windward, the problem disappears.
Lateral weight distribution with tailwind and wave
BackstayWhen sailing full courses in heavy seas, the shape of the hull should be used to facilitate steering of the yacht. In order to ride the following wave and prevent excessive roll, it is necessary to move the steering wheel sharply, and this reduces the chances of success.
waddling
If we consider the forces acting on the boat, it becomes clear why the nose of the boat goes into the water when weaving. Roll creates lift on the rudder, causing the nose to sink and making it harder to bear. To compensate for this, it is necessary to open the boom sheet, and the bow will begin to move downwind. Fine course corrections can be made with the rudder. During the turn, it is better to shift the weight of the team back; this will raise the nose, and this will help the wind to turn it in the right direction.
tack
I know from experience with small sailing dinghies that speed can drop drastically during a turn. One of the reasons for this is the movement of the helmsman in the cockpit. Diving under the boom during the turn, the helmsman shifts back, melts the stern, and it starts to work as a good brake. You can correct the situation if you bypass the shoulder strap facing backwards. At the same time, the center of gravity shifts not so far back, because the “fifth point of support” is heavier than the head! This is an effective maneuver, but be careful not to bend too much when dodging the boom - one movement of your foot and the effect of your actions is gone. (During the preparation of the text, this recommendation aroused serious doubts. After all, when transplanting backwards, the helmsman loses orientation, control over what is happening around. We invite readers to make their own decision about which method is better. - Approx. Translators.)
So, how do we distribute the weight:
|
Light breeze |
Medium wind |
Fresh breeze |
|
move forward as long as you feel comfortable; · do not heel the yacht to the leeward side, it is better to move forward. |
Remember that the steering wheel is the brake. Try to keep it in the middle position, change course by working with sails; · as soon as the yacht begins to plan, move back; as soon as the yacht switches to displacement mode, move forward; · When you bear away, move back, start the maneuver by easing the sheets. |
· on full headings, keep the bow of the yacht as high as possible above the water; · on sharp courses, if you move too far back - the yacht will slow down astern, too far forward - the yacht will scour the wave. |
The main factor that prevents the increase in speed is friction. Therefore, sailboats with little drag can reach speeds much faster than the wind, but not on a gybe. For example, a buer, due to the fact that skates have negligible slip resistance, can accelerate to a speed of 150 km / h with a wind speed of 50 km / h or even less.
Conclusion
Conclusion: The city of Severobaikalsk is located on the shores of Lake Baikal, in the water area there is the only yacht club in Buryatia, which is a local attraction for tourists and schoolchildren. During the short northern summer, many of them dream of learning to sail on yachts. If the study of the equipment of the yacht can be dealt with on the shore, then the theoretical course of the physics of the movement of the yacht is difficult to master. And this manual will help everyone to properly distribute the weight, adjust the sail and choose a course according to their physical data and skills.
