The direction of the wind relative to the ship. How does a sail work? Now let's look at how the sails work on a yacht

Yacht's course relative to the wind (Rumb of sailing)

Steep close-hauled (tacking). When a boat sails on a course as close (as possible) to the direction against the wind without lapping the luff, it is said to be sailing close-hauled. Sails should be chosen as strong as possible.

Full close-hauled. With this course, the yacht tacks less. The wind does not blow straight towards or towards the stern, but into the side of the boat, so the sails should be slightly trimmed compared to a steep close-hauled wind. as much as possible until they begin to rinse.

Gulfwind. A yacht moving under sail at right angles to the wind is said to be tacking. Since the wind is blowing on board, the sails are trimmed about halfway.

Backstay. When the wind is blowing from behind, but not directly astern, the yacht heads backstay. The sails are etched until the luff begins to rinse, and then they are selected to a sufficient extent for it to disappear. In this position the wind is coming from the stern and the spinnaker can be raised.

Fordewind. With a fair wind, the sails are completely trimmed. They are spread out to catch as much wind as possible, the yacht goes with the wind. When the wind blows directly astern, the jib can flutter because it is blocked by the mainsail. In this case, you can either put it on the other side, where it will fill with wind again, or lower it and install a spinnaker instead. (Large parachute-shaped spinnakers can only be used in a tailwind.)

Trimming the sail

The clew must keep an eye on the sails at all times - they must be set so that the yacht can show its best qualities. This means constantly watching and adjusting the leading edge of each sail. Every time a yacht changes course, the sails must be re-set and adjusted to operate at their full potential. Likewise, their position must be changed in accordance with each change in wind direction. If a sail luffs, the boat loses speed, so, especially in racing, a clew sailor must always be ready to trim the sails at the first sign of a luff luff.

In order for the yacht to tack when the wind is blowing to the windward side (moving against the wind), the sheets should be fully adjusted to reduce sloping, then the ship moves forward at maximum speed.

The position of the sail should be changed smoothly, in accordance with any change in course. When the ship moves away from the wind, the sails are trimmed during the turn so that on the new course they can be set as quickly as possible without rinsing. When the yacht is brought to windward, the sheets are pulled out during the turn to prevent any signs of lapping.

This way the yacht can maneuver at full speed all the time and both sails will work at their maximum.

Setting sails on a dinghy

Small dinghies can improve their seaworthiness on various sailing courses by using a centerboard.

When sailing into the wind, maximum lateral resistance is required, so the centerboard must be lowered completely. However, when the wind is blowing from behind (towards the stern), no lateral resistance is required, so the centerboard can be fully raised. In all intermediate positions, the centerboard should be installed in accordance with the course of movement.

Before looking at how a sail works, there are two short but important points to consider:
1. Determine what kind of wind affects the sails.
2.Talk about specific marine terminology associated with courses relative to the wind.

True and apparent winds in yachting.

The wind that acts on a moving ship and everything on it is different from the one that acts on any stationary object.
Actually, the wind as an atmospheric phenomenon blowing relative to land or water is what we call true wind.
In yachting, the wind relative to a moving yacht is called apparent wind and is the sum of the true wind and the oncoming air flow caused by the movement of the vessel.
The apparent wind always blows at a sharper angle to the boat than the true wind.
The apparent wind speed can be greater (if the true wind is headwind or sidewind), or less than the true wind (if it is from a tailwind).

Directions relative to the wind.

In the wind means from the direction from which the wind blows.
Downwind- from the direction the wind blows.
These terms, as well as derivatives from them, such as “windward”, “leeward”, are used very widely, and not only in yachting.
When these terms are applied to a ship, it is customary to also talk about the windward and leeward sides.
If the wind blows from the starboard side of the yacht, then this side is called windward, left side - leeward respectively.
Port and starboard tack are two terms directly related to the previous ones: if the wind blows to the starboard side of the ship, then they say that it is sailing on the starboard tack, if it is on the left, then on the left.
In English nautical terminology, what is associated with starboard and port is different from the usual Right and Left. They say Starboard about the starboard side and everything related to it, and Port about the left side.

Courses relative to the wind.

Courses relative to the wind vary depending on the angle between the direction of the apparent wind and the direction the vessel is moving. They can be divided into acute and full.

Close-hauled is a sharp course relative to the wind. when the wind blows at an angle of less than 80°. There can be a steep close-hauled wind (up to 50°) or a full close-hauled wind (from 50 to 80°).
Full courses relative to the wind are courses when the wind blows at an angle of 90° or more to the direction the yacht is moving.
These courses include:
Gulfwind - the wind blows at an angle of 80 to 100°.
Backstay - the wind blows at an angle from 100 to 150° (steep backstay) and from 150 to 170° (full backstay).
Fordewind - the wind blows astern at an angle of more than 170°.
Leftist - the wind is strictly headwind or close to it. Since a sailing ship cannot move against such a wind, it is more often called not a course, but a position relative to the wind.

Maneuvers relative to the wind.

When a yacht under sail changes its course so that the angle between the wind and the direction of motion decreases, then the ship is said to be is given. In other words, to flatten means to go at a sharper angle to the wind.
If the reverse process occurs, i.e. the yacht changes course towards increasing the angle between it and the wind, the ship falls away .
Let us clarify that the terms (“lead” and “fall”) are used when the boat changes course relative to the wind within the same tack.
If the ship changes tack, then (and only then!) such a maneuver in yachting is called a turn.
There are two different ways to change tack and, accordingly, two turns: tack And jibe .
A tack is a turn into the wind. The vessel is driven, the bow of the boat crosses the wind line, at some point the vessel passes through the left-hand position, after which it lies on the other tack.
Yachting when jibes occurs in the opposite way: the ship falls away, the stern crosses the wind line, the sails are transferred to the other side, the yacht lies on a different tack. Most often this is a turn from one full course to another.

Sail operation during yachting.

One of the main challenges for a sailor when working with sails is to orient the sail at the optimal angle relative to the wind to best propel the sail forward. To do this, you need to understand how the sail interacts with the wind.
The work of a sail is in many ways similar to the work of an airplane wing and occurs according to the laws of aerodynamics. For particularly curious yachtsmen, you can learn more about the aerodynamics of a sail as a wing in a series of articles:. But it’s better to do this after reading this article, gradually moving from easy to more complex material. Although, who am I telling this to? Real yachtsmen are not afraid of difficulties. And you can do everything exactly the opposite.

The main difference between a sail and an aircraft wing is that for an aerodynamic force to appear on the sail, a certain non-zero angle is needed between it and the wind; this angle is called the angle of attack. The airplane wing has an asymmetrical profile and can operate normally at zero angle of attack, but the sail does not.
As the wind flows around the sail, an aerodynamic force arises, which ultimately moves the yacht forward.
Let's consider the operation of a sail in yachting at different courses relative to the wind. First, for simplicity, let's imagine that a mast with one sail is dug into the ground and we can direct the wind at different angles to the sail.

Angle of attack 0°. The wind blows along the sail, the sail flutters like a flag. There is no aerodynamic force on the sail, there is only drag force.
Angle of attack 7°. An aerodynamic force begins to appear. It is directed perpendicular to the sail and is still small in size.
The angle of attack is about 20°. The aerodynamic force has reached its maximum value and is directed perpendicular to the sail.
Angle of attack 90°. Compared to the previous case, the aerodynamic force did not change significantly either in magnitude or direction.
Thus, we see that the aerodynamic force is always directed perpendicular to the sail and its magnitude practically does not change in the angle range from 20 to 90°.
Angles of attack greater than 90° do not make sense to consider, since the sails on a yacht are usually not set at such angles relative to the wind.

The above dependences of the aerodynamic force on the angle of attack are largely simplified and averaged.
In fact, these properties vary markedly depending on the shape of the sail. For example, a long, narrow and fairly flat mainsail of racing yachts will have a maximum aerodynamic force at an angle of attack of about 15°; at higher angles the force will be slightly less. If the sail is more potbellied and does not have a very large aspect ratio, then the aerodynamic force on it can be maximum at an angle of attack of about 25-30°.

Now let's look at how a sail works on a yacht.

For simplicity, let's imagine that there is only one sail on the yacht. Let it be a grotto.
First, it’s worth looking at how the yacht + sail system behaves when moving on the sharpest courses relative to the wind, since this usually raises the most questions.

Let’s say the yacht is affected by wind at an angle of 30-35° to the hull. By orienting the sail on course at an angle of approximately 20° to the wind, we obtain a sufficient aerodynamic force A on it.
Since this force acts at right angles to the sail, we see that it pulls the yacht strongly to the side. By decomposing the force A into two components, you can see that the forward thrust force T is several times less than the force pushing the boat sideways (D, drift force).
What causes the yacht to move forward in this case?
The fact is that the design of the underwater part of the hull is such that the resistance of the hull to movement to the side (the so-called lateral resistance) is also several times greater than the resistance to movement forward. This is facilitated by the keel (or centreboard), rudder and the very shape of the hull.
However, lateral resistance occurs when there is something to resist, i.e., for it to start working, some sideways displacement of the body, the so-called wind drift, is required.

This displacement naturally occurs under the action of the lateral component of the aerodynamic force, and as a response, a lateral drag force S immediately arises, directed in the opposite direction. As a rule, they balance each other at a drift angle of about 10-15°.
So, it is obvious that the lateral component of the aerodynamic force, most pronounced on sharp courses relative to the wind, causes two undesirable phenomena: wind drift and roll.

Wind drift means that the yacht's trajectory does not coincide with its centreline (diameter plane, or DP, is a smart term for the bow-stern line). There is a constant shift of the yacht to the wind, moving as if a little sideways.
It is known that when yachting on a close-hauled course under average weather conditions, the wind drift as the angle between the DP and the actual trajectory is approximately 10-15°.

Advance against the wind. Tacking.

Since yachting under sails is not possible strictly against the wind, and you can only move at a certain angle, it would be good to have an idea of how sharply the yacht can move in degrees to the wind. And what, accordingly, is that slow sector of courses relative to the wind, in which movement against the wind is impossible.
Experience shows that a regular cruising yacht (not a racing yacht) can effectively sail at an angle of 50-55° to the true wind.

Thus, if the goal that needs to be achieved is located strictly against the wind, then yachting to it will not take place in a straight line, but in a zigzag, first on one tack, then on the other. In this case, on each tack, naturally, you will need to try to sail as sharply as possible into the wind. This process is called tacking.

The angle between the trajectories of yachts on two adjacent tacks when tacking is called tacking. Obviously, with a sharpness of movement to the wind of 50-55°, the tacking angle will be 100-110°.

The magnitude of the tacking angle shows us how effectively we can move towards the target if it is strictly against the wind. For an angle of 110°, for example, the path to the target increases by 1.75 times compared to moving in a straight line.

Sail operation on other courses relative to the wind

It is obvious that already on a gulfwind course the thrust force T significantly exceeds the drift force D, so the drift and roll will be small.

With the backstay, as we see, not much has changed compared to the gulfwind course. The mainsail is placed in a position almost perpendicular to the DP, and this position is extreme for most yachts; it is technically impossible to deploy it even further.

The position of the mainsail on the gybe course is no different from the position on the backstay course.
Here, for simplicity, when considering the physics of the process in yachting, we take into account only one sail - the mainsail. Typically, a yacht has two sails - a mainsail and a staysail (headsail). So, on a gybe course, the jib (if it is located on the same side as the mainsail) is in the wind shadow of the mainsail and practically does not work. This is one of several reasons why jibes are not a favorite among boaters.

Port tack Starboard tack

Ship's heading relative to the wind- the angle between the direction of the wind and the center plane (DP) of the vessel, that is, the heading angle to the point on the horizon from where the wind blows, expressed in angular degrees or points. Depending on which side the wind is blowing from, a distinction is made between starboard and port tack courses. Wind courses have their own names:

Leventik

Leventik(fr. le vent) - a position when the wind blows almost directly in front of the ship. A sailing ship cannot sail against the wind, so “leftward” is not a course; it is correct to say “leftward position.”

Fordewind

Fordewind(Dutch voor de wind), or downwind - a course in which the wind is directed towards the stern of the ship. A ship going into a gybe is said to be “going with full wind.” The angle between the wind direction and the center plane of the vessel in this case is about 180°.

Fordewind is the same “fair wind” that sailors desire, although in sailing this course is by no means the fastest, as one would expect. In addition, it requires attention and skill from the helmsman to control additional sails (usually a spinnaker). In this case, the sail is placed perpendicular to the direction of the wind, the thrust on it is created mainly due to the direct pressure of the wind on the sail. Light wind on this course is practically not felt, since the speed of the apparent wind is equal to the difference between the speed of the true wind and the speed of the oncoming air flow.

Gulfwind

Backstay

Beidewind

The best sailing ships sail at an angle of 30-35° to the direction of the apparent wind. Due to the addition of the vectors of wind speed and oncoming air flow, the speed of the apparent wind on a close-hauled course turns out to be maximum, as well as the lifting force on the sail, proportional to the square of the wind speed. The drift force also reaches its maximum value. If you try to sail at a sharper angle to the wind, the speed of the vessel will decrease, the sail will begin to flap, the lift will decrease and, finally, a moment will come when the drift and resistance of the water to movement will far exceed the thrust. The ship will lose speed.

Tacking

A sailing ship cannot sail directly against the wind. If it is necessary to get to any point located to windward, then tacking is used - moving towards the target on a close-hauled course on alternating tacks. To change tack you must make a turn. A distinction is also made between tacking in the wind, when a sailing vessel (usually a sailing catamaran or a dinghy skiff) follows a backstay course with a change of tacks, rather than a gybe course, to follow exactly with the wind. For high-speed sailing yachts, this method of reaching a leeward goal is faster.

There are two types of turns relative to the wind:

Tack. In this maneuver, the bow of the sailing vessel crosses the wind line. The vessel is brought to the left, then falls on another tack, to the desired course. This maneuver is easier to perform on ships with oblique sails - Bermuda, gaff, lateen. For ships with straight sails, such a maneuver requires a very experienced and large crew. The sails need to be thrown onto the other tack in a certain sequence and strictly on time: the sails on the mizzen mast are brought to the wind first and help to bring it up. The sails on the foremast and, less critically, the mainmast are carried when passing through the wind line, and help to fall away. Otherwise, the ship may “miss the left,” lose speed and stop listening to the rudder.

Jibe. During this maneuver, the wind line is crossed by the stern of the sailing ship. Thus, the wind is always fair and presents fewer difficulties for ships with square rigs. But for sailing yachts with an oblique rig, a change of tack is accompanied by a rapid (and, as a rule, for inexperienced crews, a sudden) transfer of sails from one tack to another. In this case, the spar and rigging experience a dynamic shock. Flying booms can either injure or throw unwary people overboard. To avoid such spontaneous turning, the sails are carried under control.

If, while maintaining the tack, you need to go at a sharper angle to the direction of the wind, then they say that you need to not turn, but “bring to the wind.” If, on the contrary, you need to increase the angle between the direction of the wind and the boat’s DP, then they say that it is necessary to “fall into the wind.” By changing the course relative to the wind, they simultaneously change the position of the sail in order to maintain the optimal angle of attack. To do this, it is necessary to pull him towards the DP - “select”, or release him - “poison”.

Depending on the side from which the wind is blowing, courses relative to the wind can be starboard or port tack.

With a heading wind angle equal to 26 points, the close-hauled starboard tack in the sailing fleet was sometimes called starboard, and the left tack (wind heading angle of 6 points) was called a backboard. To clarify the course relative to the wind, the following expressions were used: “the ship is sailing on a starboard tack of 7 points to the wind” (that is, close-hauled at a heading wind angle of 78°); “The ship is sailing backstay on a starboard tack of 10 points” (that is, the heading angle of the wind is 112°); “The ship is heading fuller than 6 points” (that is, the backstay at a heading angle of 12 points, or 135°). The concept of “close-hauled” is also used as the sharpest course relative to the wind, at which a sailing ship can move forward (it ranges from 3 to 6 points 33.3/4° to 67.1/2°); steep and full backstay (up to 12 points and more than 12 points, or up to 135 ° and more than 135 °, respectively).

Calculation of the ship's path based on known values of the compass wind direction, course relative to the wind, compass corrections and drift is called in the sailing fleet correction of rhumbs.

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Notes

// Military Encyclopedia: [in 18 volumes] / ed. V. F. Novitsky I. V. Sytin, 1911-1915.
// Military Encyclopedia: [in 18 volumes] / ed. V. F. Novitsky [and others]. - St. Petersburg. ; [M.]: Type. t-va I.V. Sytin, 1911-1915.
// Encyclopedic Dictionary of Brockhaus and Efron: in 86 volumes (82 volumes and 4 additional). - St. Petersburg. , 1890-1907.
// Military Encyclopedia: [in 18 volumes] / ed. V. F. Novitsky [and others]. - St. Petersburg. ; [M.]: Type. t-va I.V. Sytin, 1911-1915.

Literature

Marine encyclopedic reference book / N. N. Isanin. - Leningrad: Shipbuilding, 1986. - T. 1, 2. - 512, 520 p.
Naval dictionary / V. N. Chernavin. - Moscow: Voenizdat, 1990. - 511 p. - ISBN 5-203-00174-X.

An excerpt characterizing the Course relative to the wind

In the first days of October, another envoy came to Kutuzov with a letter from Napoleon and a peace proposal, deceptively indicated from Moscow, while Napoleon was already not far ahead of Kutuzov, on the old Kaluga road. Kutuzov responded to this letter in the same way as to the first one sent with Lauriston: he said that there could be no talk of peace.
Soon after this, from the partisan detachment of Dorokhov, who went to the left of Tarutin, a report was received that troops had appeared in Fominskoye, that these troops consisted of the Broussier division and that this division, separated from other troops, could easily be exterminated. The soldiers and officers again demanded action. The staff generals, excited by the memory of the ease of victory at Tarutin, insisted on Kutuzov to implement Dorokhov’s proposal. Kutuzov did not consider any offensive necessary. What happened was the mean, what had to happen; A small detachment was sent to Fominskoye, which was supposed to attack Brusier.
By a strange coincidence, this appointment - the most difficult and most important, as it turned out later - was received by Dokhturov; that same modest, little Dokhturov, whom no one described to us as drawing up battle plans, flying in front of regiments, throwing crosses at batteries, etc., who was considered and called indecisive and uninsightful, but the same Dokhturov, whom during all Russian wars with the French, from Austerlitz until the thirteenth year, we find ourselves in charge wherever the situation is difficult. In Austerlitz, he remains the last at the Augest dam, gathering regiments, saving what he can, when everything is running and dying and not a single general is in the rearguard. He, sick with a fever, goes to Smolensk with twenty thousand to defend the city against the entire Napoleonic army. In Smolensk, as soon as he dozed off at the Molokhov Gate, in a paroxysm of fever, he was awakened by cannonade across Smolensk, and Smolensk held out all day. On Borodino Day, when Bagration was killed and the troops of our left flank were killed in a ratio of 9 to 1 and the entire force of the French artillery was sent there, no one else was sent, namely the indecisive and indiscernible Dokhturov, and Kutuzov hurries to correct his mistake when he sent there another. And small, quiet Dokhturov goes there, and Borodino is the best glory of the Russian army. And many heroes are described to us in poetry and prose, but almost not a word about Dokhturov.
Again Dokhturov is sent there to Fominskoye and from there to Maly Yaroslavets, to the place where the last battle with the French took place, and to the place from which, obviously, the death of the French already begins, and again many geniuses and heroes are described to us during this period of the campaign , but not a word about Dokhturov, or very little, or doubtful. This silence about Dokhturov most obviously proves his merits.
Naturally, for a person who does not understand the movement of a machine, when he sees its action, it seems that the most important part of this machine is that chip that accidentally fell into it and, interfering with its progress, flutters in it. A person who does not know the structure of the machine cannot understand that it is not this splinter that spoils and interferes with the work, but that small transmission gear that silently turns, is one of the most essential parts of the machine.
On October 10, the same day that Dokhturov walked half the road to Fominsky and stopped in the village of Aristov, preparing to exactly carry out the given order, the entire French army, in its convulsive movement, reached Murat’s position, as it seemed, in order to give The battle suddenly, for no reason, turned left onto the new Kaluga road and began to enter Fominskoye, in which Brusier had previously stood alone. Dokhturov at that time had under his command, in addition to Dorokhov, two small detachments of Figner and Seslavin.
On the evening of October 11, Seslavin arrived in Aristovo to his superiors with a captured French guardsman. The prisoner said that the troops that had entered Fominskoe today constituted the vanguard of the entire large army, that Napoleon was right there, that the entire army had already left Moscow for the fifth day. That same evening, a servant who came from Borovsk told how he saw a huge army entering the city. Cossacks from Dorokhov's detachment reported that they saw the French Guard walking along the road to Borovsk. From all this news it became obvious that where they thought they would find one division, there was now the entire French army, marching from Moscow in an unexpected direction - along the old Kaluga road. Dokhturov did not want to do anything, since it was not clear to him now what his responsibility was. He was ordered to attack Fominskoye. But in Fominskoe there had previously only been Broussier, now there was the entire French army. Ermolov wanted to act at his own discretion, but Dokhturov insisted that he needed to have an order from His Serene Highness. It was decided to send a report to headquarters.
For this purpose, an intelligent officer was elected, Bolkhovitinov, who, in addition to the written report, had to tell the whole matter in words. At twelve o'clock at night, Bolkhovitinov, having received an envelope and a verbal order, galloped, accompanied by a Cossack, with spare horses to the main headquarters.

The night was dark, warm, autumn. It had been raining for four days now. Having changed horses twice and galloping thirty miles along a muddy, sticky road in an hour and a half, Bolkhovitinov was in Letashevka at two o'clock in the morning. Having dismounted from the hut, on the fence of which there was a sign: “General Headquarters,” and abandoning his horse, he entered the dark vestibule.
- The general on duty, quickly! Very important! - he said to someone who was rising and snoring in the darkness of the entryway.
“We’ve been very unwell since the evening; we haven’t slept for three nights,” the orderly’s voice whispered intercessively. - You must wake up the captain first.
“Very important, from General Dokhturov,” said Bolkhovitinov, entering the open door he felt. The orderly walked ahead of him and began to wake someone up:
- Your honor, your honor - the courier.
- I'm sorry, what? from whom? – said someone’s sleepy voice.
– From Dokhturov and from Alexey Petrovich. “Napoleon is in Fominskoye,” said Bolkhovitinov, not seeing in the darkness who asked him, but by the sound of his voice, suggesting that it was not Konovnitsyn.
The awakened man yawned and stretched.
“I don’t want to wake him up,” he said, feeling something. - You're sick! Maybe so, rumors.
“Here’s the report,” said Bolkhovitinov, “I’ve been ordered to hand it over to the general on duty immediately.”
- Wait, I’ll light a fire. Where the hell do you always put it? – turning to the orderly, said the stretching man. It was Shcherbinin, Konovnitsyn's adjutant. “I found it, I found it,” he added.
The orderly was chopping the fire, Shcherbinin was feeling the candlestick.
“Oh, disgusting ones,” he said with disgust.
In the light of the sparks, Bolkhovitinov saw the young face of Shcherbinin with a candle and in the front corner a still sleeping man. It was Konovnitsyn.
When the brimstones lit up with a blue and then a red flame on the tinder, Shcherbinin lit a tallow candle, from the candlestick of which the Prussians ran, gnawing it, and examined the messenger. Bolkhovitinov was covered in dirt and, wiping himself with his sleeve, smeared it on his face.
-Who is informing? - said Shcherbinin, taking the envelope.
“The news is true,” said Bolkhovitinov. - And the prisoners, and the Cossacks, and the spies - they all unanimously show the same thing.
“There’s nothing to do, we have to wake him up,” said Shcherbinin, getting up and approaching a man in a nightcap, covered with an overcoat. - Pyotr Petrovich! - he said. Konovnitsyn did not move. - To the main headquarters! – he said, smiling, knowing that these words would probably wake him up. And indeed, the head in the nightcap rose immediately. On Konovnitsyn’s handsome, firm face, with feverishly inflamed cheeks, for a moment there remained the expression of dreams of a dream far from the present situation, but then suddenly he shuddered: his face took on its usually calm and firm expression.
- Well, what is it? From whom? – he asked slowly, but immediately, blinking from the light. Listening to the officer’s report, Konovnitsyn printed it out and read it. As soon as he had read it, he lowered his feet in woolen stockings onto the earthen floor and began to put on his shoes. Then he took off his cap and, combing his temples, put on his cap.
-Are you there soon? Let's go to the brightest.
Konovnitsyn immediately realized that the news brought was of great importance and that there was no time to delay. Whether it was good or bad, he did not think or ask himself. He wasn't interested. He looked at the whole matter of war not with his mind, not with reasoning, but with something else. There was a deep, unspoken conviction in his soul that everything would be fine; but that you don’t need to believe this, and especially don’t say this, but just do your job. And he did this work, giving it all his strength.

At first, it may seem that knowing the course of your ship relative to the wind is necessary only for yachtsmen - sailboats, teachers of courses for navigators of small boats and Christopher Columbus. But that's not true.

Sometimes I had to be in situations, coming to the rescue, when a clearly given instruction, using the usual “wind” terms, baffled the would-be navigator. Explaining with fingers, in emergency cases, is, of course, unacceptable.

And, of course, effective movement on a tacking sailing yacht or dinghy without knowledge of the basics is unthinkable. In teaching yachting, this section occupies the most important place, along with sail theory. The theoretical component is no less fascinating than the practical one. But, to the point.

As we know (should know), a modern yacht sail and an airplane wing, in some cases, are one and the same. And, also, when air flow moves through it, areas of high and low pressure are created. The difference between them creates lift (of course, with a tailwind, a sail standing perpendicular to the center plane of the vessel cannot be considered an aerodynamic wing). The only difference is that a classic sail must be filled with wind in order for it to acquire the profile of a wing.

If we let go, that is, let go of the sheet, then the sail will simply stand up in the wind (let’s assume that we have a dinghy that does not have standing rigging: shrouds, spreaders and everything that can prevent the sail from simply turning around the mast). In this form, the sail is, of course, useless; it will simply flap in the wind.

And so, when the bow of our yacht looks straight into the wind, and the sail “rinses”, then this position will be called leftist. In this position, the sails, of course, cannot work, and the yacht will simply be blown away by the wind, which (blowing directly at the bow of the vessel) is most often called “nasty.” Often, the left-hand position is mistakenly called the heading. Of course, this is incorrect.

A sailing yacht cannot go straight against the wind; it has to tack, that is, go to the intended goal in a zigzag manner. This means changing the tack periodically. Either sail on starboard tack when the wind is blowing to starboard, or on port tack, respectively, when the windward side is port.

Screenshots from e-regata.com

A good cruising sailing yacht, can sail at an angle to the wind of 40-45 degrees (sports - up to 30). This is an “acute” course, which is called sharp close-hauled. At the same time, the sails are practically on the verge of stripping.

The result of all the forces acting on the yacht, where the most important component is the traction force of the sail, allows us to move forward. The resistance of the aquatic environment, on the one hand, is a serious obstacle, and on the other hand, it is a force that helps us fight drift. Of course, in a flat-bottomed boat, the drift will be so great that the sail, in this case, will practically only work to demolish the vessel.

On such sharp courses, the effect of a wing appears in a properly sewn and tuned sail.

The minimum angle to the wind is the tacking angle at which the yacht is able to continue moving, depends on its aerodynamic qualities, but as the angle decreases, one way or another, there comes a moment when the drag force of the yacht exceeds the lifting force of the sail.

This means that the total angle of 60-90 degrees will be the so-called dead zone, and to change tack, it is necessary to gain sufficient speed so that the bow of the yacht has time to pass this sector. If there is not enough inertia to turn, the ship will get stuck in the left-to-left position.

The turn itself, at which the bow of the vessel will cross the direction of the wind, is called tack.

Let's return to courses relative to the wind. Let's assume that our sailing ship is sailing on port tack, with a course relative to the wind, sharp close-hauled. If the yacht intends to make a 180-degree turn clockwise and set on the opposite course, then, falling (increasing the angle relative to the direction of the wind), or, as they also say, descending into the wind, it will first pass the course full close-hauled and will set course Gulfwind.

In this case, the wind will blow at an angle of 90 degrees to the centerline plane (DP) of the vessel. More often, such a course of a yacht is called half the wind.

If the yacht continues to fall away, taking a little more to the right, then it will go on course backstay, relative to the wind. By analogy with close-hauled, the backstay course can be steep and full. And although drag, no one has canceled it, on this course, the sailing yacht will develop the highest speed, with minimal drift, and the angle of attack of the sail increases significantly.

To make a complete turn, our sailing yacht only needs to pass the “fair wind sector” when its direction coincides with the direction of the ship’s movement. At this moment, the yacht will be heading jibe.

It would seem that the sail was set perpendicularly direction of the wind, raised the spinnaker, and the yacht took off. No. Firstly, it will not rush; this course is inferior in speed to the backstay. Secondly, only owners of straight sails with yards can relax. In the case of our Bermuda grotto, constant monitoring of it, the wind and the course is necessary.

With strong excitement, it becomes more difficult to stay on course. This can lead to the boom spontaneously throwing over to the other side, which can lead to serious damage. And on dinghies - with an overkill. One of the signs that this is about to happen is the rinsing of the luff of the mainsail, i.e., along the mast.

A gybe turn, that is, when the yacht crosses the direction of the wind with its stern, is not exactly the most difficult, but requires very fast and coordinated actions of the crew.

After all, it is necessary to have time, almost completely, to select the boom sheet, at the moment the boom passes the DP to the other side, and give up the windward backstay, if there is one. And, immediately, do all this in reverse order.

As the wind increases, the situation, of course, becomes even more complicated, and in squally winds, it is better for inexperienced yachtsmen to avoid the jibe course altogether.

After passing the jibe sector, all that remains for the yacht to do is to bring itself much closer to the wind (to rise upwind), i.e., now to reduce the angle between the wind direction and the ship’s DP. At the same time, the yacht will again take the bagstay course. Only the windward side, now, will be starboard, and the boom will lie on the left side. The yacht made a 180-degree turn and set on the opposite course.

The tuning of the sails, on any course, plays a decisive role in their performance. This, of course, is the topic of a separate article, but the stronger the wind, the less “potbellied” the sail should be. Its efficiency, roll angle and drift amount directly depend on this. Moreover, in weak winds, everything is exactly the opposite. The drift angle is quite easy to calculate: this is the angle formed by the wake and the yacht’s DP.

Also, do not forget that the sails are always adjusted relative not to the true wind, but relative to the apparent wind, that is, the one that is felt on moving objects. But we will return to all this later in the general theory of sails.

Mikhail Safronov, for the magazine website

Depending on which side the wind blows from, the course of the starboard and port tacks is distinguished. Wind courses have their own names:

Leventik- a course that forms an angle of 0° with the wind direction, that is, the wind blows almost exactly in front of the ship. Since a sailing ship cannot follow such a course, they usually say not “course”, but “left-hand position”.

Fordewind- a course in which the wind is directed towards the stern of the ship. They say about a ship going into a jibe that it is “going with full wind.” The angle between the wind direction and the center plane of the vessel in this case is about 180°.
1. Fordewind is the same “fair wind” that sailors desire, although in sailing this course is by no means the fastest, as one would expect. In addition, it requires attention and skill from the helmsman to control additional sails (usually a spinnaker). In this case, the sail is placed perpendicular to the direction of the wind, the thrust on it is created mainly due to the direct pressure of the wind on the sail. Light wind on this course is practically not felt, since the speed of the apparent wind is equal to the difference between the speed of the true wind and the speed of the oncoming air flow.
2. A jibe is one of two turns (a turn is a change of tack) of a sailing vessel, in which the direction of the wind at the moment of the turn passes through the stern. For ships with an oblique rig, a jibe, in contrast to a tack, is more complex and, at times, dangerous, requiring precise actions by the crew when working with the sails. It is no coincidence that the command is given with the clarification: “Prepare for a jibe!”, whereas during a tack the commander simply commands, “Prepare for a turn!”

Gulfwind, or half-wind - a course at which the angle between the direction of the wind and the direction of movement of the vessel is about 8 points (about 90°). On this course, the wind blows perpendicular to the ship's port, and the apparent wind is directed from the bow at an acute angle to the ship's port. Accordingly, the sail is installed at a lower angle of attack, its thrust is equal to the longitudinal component of the lift force, and the drift force is equal to the transverse component. On this course, the sail should divide the angle between the DP and the direction of the apparent wind approximately in half.

Backstay- a course that forms an angle with the direction of the wind of more than 8, but less than 16 points, that is, the wind blows from the rear and side in relation to the ship. Highlight the course full backstay, at which the angle exceeds 135° degrees, that is, approaching jibe, and cool backstay(less than 135°). The sail is set at an angle to the wind. Usually on this course a sailing ship develops its highest speed. In the backstay, the sail operates at a high angle of attack, at which wind pressure plays a major role in creating the thrust of the sail. There is virtually no drift force.

Beidewind- a course at which the angle between the direction of the wind and the direction of movement of the vessel is less than 90° (less than 8 points). Close-hauled wind full And steep. Different sources draw the boundary between them in different ways (in the range from 45 to 67.5°). The thrust of a sail when close-hailed is entirely determined by its lifting force; with increasing wind pressure, the thrust force decreases, but the drift force increases. Thus, on this course the sail, installed with a minimum angle of attack to the apparent wind (5-10°), works completely like an aerodynamic wing. The best sailing ships sail at an angle of 30-35° to the direction of the true wind. Due to the addition of the wind speed vectors and the oncoming air flow, the apparent wind speed on a close-hauled course turns out to be maximum, as well as the lifting force on the sail, which is proportional to the square of the wind speed. The drift force also reaches its maximum value. If you try to sail at a sharper angle to the wind, the speed of the vessel will decrease, the sail will begin to flap, the lift will decrease and, finally, a moment will come when the drift and resistance of the water to movement will far exceed the thrust. The ship will lose speed.