The events in Odessa at 28 November 2020

Jib setup

28 November 2020, 11:00
category: master class
place: The yacht club Seaport (Primorskaya street, 6)

The jib is tuned first, as the main traction sail, operating in an undistorted air flow. But first, let me remind you that when tuning sails, you set them at a certain angle to the wind and are working on three important characteristics that determine the sail profile: twist, sail depth (belly) and belly position. Well, let's start customizing the genoa. But first we need to know: how is the staysail set up, what tools are used for this? 1. Jib-sheet (the degree of its tension) The sheet largely determines the pitch of the sail. The selected sheet is a smaller angle, the etched sheet is a larger angle. But not only. It can be used to influence both the twist and the belly. The sheet is the main tool for adjusting the head sail. 2. Jib-sheet carriage (its position) The position of the carriage of the jib-sheet is responsible for the twist of the jib. The general rule is that by moving the carriage forward, we decrease the twist ("close the sail"), and by moving it back, we increase the twist ("open the sail"). 3. Jib halyard and forestay (degree of tension) With the help of these two, the "belly" of the sail and its position are adjusted. Moreover, the forestay is mainly responsible for the size of the "belly", and the jib-halyard for its position (front-back). Someone will say: what about the staysail sheet? He also regulates the belly ... Well, let's add here the staysail sheet. But remember that its tension only affects the sail depth in the lower third!The first time you don't figure out what is responsible for what. It would be nice to have some kind of dashboard. He looked at the instruments and corrected what was needed! In the role of such a dashboard, "sorcerers" act: light ribbons that are attached on both sides of the staysail along the luff, at 15-20 times the length of the rope. Airflow indicators, tell-tailes Usually they are made in different colors (for example: red and green) and fastened so that the green ones (for example) will be slightly higher than the red ones. Then, in the counterlight, they can be distinguished not only by color, but also by position. If the air flow is free of turbulence, all sorceresses will flow horizontally. On properly set sails, sorcerers can lift slightly, especially in strong winds. If the windward sorcerers are bent - the angle of attack of the sail by the wind is too sharp, you are going to the wind too steeply. In this case, you need to either fall off, or (without changing the course) pick up the sheet. If the lee sorcerers are bent, you are walking too full, the air flow is torn off the sail, the sail does not work! You must either lead or (without changing course) veer off the sheet. And now we are moving on to what, in fact, we will tune with instruments with the help of these very sorcerers. And our conversation will go about the shape of the staysail, namely about its three parameters: angle to the wind, twist and belly.Where to start setting up the jib? With a twist? From the corner? Or maybe from the belly? Probably, everyone has their own order of settings, and it can hardly be said that there is any strict rule. I start by basically setting the head sail angle to the wind, focusing on the middle of the sail, then twist and finally belly. All the same, as practice shows, this is not a once and for all verified, sequence. So, for example, after setting the twist, the jib angle is corrected. Headsail angle The optimal angle of installation of the sail to the wind is achieved by choosing or yielding the staysail sheet. But how to determine the optimal angle already or not yet? We use the wizards already familiar to us. With the correct sail angle to the wind, all sorcerers will stream horizontally. On sharp sidewind the course adjusts to the sails (sailing course): Why are we heading for sails on racing sidewind? When we go too sharply, we cannot adjust the sails (for example, we cannot fill the sheet, because the sail "knocked into the board" will stop working altogether). In this case, you need to adjust the course: The windward sorcerers bend and sway - too sharp - bear down; The leeward sorcerers bend and sway - too full - be presented.If you want to go as steep as possible, i.e. to go out to the wind as much as possible, then you need to work at the rudder all the time: when the wind increases (in gusts), the boat needs to be brought (“pressed down”) to the wind, and when the wind weakens, you need to roll back slightly. In principle, adjusting the head sail angle on a racing side haul is a simple matter. Bring and tune the sails so that the windward sorcerers rise slightly upward. To do this, be brought to the brink of rinsing the staysail (the windward sorcerers are bent upward almost vertically), and then roll a little. When accelerating on a sharp course, the windward sorcerers should rise slightly from the horizontal position. This is normal. If your task is to achieve maximum speed, and the course is not decisive, achieve a state in which the sorcerers will be located horizontally. At full hauled, the sails are adjusted to the chosen course (sails on the course): The windward sorcerers bend and hesitate - too sharp - pick up the sheet; The underwired sorcerers bend and hesitate - too full - turn the sheet. In the diagrams, you saw the ideal picture when all three pairs of witches react to our actions in the same way. In reality, such an ideal "witchcraft" most likely will not exist. But, as I already said, at the first stage we "in the rough" install the staysail and will focus on the sorcerers located in the middle part of the luff. It is their behavior that maximally reflects the property of the air flow near the sail surface.Jib twist Having adjusted the pitch of the staysail, proceed to adjusting its twist. Let me remind you that only at the optimal angle of attack of the wind (wind flow), the maximum aerodynamic force is created on the sail. And, of course, this angle of attack should be the same over the entire sail height. The twist (twisting of the sail in height) is just needed in order to ensure the same angle of attack by the wind along the entire height of the sail. You haven't forgotten that the apparent wind increases with height and changes its direction? At the bottom it is sharper and slower, at the top it is fuller and stronger. (Lecture 02, Lesson 1 "Wind and the basics of sail theory"). And, therefore, the pitch angle of the sail must also change with height: from a smaller angle at the bottom to a larger one at the top of the sail. And now we can talk about setting the sail twist (twisting it vertically). Before starting the tuning of the genoa twist, it is necessary to set the jib-sheet carriage in such a position on the pursuit so that a straight line passing through the sheet would divide the luff of the sail approximately in half. If you are going to tune the twist right after the turn, then it is logical to place the jib carriage for the new tack in the same position as the already tuned carriage. On their own boats, before installing the staysail, they lay it out on the berth, beat off a line from the clew to the middle of the luff and glue a bright tape half a meter long to it. After the staysail is raised, this tape makes it easy to visualize the position of the sheet.So, we set the carriage to the starting tuning position. And immediately we begin to follow the "dashboard" - the wizards. They will tell you: is everything okay with the twist? Twist too big (excessive twist) This is what an excess twist looks like on a genoa. See how its upper part "fell off" into the wind, and practically does not work. If you look at the sorceresses now, you will notice that the upper windward sorcerer is rinsing. This is a sure signal that the sail is too much twist. Try to move the carriage forward a little and then pick up the jib sheet. The sheet will be at an angle that will allow it to pull the leech down. The leech will tighten and the twist will decrease. By moving the carriage, make sure that the windward sorcerers work equally across the leech. Just don't overdo it.  Twist too small (insufficient twist) The situation is different here. The staysail sheet carriage is too far forward for a sharp course. As a result, the leech is overtightened, the upper part of the sail “closed”, and a “lip” (excessive belly) formed on the lower luff. The sail does not work well in the lower third and this is signaled by the flushing lower windward sorcerer.So, you need to move the carriage back and slightly release the sheet, increasing the twist. The clew will rise, the leech will tighten, the leech will loosen, and the top of the sail will slightly wind down. The twist will follow the course and the wind will run at the leading edge of the sail at the same angle of attack. You can draw a line under the twist settings. The staysail twist is regulated by changing the position of the jib-sheet carriage and, in part, by the degree of tension of the jib-sheet itself. Strictly speaking, adjusting the twist on the staysail is about balancing the tension between the leech and the leech. Indeed: if our leech is too stretched, then the sail is "closed", the twist is too small, and if we pull the leech too much, the twist will be excessive and the upper part of the sail will "fall off" into the wind. The general rule of thumb is: • уIf the upper part of the sail has "fallen off" under the wind, then the leech is too loose, the twist is excessive, the carriage must be moved forward; • If the luff is “loose lip”, then the twist is insufficient, the sail is “closed” and it is required to move the jib carriage back. And I will add that it is better to have a slightly more twist than a crushed sail. Almost always. Staysail belly Well, now we got to the belly settings. Let me remind you that the belly is determined by two parameters: depth and its position (front, middle, back).A full, pot-bellied sail provides good traction (but also increases drift and roll). It is good to have such a sail in a light wind, or on a wave. Flat sails are good in strong winds and smooth water. But no less important than the belly itself is its position, determined by the distance from the leech to the maximum sail depth. To a large extent, the position of the belly also determines the shape of the sail entrance: flat or round. So, for example, displacement of the belly forward (round entrance) increases the lifting force of the sail and the sector of efficient sail operation without changing the sail settings (heading sector). But you cannot sail as sharply as possible with such a sail. And vice versa: displacement of the belly slightly back (flat entrance) of the sail allows you to go very sharply, but in a narrow course sector. You can adjust the staysail belly and its position using: 1. Pulling or loosening the forestay; 2. Tightening or loosening the staysail halyard. Forestag is largely responsible for the depth of the belly (in the upper and middle parts). In order to flatten the sail and reduce the belly, you need to fill the forestay. In order to enlarge the belly, the forestay must be loosened. There is another tool that can be used to influence the size of the belly. This is a sheet. By poisoning it, you can enlarge the belly and vice versa, stuffing it, we reduce the belly. However, it must be remembered that the sheet can only adjust the belly in the lower third of the sail. Adjusting the position of the staysail belly is essentially reduced to working with the leech.We pull the luff - the belly shifts forward, weaken the luff - the belly goes back. A head halyard is used to tension the luff. Well, now you have an idea of ​​how, in principle, to tune the "belly" of the sail. The diagrams show how you can “play” with the belly settings in different wind-wave conditions. 1. The yacht was sailing on calm water with a fairly fresh wind (14-16 knots). On calm waters with good winds, the forestay and halyard should be full. But after a while the wind dispersed a high wave and we are now interested in the thrust of the sails. To increase thrust we decrease the forestay tension, correspondingly increasing the sail depth and making the entrance round. But at the same time, due to the weakening of the forestay, the belly moved too far forward. If we turn the rope a little, then the belly will go back to the amount we need. 2. We walked on a small wave with a weak sidewind (3-4 knots). After some time, the wind increased to 12-14 knots, the wave became higher. In response, we flattened the sail by filling the forestay. But at the same time the belly moved back. To return it to its previous position (we need a wide exchange rate sector, which means a round entrance, belly a little forward), we fill the halyard. On calm water with light winds (when a sail with great depth is needed), the forestay tension should be about 30% of the maximum, and the belly should be approximately in the middle or even slightly behind (55%).In difficult wind and wave conditions, it is better to loosen the headstay in order to obtain a round sail entry and give it a "thrust". In addition, this will make it easier to correct the course of the boat in waves without slowing down the sail (large heading sector). Remember! • If you loosen the forestay tension, you must also loosen the jib halyard so that the sail's belly does not move too far forward. • Be careful! Do not fill the halyard if the sheet is pulled tight!

The poster of the event — Jib setup in The yacht club Seaport