5个不对称球帆加速操作.docx

5 KEYS TO ASYMMETRIC SPEED AND TEAMWORKTHE REIGNING J/80 WORLD CHAMPION DETAILS HOW HE MAKES HIS SPRIT BOAT GO FASTER OFF THE WIND THAN THE COMPETITION.ByKerry KlinglerpostedMay 1st, 2002 at 12:00am35Want to get more speed out of your asymmetric spinnaker and become more comfortable racing with this type of sail? Its worth remembering, first off, that all your knowledge of speed with traditional symmetric spinnakers isnt wasted when you get on a boat with an asymmetric. Several premises have proven to be fast under either kind of chute.At the top of your list is pulling the rig forward when sailing downwind. This alone can have a huge effect on boatspeed because it projects the spinnaker away from the mainsail into clearer wind. Ease off your backstay for starters. You might want to sight up your rig after easing it to ensure that you dont ease it so much that you create reverse fore-and-aft bend (we call this inverting the rig). In most boats, youll find you can ease the backstay a lot before this happens.To get the rig farther forward still, use your jib halyard to pull the rig forward. After the jib or genoa comes down, the bowman hooks the halyard to the tack fitting and grinds the rig forward. Youll be amazed how much farther forward the rig will go. On boats that use roller-furling systems on their headsail, you cant use the jib halyard for this, but after you furl your headsail, you can tension your jib sheets, which will pull the slack out of your headstay and cant the rig forward. On my J/105, I ease the backstay to the point where its very slack, then tension both jib sheets. This moves the top of the rig forward and snugs up the backstay.The second important technique to maximize downwind speed (which also applies to all types of spinnakers) is to trim your sails to further increase separation between spinnaker and mainsail. The trimmers goal should be to ease the sheet as much as possible, allowing the spinnaker to lift and float away from the main. On boats with asymmetrics, heeling the boat to windward also helps the spinnaker separate from the main because it projects the luff to windward of the boat. This is why you see the top boats in an asymmetric fleet sailing downwind with the whole crew packed to weather.The third key is to pay attention to the trim of the spinnakers tack line. I often wonder why racers with symmetric chutes constantly adjust the topping lift, but then, with an asymmetric, forget to do the same with the tack line, since adjusting it has a similar effect. If the luff of an asymmetric becomes too bouncy or hard to control, tighten the tack line. This straightens the luff and moves the draft forward in the sail, and settles it downwhich is why I like to have the tack line a little tight for a set or jibe because it fills more quickly.HOW TO POINT, FOOT, AND SHIFT GEARSSHIFTING GEARS ON A BOAT IS ONE OF THE MOST DIFFICULT ASPECTS OF SAILBOAT RACING AND REQUIRES A KNOWLEDGE OF YOUR BOAT, THE CONDITIONS, AND PLENTY OF PRACTICE. GREG FISHER BREAKS DOWN HOW TO FIND THE BASELINE, AND THEN SHIFT GEARS TO GET YOUR BOAT GOING FAST IN ALL CONDITIONS. FROM THE SW ARCHIVES, OUR JUNE 1998 ISSUE.ByGreg FisherpostedJun 3rd, 2002 at 12:00am17SHIFT GEARS 1STUART STREULISubtle gear changing is what truly separates those with just adequate boatspeed from those who always seem to be a click quicker and higher. While most of the fleet starts the race with a similar setup, created with the help of a tuning guide or by following standard principles, the fast boats are constantly making additional adjustments. When conditions suddenly changea puff hits, or powerboat waves arrivethese sailors shift gears smoothly. Before we dive into the subtleties of their sail adjustments, lets take a look at how you might create a basic pre-race setup.Step 1: Set the depthTry to memorize the depth that feels about right in 10 knots of breeze. Then set your mast bend and headstay sag to replicate that shape, using it as your starting point in other velocities. Another method is to increase mast bend until you just begin to see slight wrinkles (called inversion wrinkles) running from the clew of the mainsail to the lower quarter of the mast. For the jib, decrease headstay sag until you are just able to make the telltales on both sides of the sail fly easily. Any tighter, and the steering groove will become too narrow.Step 2: Set the draft positionFor most boats, the main draft should be positioned nearly halfway back. Pulling the cunningham tighter pulls the draft forward, while easing it allows the draft to move aft. Use the jib halyard or jib cunningham to position the fullness in the jib. The draft should be slightly farther forward than in the main, usually about 35 percent, or roughly one-third, of the way back.Step 3: Set the twistTo set the leech tension for the main, sight from under the boom and set the sheet so that the chord of the top batten is parallel to the boom. For the jib leech, set the sheet so that the last 6 inches of the middle of the leech (a mid-leech batten helps here) are parallel to the centerline of the boat. Easing the sheets allows the outboard end of the battens to fall away, increasing twist. Trimming the sheets does the opposite, decreasing twist.Step 4: Set the angle of attackIf you drop the tiller, the boat should continue to track straight, or slowly head up into the wind. Any more helm than that means excessive rudder drag. If the boat has excessive windward helm, ease the traveler to until the helm is balanced. This four-step process for setting your sails is only a starting point. Its still a great idea to line up with someone you know is fast before the race to see if you are on the money. If youre faster, great! If youre off the pace, just ask your crew, Are we lacking speed or pointing ability?Solving Pointing ProblemsAn inability to hold a lane or position close to other boats can really destroy a tactical game plan. Pointing problems are not so much indicated by the angle that the boat seems to be sailing relative to the boats around us, but more by the fact that the boat is actually sliding to leeward.Trying to pinch to maintain height can be the crux of the problem. The old adage, foot, then point, says a lot. A boat needs to go fast before the underwater foils can develop enough lift to hold their position in the water. To regain pointing ability, ease the sails out, bear off slightly, and get back up to speed. Once up to top speed, re-trim to your starting point trim and reevaluate your pointing problem. If the problem persists, check your sail trim.When sail trim is the cause of the problem, its usually the main, not the jib. The upper leech of the main provides most of your pointing ability. Be sure to trim the main so the upper batten is at least parallel to the boom. If you need more pointing ability, try trimming the main tighter. You can hook the upper batten as much as 15 degrees to weather for short periods. Avoid the temptation to overtrim the jib to help pointing ability. Hooking the jib leech will choke the slot between the main and jib, stalling the entire sailplan. The jib should never have less twist than described in the basic setup.Only after youve decided to trim the main harder should you try to pinch the boat. In this mode, the weather telltales on the jib will be stalled. In big puffs, the luff of the jib can break as much as 8 inches back. This super pinch mode can only be held for short bursts and in flat water. Once the boat starts to slow down, be sure to ease the sails out, regain your speed, then start the process again.While it may seem natural to let the boat heel more when trying to point, fight the urge. Keeping the boat flat will help maintain a balanced helm and maximize the efficiency of your underwater foils. Still not pointing? Either your rig is too loose, resulting in too much headstay sag (i.e., the jib is too full) and sometimes too much mast bend, which makes the leech too open, or the luff tension on either sail is too tight (the draft is too far forward).Solving Footing ProblemsWhat if your pointing is fine, but your straight-line speed is lacking? The simplest fix is easing the sails. More open leeches on both sails will help the boat sail lower and faster in a straight line. Sometimes, however, this results in a pointing problem. If so, first check your helm balance. Weather helm can seriousIy hinder the boats ability to go fast. Instead of easing sheets, its often better to find a way to ease helm. First, try to sail the boat more level. If you cant keep the boat flat, induce more mast bend to flatten the main. The next step is to ease the traveler until the helm is balanced. Finally, tighten the outhaul, tension the cunningham/jib halyard to pull the draft forward and open the leeches of both sails.*Gear Shifting: Puff On! *Weve got you going with good speed and good height. Then what happens? The wind velocity changes and its time to shift gears. First, lets look at some of the automatic trimming change that should happen as soon as a puff hits. 1. Ease the main, and sometimes the jib 2. Steer up to feather the boat 3. Re-trim sails.Since a puff typically lifts you, due to a change in the apparent windspeed, you need to ease sheets and head up as it hits. Be sure to let the boat climb up into the wind and steer toward the upper end of your groove with the jib luff actually breaking. In flat water, all that may be required is a quick ease of the mainsheet. But in chop, it may be necessary to ease the jib as well.If the puff packs some real velocity, more adjustment may be necessary. If you cant hold the boat down, and theres still too much helm, try the following, one at a time, until the helm is balanced. 1. Ease the traveler 2. Bend the mast (vang tension, backstay tension, etc.) 3. Tension the cunningham on both main and jib.Gear Shift: Into a LullFor the same reason that puffs are lifts, lulls usually appear as headers. In a lull, its important that you bear off as smoothly as possible. Make sure the boat remains flat and resist the temptation to add heel to maintain feel in the helm.Ease the main so the top batten angles outboard from parallel to the boom. Leave the jib trimmed initially until the bow is pulled down to the lower end of your groove with both telltales streaming aft. At that point, the jib should be eased so the leeward telltale doesnt stall.Heres how to maintain speed in a lull. 1. Ease the main 2. Allow the boat to heel to weather, creating lee helm, to steer the boat down 3. Ease the jib 4. Level the boat 5. Pull the traveler up (if the boom is below centerline).If the lull is long-lived, you may need to take additional steps to maintain speed. 1. Straighten the mast and induce luff sag in the jib 2.) Ease main and jib cunninghams to maintain correct draft position. The smoother you shift gears the faster youll be, so practice until its automatic. Heck, manual transmissions went out years ago!TAGS:PETER MCGOWANITS EASIER TO SAIL FAST AND LOW BY EASING THE TACK LINE, HEELING THE BOAT TO WINDWARD, AND PROJECTING THE LUFF OF YOUR ASYMMETRIC TO WINDWARD.After we build speed and the pressure increases in the sail, we usually try easing the tack line to allow the chute to float away from the main and rotate to windward. I like to call this effect on an asymmetric opening the luff. When the luff opens and the sail lifts away from the boat, the upper sections of the luff are more pressured, and the luff flattens in curvature slightly. This is OK, because the spinnaker has pressure in it and remains stable while rotating to windward more and separating from the mainsail.Heres a general rule for tack-line tension: if the tack line is angled to leeward or if the luff of the sail becomes unstable, tighten the tack line; if the tack line is angled to windward and you want to try to open up the upper luff, ease the tack line.The fourth important factor in downwind speed with an asymmetric is how you trim the mainsail. The primary rule is to avoid overtrimming the main. I check the trim simply by easing the main until the luff starts to break and then bring it in until it stops breaking.Vang trim is also important: On our J/105 at the Sailing World NOOD at Larchmont, N.Y. (our first regatta in my new boat), we were slow downwind. I couldnt figure what the problem was until we experimented with the vang tension, picking up speed by easing it more than we normally would aboard a boat with a conventional spinnaker.Weight placement is also important, and as I said before, the key move on our boat is to position the crew to windward to project the spinnaker. At the same time, we focus on our fore-and-aft weight placement. Several of the J Boats designs have very full bows and like the weight forward downwind. Ive also found this to be fast in a lot of other boats. In Stars and Etchells, for example, you often see a crewmember in front of the shrouds. The goal in weight placement is to reduce wetted surface, but not to plow the bow too much or lose control. In a Laser, keeping your weight forward is fast, but you risk losing control and getting wet.The fifth factor that makes all the difference in speed downwind with an asymmetric is organizing your crew as a team. When sailing the J/80, each crewmember covers a key position, but on a larger boat, you can divide your crew to cover the same four areas.The first position is that of the spotter/tactician, whose job is to help with the following critical decisions: First, the spotter keeps us all informed about the position and speed of our competition. Second, he provides me, the skipper, with information about our boats speed and angle relative to a specific boat or group of boats. Hell say whether were lower or higher in angle and whether were faster or slower. The spotter also helps with tactical decisions, such as how to keep our lane clear and free from any wind shadows, and how to take advantage of windshifts or different sailing angles coming into the leeward mark.The second position is that of the spinnaker trimmer, whose main job is to help the skipper sail the boat at the optimum sailing angle for the best VMG to the leeward mark. The trimmers goal should be to keep the sheet as eased as possible without the luff of the sail breaking. An equally important job is to constantly inform the skipper of the pressure on the sheet and in the sail. I find the trimmers advice most helpful when he repeatedly suggests how much or how little pressure is in the sail. He might say, for example, Im losing pressure on the sail, lets try a little higher, or I have a lot of pressure, lets fall off a little. On bigger boats, the trimmer position becomes a team effort, with the grinder and trimmer working together to keep the sail in optimum trim while communicating with the helmsman.On asymmetric boats, being ready to jibe at any time is the key factor in attacking the racecourse. The third crew position is that of the No. 2 trimmer, whose job is to be sure that were ready as soon as the previous maneuver is completed. This includes the following: 1. the current spinnaker sheet must be free to run out smoothly and completely; 2. the second trimmer, on the new sheet, must be in a place from which the new sheet can be trimmed efficiently and quickly; 3. the new spinnaker sheet is clear of the bow pulpit and high up on the headstay (around 6 to 8 feet up is best), ready for a fast trim.During the jibe, the spinnaker trimmer working the old sheet stays with that sheet. His job is to make sure the clew floats to the headstay and then to be sure that the pressure is off his sheet so the new sheet can be trimmed rapidly on the new jibe. The second trimmer pulls in as fast as possible on the new sheet in an effort to refill the spinnaker quickly. Right after the spinnaker fills, hell normally ease it again to set the trim properly on the chosen angle for the new jibe.The fourth job is the skippersto sail the boat to the fastest VMG to the leeward mark. Its his job to assimilate the information given to him by the trimmer and the spotter. Some skippers delegate the tactical decisions to the tactician; others make those decisions for themselves. What counts is that boatspeed and VMG are maximized while at the same time, the skipper defends the boats position on the racecourse.In summary, we work together as a team to get the boat down the run, just as you would with a symmetric kite. The skipper looks for constant feedback from the others. The trimmer focuses on angle assessment and pressure on the sail. The second trimmer makes sure were always ready for the next move. And the tactician and spotter help keep the boat in the best position relative to our competition and the next mark.Here are a few other simple but important downwind tips: Before a race, get out early to develop a good idea of the conditions and wind angles upwind and downwind. When going into a windward mark, ask yourself if youre on a lift or a header. That will help you decide which tack you want to take down the runtypically, the headed jibe. And use a hand-bearing compass to help sight the leeward mark and then determine when to jibe.Work hard to keep your air clear and avoid sailing under the fleet; in asymmetric boats its easy for boats behind to trap you and blanket you. And when you jibe, try to make every one of them count. Each jibe results in a loss in distance, so while you should take advantage of the shifts, dont jibe just for the sake of jibing. In a J/105 on a 1.5-mile leg, two extra jibes will cost you at least four boat lengths.My final thought on asymmetric boatspeed and teamwork is that you shouldnt be afraid to practice a