Achieving Proper Balance
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Achieving Proper Balance Arvel Gentry continues his discussion of sail adjustments on the wind By Arvel Gentry SAIL Magazine December 1973 Last month I discussed a systematic procedure I have found mast farther aftuseful in helping me achieve proper mainsail and genoa trim I If the boat turns sharply to windward when you release thedescribed how the telltale system in Photo 1 and the tuft system tiller then you have too much weather helm Try moving thein Photo 2 are used to achieve a good basic trim for the two sails crew aft and to the weather side and ease December the mainsail1999 travelerBut good windward performance depends not only upon basic down until only a moderate amount of tiller pressure is requiredsail trim but also on boat balance having just the right amount of to keep the boat going straight If you still have too much weatherweather helm helm try leaning the mast forward Last month we saw how to use the telltales and tufts to Once you have the boat in reasonable balance turn yourachieve the basic sail trim settings Once you have these settings attention to the genoa The trim of both sails might look about assail to windward with the first lee side tuft T1 in Photo 2 they do in Photo 3 Examine the leech of the genoa and the curveshowing just a slight amount of agitation Let the tiller go and of the mainsail in this picture You will see that the distancewatch the boats movement If the boat starts to head up slowly between the genoa and the main increases from the spreaderinto the wind the boats balance probably is good down to the boom and the shape of the genoa leech does not If it heads off instead you have what is called lee helm and it follow the mainsail shape as it should With smooth watershould be corrected before going farther First try moving crew conditions this is a good time for a barber haulweight forward and to leeward in light air If possible lean the To rig a barber haul hook a line to the jib clew with a shackle run it across to the windward winch and pull the clew into the boat As you do this ease off on the genoa sheet to maintain the same distance off at the spreader This easing will create more twist and camber in the sail but the fixed distance off the spreader can be maintained The boat now should not only point closer to the wind it also should keep up its speed What we have done with the barber haul is to get a better method of controlling the total shape of the genoa With a barber haul you may have to move the jib fairlead a bit forward to get the desired leech shape in the genoa After all this is completed check genoa telltale 3 Photo 1 If you barber haul too much this telltale will twirl As you barber haul the genoa in you also may have to move the mainsheet traveler to windward more and ease the mainsheet at the same time to maintain proper attached flow all up and down the mainsail If the genoa hooks in sharply at the leech first check the leech line Let it out until the leech shakes then tighten it just until the flutter stops Also increase the jib halyard tension This will ease the leech so that the air gets a straighter run from the sails midpoint to the leech Photo 4 shows the sail with the barber haul set When to barber haul and how much are difficult questions to answer Basically the barber haul should be adjusted so the leech Photo 1 Telltale and tuft arrangement Photo 2 Tuft system Photo 3 Without barber haul Photo 3 With barber haulof the genoa follows the curve of the mainsail But there will be sail trim table and make the necessary adjustments While thistimes when the genoa should be trimmed tighter and other times relieves the helmsman from constantly worrying about sail trimwhen it must be moved farther outboard But when and how he should however check the sail trim himself occasionally andmuch suggest any necessary changes One useful approach lies in the axiom know thy boat By Never feel bound to a sailtrim chart if you think a trimthis I mean you should have a very good idea of what boat speed change might improve speed under new sailing conditions Ifyou should be able to achieve at different velocities of apparent you do make a change though have the crew make a note of it sowind I call this maximum windward speed and it is obtained by that the trim chart can be revised In this way your learning fromrecording apparent wind speed and boat speed readings when past experience will be in smooth water conditions A large collection of these All this sailtrim discussion has been for moderate winds ofdata points can be plotted boat speed versus apparent wind 10 to 12 knots In light airs you need every bit of sail drive youspeed and a smooth line drawn through the highest points can get Slack off the halyard and the backstay if you think youHowever it is important that each point be an honest data point need more sail camber Also keep the genoa farther off thethat is that the boat be sailed at the apparent wind angle and with spreader Exaggerate the forward location of the genoa car insail trim settings that you feel give the best speedmadegood to light airs Barber haul with care and watch telltale 3 If it twirlswindward As you learn more about your boat and how to trim its barber haul it only if it definitely gives increased speed orsails this maximum windward speed curve should of course be pointing abilityrevised Never try to point too high and always keep the boat moving When the water is smooth and the boat has reached its Frequently check for lee helm and if it occurs in light windsmaximum windward speed in moderate 1012 knots try the shift crew weight forward and to leeward Lee helm in light airsbarber haul But first sail close hauled without a barber haul for a can be very bad for you will generate excessive leewayfew minutes and observe the average speed Write both the boats All these light air comments are pretty standard but as Stevespeed and the average wind speed down Now barber haul the Colgate pointed out SAIL October 1973 too much sailgenoa in and watch boat speed camber can be a bad thing in very light air The reasons revolve If boat speed does not drop then obviously you should be around the way sail pressures change with camber and the waybarber hauled for this wind and sea condition If the boat speed boundary layer reacts to pressure and low air speedsdoes drop you must now determine if the closer pointing angle In general increased sail camber means there will be aachieved is offsetting the speed reduction More testing is decrease in the suction pressure from the forward part of the leerequired side of the sail as one moves aft increasing pressure In When the wind and chop increase and the boat cannot reach addition the boundary layer is more prone to separation as airmaximum beating speed the barber haul will have to be eased speed gets lower This means that increased camber at low windoff to get speed back up speed may give you a difficult leech separation problem When In light winds you need more camber in the genoa and you this happens the leech telltales on the main 10 12 and 14 inshould ease the sheet This however moves the sail farther from Photo 1 and the genoa 3 4 6 and 8 will start to twirlthe spreader and the ability to point goes down Check boat If the telltales do twirl the sails have too much camber Onspeed and slowly barber haul the clew back in to see if you can the mainsail tighten the outhaul ease the sheet off a bit andget back some pointing ability without losing too much speed move the traveler to leeward to see if you can get the unseparated flow on telltale 3 is going to be telltales to lie down On the genoa tighten up on the backstay difficult under these conditions halyard and move the clew outboard Remember a flat sail At this point you should have both sails trimmed fairly well without separation usually is better than a fuller sail that hasNow check both the knotmeter and the apparent wind speed and leech down the values All further sail adjustments should be When the wind gets high you do have to start carefully with a close watch on the knotmeter Try A tight backstay and genoa halyard are very important Move thechanging the genoa distance off the spreader and watch boat genoa car aft and barber haul it if maximum beating speed stillspeed and pointing ability This is a very important parameter can be maintained when it is hauled in Mainsail trim in heavyand careful testing is required to find the optimum distance for winds is primarily a matter of controlling weather helm and heeleach wind and sea condition angle Always record exactly how the sails are set after each First of all trim the main very flat with the outhaul Then letadjustment to sail trim Numbering each genoa and traveler the traveler down to leeward and tighten the mainsheet Bescrew marking every inch along the outhaul and similarly careful to control the leech so that it doesnt hook to the mast for halyard tension the backstay as well Take up on the cunningham tension even to the point of creatingmakes this job much easier By using these sail trim numbers vertical folds along the luff This tension helps keep the sailyou have a sure way of repeating your trim under similar wind camber forward and makes the leech fall off to leeward whichand sea conditions will ease both the weather helm and the heeling force After a number of practice sessions you will be able to Above all have everyone including the helmsman toconstruct a complete table of the sail settings for the complete windward to keep the boat as flat as possible If you still cantrange of wind speeds This table should include the distance the keep the boat flat its time to reef the main If that wont do itsail should be off the spreader the genoa track number barber reduce the size of the headsailhaul position genoa halyard outhaul main traveler backstay Of course if you cant get either sail to trim the way you thinktension mast lean position crew weight position tacking angle it should consult your sailmaker He may be able to tell you whatand best boat speed Tabulate these trim numbers for each three you are doing wrong or he may need to rework the sail slightly totofiveknot change in apparent wind speed correct the problem For example the leech of the mainsail in When race time comes such a table can be taped to the Photo 3 was too tight The sail was considerably improved bybulkhead and used as a reference by the crew Every time the letting out two seams by after these photos were takenapparent wind speed indicator changes they should consult the 2
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