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Post by ianpowolny on Sept 12, 2015 17:01:30 GMT
I showed this photo to the marina manager here who races yachts.  His immediate reaction was that our main and Genoa halyard were too tight. We went out today with reduced tension on both halyards. The foot of the main now runs parallel with the boom and the Genoa has no ripples in it. Here's todays chartplotter photo close hauled:  Ian |
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Post by so36idavid on Sept 12, 2015 19:38:14 GMT
Hi Ian,
I've done a lot of racing and I know a little about trimming sails. Some of what you say in your post doesn't add up to me. Often times a picture captures sails in motion and in fact they would look quite different in real life or on video, so I wouldn't read too much into the picture. But if I had to look at that picture I would say that if anything the halyard tension is a little light. I don't like to see ripples like that in the luff. Generally you take those out by adding halyard tension. Although some boats like to have very light tension there. Certainly I wouldn't ease any further. Also there are wrinkles along the boom which is indicative of too much main outhaul.
There's no "right answer" for how much you need on any line. Sail tuning is subject to wind and wave conditions and on race boats most of these lines are tweaked regularly, if not constantly.
Finally, you say that the picture of the chart plotter was taken when you were close hauled. According to the readout your COG was 200 and the "true wind" was 76. This is broad reaching, not close hauled. But then there's "ground wind" at 287. I've never heard of ground wind, I can't imagine it was 210 degrees off of true wind so it's all a bit confusing. There's also a lot of current because your SOG and Speed are off by 1.2 kts, so that's going to complicate exactly what's going on and how the boat should be set up to deal with it.
This is all a bit technical and confusing, but at the end of the day what counts is having the most amount of fun and it sounds like you're succeeding!
David
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Post by MartyB on Sept 12, 2015 23:07:27 GMT
I would agree with halyards being too slack.....UNLESS going down wind in light conditions or upwind in lighter conditions. IE for me that would be 5-8 knots or less. Otherwise. I loosen until I see slack, then tighten so the slack is a just gone. This tension will vary depending upon wind, wave speed/size etc.
Marty
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Post by Don Reaves on Sept 13, 2015 0:13:35 GMT
According to my Raymarine MFD, ground wind is simply the actual (magnetic) compass direction of the wind. In other words, it heading + true.
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Post by ianpowolny on Sept 13, 2015 7:14:16 GMT
Interesting that you think the halyards need to be tightened as we used the electric winch to tighten the halyards. The halyards were bar tight - no chance of getting anymore tension without ripping the sail.
Also see the artical by Raymarine on True Wind v Apparent v Ground Wind and there statement
"Ground Wind is of no relevance to sailors unless we are sailing in a strong tidal current and are trying to anticipate what the wind will be like when the tide changes".
Ian
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Post by dublin on Sept 13, 2015 11:29:20 GMT
Picture suggests to me luff is not tight enough. If the halyard is tight it suggests to me the sail luff is too long. I had this problem in the past with new sails which had to be recut to allow me get appropriate tension on luff.
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Post by hoppy on Sept 13, 2015 12:02:19 GMT
Picture suggests to me luff is not tight enough. If the halyard is tight it suggests to me the sail luff is too long. I had this problem in the past with new sails which had to be recut to allow me get appropriate tension on luff. For a couple of years I thought my headsails luff could be too long until I sent my quadcopter flying around me the top of the mast where I could see that the halyard was pressed up against the halyard deflector disk. I was thinking of adding a harken deflector block to the mast to reduce the friction. Then this spring I replaced the halyard and suddenly I could tighten the luff properly. |
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Post by Don Reaves on Sept 13, 2015 12:13:14 GMT
The first time I sailed this season I made a mistake when raising my new main sail. I had the sheet and vang tensioned too high. When I raised the sail, even with the halyard as tight as possible, there were wrinkles along the luff. The problem is that I had tightened the leech rather than the luff. Once I released tension on the main sheet, I was able to raise the main another couple of inches and the wrinkles disappeared.
This doesn't explain the problem in the head sail, of course. On my ProFurl rig, the location of the tack is adjustable, so minor adjustments described by dublin can sometimes be made without recutting the sail.
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Post by MartyB on Sept 13, 2015 13:27:41 GMT
Had same issues with tightening main as mentioned. Vang, cunningham, main sheet keeping aft end of boom too low, slightly tight reef line. All of which do not allow the main luff side to tighten up. Jib....do not have a furling setup. so can not comment here. Unless it is something as mentioned at the top. Or I have one of the halyard sheaves in the mast head that is broken, making it hard to raise the halyard literally over the pin the sheave is to move on.....It is hard to get final tightness sometimes. As noted, luff of sails could be too long..... Off to pink boat race to save some ta ta's! race.pinkboatregatta.org/buy_a_buoy.cgi?buy=20150506_055203_9263&racecity=Seattleabout 0630 in my part of the world. marty |
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Post by psychotiller on Sept 13, 2015 17:31:17 GMT
Sometimes the rope in the luff of the sail can shrink and make it difficult to tighten the halyard enough to remove the wrinkles. This happened to my main and is in the loft now for repair. Not sure whether or not this is whats happening with your sail but maybe at least something to consider among the other suggestions offered.
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Post by geitz on Sept 16, 2015 17:43:52 GMT
Despite looking like the halyards are already eased, the sails look really flat in the picture. Here's a picture of mine:  |
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Post by vasko on Sept 16, 2015 18:50:00 GMT
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Post by geitz on Sept 16, 2015 19:35:34 GMT
That's a nice looking main!
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Post by jdl01 on Sept 16, 2015 22:08:06 GMT
Hello Ian,
The issue at hand is sail shape - as determined by halyard tension..I'm going to assume that we all have speed stripes to more easily recognize sail shape. As a general rule - not looking for perfection - we are looking for an evenly balanced curve - from luff to leech - across the belly of the foresail to produce an 'all round' setting for good windward performance. This even curve - balanced shape - will largely be determined by halyard tension. Irrespective of puckers in the luff, the shape of the curve is what's important. In light air you will want more draft forward - more halyard tension- to produce power at the expense of pointing ability. In a blow, you may choose to move the draft aft - less halyard tension- to reduce the pressure on the rig and allow yourself to sneak to weather with less strain/heel. In conclusion, there is no magic in a puckerless luff - the issue is the curvature of the sail behind this point. Nothing beats going out and playing with your sail settings to gain a first hand feel for what works with your boat. Log your findings and pick the best partnership settings with you boat.
Cheers -Jim
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Post by geitz on Sept 17, 2015 12:39:29 GMT
Hello Ian, The issue at hand is sail shape - as determined by halyard tension..I'm going to assume that we all have speed stripes to more easily recognize sail shape. As a general rule - not looking for perfection - we are looking for an evenly balanced curve - from luff to leech - across the belly of the foresail to produce an 'all round' setting for good windward performance. This even curve - balanced shape - will largely be determined by halyard tension. Irrespective of puckers in the luff, the shape of the curve is what's important. In light air you will want more draft forward - more halyard tension- to produce power at the expense of pointing ability. In a blow, you may choose to move the draft aft - less halyard tension- to reduce the pressure on the rig and allow yourself to sneak to weather with less strain/heel. In conclusion, there is no magic in a puckerless luff - the issue is the curvature of the sail behind this point. Nothing beats going out and playing with your sail settings to gain a first hand feel for what works with your boat. Log your findings and pick the best partnership settings with you boat. Cheers -Jim jdl01, I believe it's actually the opposite. In heavy air, flatten the sail and move the draft forward to de-power. In light air, add depth to the draft to power up, but only to a point. Either way, adding racing striped to your sails, like the stripe on Vasko's main, really help for sail trim. www.foolishsailor.com/Sail-Trim-For-Cruisers-work-in-progress/Understanding-Draft.html |
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Post by vasko on Sept 17, 2015 14:28:32 GMT
I'm EXTREMLY happy from my sails - they have been put by the previous owner and total cost according to the bill 1814 EUR for Genoa + Main - both total 63.5 sq m ( jeanneau sun liberty 34 ) the sailmaker is in Spain:  Attachment Deleted |
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Post by ianpowolny on Sept 17, 2015 17:02:09 GMT
All, I had a very interesting conversation with a Raymarine technician this afternoon when I showed him the photo of the chartplotter. Ground wind is the calculated wind direction and requires GPS for the calculation and is the actual wind. Hence where the wind is really coming. True wind at 76.3 0S is true wind direction to starboard of the centre line of the boat. Apparent is what you feel but also looks like the closed you can get to close hauled for a particular boat and sail configuration. Now let's see how emails this generates.  Ian |
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Post by Don Reaves on Sept 17, 2015 20:06:56 GMT
Ian -- That's what I attempted to say in my description of ground wind. I guess my statement that it's heading + true was incorrect, since it also accounts for current and leeway.
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Post by dublin on Sept 17, 2015 21:55:31 GMT
Ground wind as you call it or true wind in some makes of instrument is purely a mathematical calculation performed by your instruments. If any of the inputs is incorrect the result is incorrect. The old adage of "garbage in garbage out" still applies and a computer cakculation is only as good as the accuracy of the information being received from external sources.
In this case there are five main inputs
Sog and cog as provided by the gps
Speed through the water as provided by the log
Wind speed as provided by wind instrument - apparent wind speed
Wind direction as provided by wind instrument - apparent wind direction
Add to the the effect of tide and leeway
The computer uses these to calculate true wind speed and direction ( or ground as your instruments call it). It is obvious that any errors in inputs will effect the output.
From an immediate sail trim point of view true (ground) are irrelevant - they are of course relevant for passage planning, when to tack, lay lines etc. What is relevant to sail trim are the apparent sped and angle at that immediate timeas that is what the boat reaxpcts you. This is why racing crews are constantly tweeking the sail controls - to get the maximum performance from the boat.
If you have not correctly calibrated both log and wind instruments it is likely that the "true" readings provided by the MFD are incorrect. At the start of every season we carry out a full calibration of all instruments including a compass swing to minimise this effect.
The other reading on the MFD is giving wind angle as an angle relative to the boat which is a the relative bearing not effected by incorrect
In summary. For sail trim the important inputs are apparent wind speed and angle.
I'm no longer a racer, and gave not raced seriously since before the introduction of modern instrument so I'm sure the racers out there will tell me that get new instruments make the above redundant !
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Post by ianpowolny on Sept 18, 2015 6:45:41 GMT
Ground wind as you call it or true wind in some makes of instrument is purely a mathematical calculation performed by your instruments. If any of the inputs is incorrect the result is incorrect. The old adage of "garbage in garbage out" still applies and a computer cakculation is only as good as the accuracy of the information being received from external sources. In this case there are five main inputs Sog and cog as provided by the gps Speed through the water as provided by the log Wind speed as provided by wind instrument - apparent wind speed Wind direction as provided by wind instrument - apparent wind direction Add to the the effect of tide and leeway The computer uses these to calculate true wind speed and direction ( or ground as your instruments call it). It is obvious that any errors in inputs will effect the output. From an immediate sail trim point of view true (ground) are irrelevant - they are of course relevant for passage planning, when to tack, lay lines etc. What is relevant to sail trim are the apparent sped and angle at that immediate timeas that is what the boat reaxpcts you. This is why racing crews are constantly tweeking the sail controls - to get the maximum performance from the boat. If you have not correctly calibrated both log and wind instruments it is likely that the "true" readings provided by the MFD are incorrect. At the start of every season we carry out a full calibration of all instruments including a compass swing to minimise this effect. The other reading on the MFD is giving wind angle as an angle relative to the boat which is a the relative bearing not effected by incorrect In summary. For sail trim the important inputs are apparent wind speed and angle. I'm no longer a racer, and gave not raced seriously since before the introduction of modern instrument so I'm sure the racers out there will tell me that get new instruments make the above redundant ! Dublin, thank you for this very useful information. We have been trimming the boat to the wind relative to its angle and speed coming over the boat by intuition - what we knew from a little dinghy sailing. We didn't really understand what the instruments were telling us which in a way was a good thing as we have been basically sailing the boat by 'feel'. Having said that we have cover around 4000 miles in the last 4 years so we must have been getting something right. So now we'll look at the MFD in a very different light. Thanks Ian |
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Post by psychotiller on Sept 18, 2015 16:38:36 GMT
Now let's see how emails this generates. Ian LOL, truer words have never been spoken! Not sure there is a group of people on this planet with more opinions, and often different, than sailors. It does make for great reading and of course always good to get different opinions. I've not done it yet but just for fun I've often thought about throwing out a simple question just to see how many different answers I get back. Something like "Whats the best way to hold the mainsheet?" or "Whats the best way to turn the ignition key?"  |
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Post by geitz on Sept 18, 2015 16:40:28 GMT
Teeth...........toes, respectively.
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Post by psychotiller on Sept 18, 2015 17:46:17 GMT
Teeth...........toes, respectively. LOL  But what about on a downwind course? Toes on the sheet and Teeth on the key when running downwind? |
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Post by so40gtb on Sept 22, 2015 4:16:32 GMT
FWIW, I had the same experience as Don, with a new main. We always must ensure that the boom vang is released and the mainsheet has some play in it when raising the main. If such care is not taken, there's a crease near the bottom of the main and a noticeable loss of sailing efficiency occurs, as the leech has been tensioned but the luff has not, as Don notes.
Same thing, only more so, when reefing down. As the jiffy reefing line tensions up, check/release the main sheet several times while approaching the final position of the leech reef point. The idea is for the sheet to be loose enough to not pull the boom down while not so loose as to cause excessive flogging during the reefing operation. Following this approach, we've had excellent shape and efficiency on both first and second reef points this season. And marking the first and second reef points on the main halyard, using colored vinyl tape, has facilitated proper reefing greatly! Drop the halyard to the mark, tension up the appropriate jiffy line, while monitoring the boom aft elevation and mainsheet tension, and the optimal state is quickly achieved.
Look at the shape at multiple horizontal elevations of the main. It should be similar all the way up, for a loose-footed main. If not, there's probably a tension conflict going on and adjustment of the running rigging is needed.
--Karl
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But what about on a downwind course? Toes on the sheet and Teeth on the key when running downwind?