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  1. #76
    Join Date
    Apr 2008
    Location
    Connecticut, USA
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    414

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    Thanks for all the info on the fixed throat.

    I'll have to do some research on how much the throat-peak tension affects my sail. My sail is cut dead flat (lay it on the floor and it doesn't wrinkle anywhere) and the head is a straight line. So changing the tension along the yard may not make as much difference to its shape as for a sail cut with some fullness.

    But I won't know until I test it. So I guess I'll fix the throat before spring and try some different tensions to see what happens.

    Thanks again!

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  3. #77
    Join Date
    Feb 2011
    Location
    San Diego, CA
    Posts
    236

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    Wow, I've missed some good stuff, but finally caught up. I also went back and read every post I could find on GIS, and other balanced lug rig tuning, in an effort to learn from what folks had already written. Yep, Callsign, I read through your entire thread for the third time - all 16 pages worth. Thanks a ton for all the info.

    I've been out four or five times since my last post, and have been testing a variety of sail tensioning arrangements. I really got buggered when I could not keep up with a teenager in a laser in light airs (granted he was a good sailer), but was happy that I could pace with a variety of larger Monconi monohulls out in the ocean in 5-10 knots of wind.

    My observations on the different tacks - sail to mast leeward or windward. No matter how I have arranged things, I don't point as high or go as fast with the sail on the leeward side of the mast. I think that it is very possible that I over-sheet on this tack. The lifting area of the sail is not only further forward from the daggerboard, but is also displaced off the mast by 4-6 inches. You can easily over-sheet and stall the sail lift relative to the board and direction of travel of the boat.

    It's like pointing while windsurfing and pushing the mast away from you. You have to push your sheet arm out the same amount or you are stalled, and going sideways. Make sense, or is it only in my imagination?

  4. #78
    Join Date
    Jul 2005
    Location
    'Delaide, Australia
    Age
    65
    Posts
    8,138

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    Howdy .. i replied to this but don't see what I wrote here.

    I wrote that being sensitive when sailing the boat is the best guide. Controlling leach tension upwind with knots in the traveller and mainsheet tension can make a big difference.

    This is of course assuming the downhaul is being used in an energetic way too.

    But just like any boat .. if you overdo pulling the twist out of the sail by these means the boat will stall.

    The main thing is that the boat is a quick one and that speed should be used to keep the foils flying.

    With the NS14 which has a lot of influence on the goat design we used to sail upwind at about 4 knots as soon as there was wind to hit this speed.

    Go faster and you get too much drag for going upwind, so it is better to maintain speed and point higher when a gust hits. We normally accompanied that with putting some extra tension in the mainsheet as soon as the boat had been gotten flat again in the new closer angle to the wind.

    When the gust ends slowly drop down to where the boat can hold your body weight out (hopefully) and ease the mainsheet a tiny amount to bring the mainsail back to its normal upwind setting.

    NS14s are so low drag that in a gust they can point maybe 5 or seven degrees higher in a little extra gust. Very nice to see fleet being sailed well and as the gusts hit they all tweak up higher into the wind.

    As you can see .. it is little bit different from the normal method on most boats of just pointing up a bit to stop the worst of the heeling. It is more aggressive and more mindful and precise.

    Where boats have not such good foils or a higher drag hullform or are stopped by waves and chop more this approach doesn't work so well.

    Best wishes
    Michael

  5. #79
    Join Date
    Feb 2011
    Location
    San Diego, CA
    Posts
    236

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    Hey Mik,
    I'm more comfortable setting the lug with a bit more wind, and I'm doing what you are describing. I've always known it as "pinching" or "popping up". Though I'm still trying to improve speed with the sail on leeward side of the mast. I'm going to try adding a kicker/boomvang and see what that does to pointing performance in more wind. This was talked about extensively in previous balanced lug posts.

    In really low wind (2-5 knots or so), I'm having trouble with the feel of the lug on the leeward side of the mast. If I think I'm over sheeted and point higher, I'm not performing. If I sheet out, I'm not performing. I've tried a few different things, and have experimented with slack versus tight outhaul, and slack versus tight downhaul, lashed foot and unlashed foot. It's a learning curve, and with very low wind, not as much data coming back at me to evaluate my changes.

  6. #80
    Join Date
    Jul 2005
    Location
    'Delaide, Australia
    Age
    65
    Posts
    8,138

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    Howdy,

    Good work! The pinching on these sorts of boats is a bit more performance oriented than blunter shapes.
    See the gust coming ... hike out hard (or as hard as you want to) before it arrives ... maybe a touch of windward heel ... as you feel the gust hit and the boat heel point up to maintain heel angle and pull in for inches of mainsheet. When gust ends allow the boat to heel to windward slightly as you bear away to balance the heel against your weight again.

    I know you probably know .. but someone will find it useful if I overemphasise the point

    The lug is difficult to feel and may die completely in super light winds less than 2 knots.

    In lightish wind it is almost a case of forgetting about where the boat is pointing and getting some speed up. The advantage of this is that the apparent wind will help the sail set better. Like you have noticed that the power is easily available in 7 knots of breeze ...

    If you are in 4 or 5 knots and start with well eased sails and get the speed before pointing up the apparent wind will be around 5 knots of wind plus maybe about half of your boatspeed ... so if you get up to 3 knots then the combined vectors will give an apparent wind of around 5 + (1/2 X 3) = 6.5 knots so getting closer to the wind velocities where the wind is strong enough to sustain easy speed.

    So never be afraid to ease sails to get your speed up.

    You probably know this as well ... but in racing it is the thing I keep having to remind myself of ... because tension/stress/wanting to do well often means I put too much tension in the mainsheet and point higher than necessary.

    Foils can be a weak spot if the boat won't go to windward well too. They are what allows you to pinch without losing speed.

    I always liked what Ben Lexcen said about what to do if you can't make the boat go well in a race.

    "if you are going slow and can't work out why, flatten the sails and ease them a bit".

    I think this works because the human tendency is to do the opposite as things get tough!

    MIK

  7. #81
    Join Date
    Feb 2011
    Location
    San Diego, CA
    Posts
    236

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    Thanks Mik, great stuff!
    I think I know what you mean. I've definitely felt the sheet hard, point high bug before, and been passed by boats that played more conservative light wind tactics, maintained boat speed, and rolled over the top of me at the upwind mark. I hate being rolled.
    Have you heard of anyone using the kicker arrangement described by keyhavenpotter in the "lug rig heaven" thread on a GIS to tighten the leach?

  8. #82
    Join Date
    Jun 2009
    Location
    New Hampshire
    Posts
    960

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    Warm Beer,

    I too, have noticed significant differences when the sail is on the leeward (good) side of the mast-- for some reason I can point higher and go faster in light winds when I'm on a port tack (bad) with the sail to windward and wrapped around the mast.

    I wonder if it's a question of the airfoil, which is for us is just working better with a shortened chord, since we both have the same sails?

    C

  9. #83
    Join Date
    Apr 2009
    Location
    Hunter Valley NSW
    Age
    69
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    1,759

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    Quote Originally Posted by callsign222 View Post
    Warm Beer,

    I too, have noticed significant differences when the sail is on the leeward (good) side of the mast-- for some reason I can point higher and go faster in light winds when I'm on a port tack (bad) with the sail to windward and wrapped around the mast.

    I wonder if it's a question of the airfoil, which is for us is just working better with a shortened chord, since we both have the same sails?

    C
    I don't really think there is any difference in pointing from one tack to the other. What skippers are perceiving, I think, is the interference of the airflow around the mast. This bubble of interference is larger when the mast is on the lee side of the sail (on the port tack), but the air soon reattaches. Skippers may compensate for this by not pointing as high.

    Have any of you measured this effect with a compass?

  10. #84
    Join Date
    Jun 2009
    Location
    New Hampshire
    Posts
    960

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    Quote Originally Posted by woodeneye View Post
    I don't really think there is any difference in pointing from one tack to the other. What skippers are perceiving, I think, is the interference of the airflow around the mast. This bubble of interference is larger when the mast is on the lee side of the sail (on the port tack), but the air soon reattaches. Skippers may compensate for this by not pointing as high.

    Have any of you measured this effect with a compass?
    I think its a boat/sail thing-- we would be hard pressed to compare my GIS to yours, with different weights and totally different sails and spar set-ups.

    I have measured it with a compass, but it's been two summers now and I'm just used to it I don't think about it anymore, so the numbers are no longer in my head and I won't just throw some digits out there that I can't back up later. I will keep it in mind for this summer though.

  11. #85
    Join Date
    Jun 2009
    Location
    New Hampshire
    Posts
    960

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    But good point, Bruce.

  12. #86
    Join Date
    Apr 2008
    Location
    Connecticut, USA
    Posts
    414

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    I have not used a compass to check how high I can point in light air. (I will do so come spring.) And I do realize that it is easy to confuse true vs. apparent wind direction when out on the water, especially when current or waves are involved.

    But I'm not entirely new to small boat sailing, so I do have some basis for comparison. And since the difference between tacks that is the exact opposite of what my gut told me to expect (i.e., I get better performance when the sail is deformed by the mast than when it is a proper airfoil shape), I don't think I have an unconscious bias. Furthermore, the difference is not subtle, at least on my boat. It is noticeable when the wind is below 8 knots or so and quite un-ignorable below 4-5 knots. I've had trouble getting through narrow passes because I'm not used to the asymmetry yet.

    I feel like I am still just scratching the surface of what I need to learn about this rig. I know from experience in other realms that I will do best if I keep a notebook next spring and methodically try a number of different things to see how to improve the boat's handling. I already have a number of experiments in mind. Some are MIK's suggestions, like limiting the play in the traveler. Others are my own ideas, like varying the amount of sail forward of the mast on the two tacks. Lots to learn. Good thing I like learning!

  13. #87
    Join Date
    Feb 2011
    Location
    San Diego, CA
    Posts
    236

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    Thanks Christophe and Paulie, I'm really glad to hear that I'm not imagining things. For me, the difference between the two tacks is quite noticeable. So much so, that if I have to work through an area going upwind, like a harbor mouth, I'll favor my port tack as much as possible (boom to windward of the mast for me is the port tack.) I can't quite figure out why this is - hence the thread. Maybe, like Wood says, it's the wind shadow of the mast. If so, is it better to let the boom move away from the mast, like Joost, better to have more sail in front of or behind the mast, like Paulie is talking about, and should you tighten the outhaul to match the same tension as when the sail wraps around the mast. I have no clue. ) Either way, it truly is like sailing with two different rigs depending on my tack. Fun learning curve.

    With the boom to leeward, I like the shape, and it looks like it's pulling efficiently. It's just not as fast. I know this sounds crazy, but what about hanging a slotted sail on a balanced lug rig, with the slot adjacent to the mast?

  14. #88
    Join Date
    Feb 2011
    Location
    San Diego, CA
    Posts
    236

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    Wood,
    I have tried to note the difference with my parrot feather, bow mounted wind indicator. It is not quite as accurate as I would like, but if I'm daydreaming I can swear I've heard it say "squawk, you're too high you idiot, squawk, you're too high you idiot".
    )

  15. #89
    Join Date
    Sep 2007
    Location
    Savannah GA USA
    Posts
    583

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    Quote Originally Posted by paulie View Post
    Thanks for all the info on the fixed throat.

    My sail is cut dead flat (lay it on the floor and it doesn't wrinkle anywhere) and the head is a straight line.
    The only sails I know of that are cut dead flat are on Chinese junks. Modernists who favor the junk rig are even putting draft in them, today.

    A flat sail is not going to give you full power and I think your sailmaker owes you a new sail.
    The "Cosmos Mariner,"My Goat Island Skiff
    http://s176.photobucket.com/albums/w168/MiddleAgesMan/

    Starting the Simmons Sea Skiff 18
    http://www.flickr.com/photos/37973275@N03/

  16. #90
    Join Date
    Mar 2010
    Location
    Queenstown New Zealand
    Posts
    382

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    Quote Originally Posted by MiddleAgesMan View Post
    The only sails I know of that are cut dead flat are on Chinese junks. Modernists who favor the junk rig are even putting draft in them, today.

    A flat sail is not going to give you full power and I think your sailmaker owes you a new sail.
    Yes, I was wondering exactly this myself, how can a sail develop proper shape if it is cut dead flat and has no edge round along the sides that are attached to spars? What is the history/origin of this sail?

    Ian

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