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Thread: Balanced Lug vs. Standing Lug

  1. #1
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    Default Balanced Lug vs. Standing Lug

    I understand that a balanced lug boom extendes beyond the mast and a standing lug's boom ends at the mast... but can one convert a balanced lug to standing lug by adding jaws to the foward and of the boom? or would they need to have a differnt sail?
    thanks
    Chris

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    Default Re: Balanced Lug vs. Standing Lug

    Roughly correct -- the standing lugsail doesn't require a boom, neither does the dipping if attached forward (like to the stem).

    http://en.wikipedia.org/wiki/Lugger


    My guess is that you could convert a balance to standing lug, but you'd need the additional space aft for the sail, and additional adjustment range on the top spar's angle.

    Let's see what the more experienced folks say...
    "The enemies of reason have a certain blind look."
    Doctor Jacquin to Lieutenant D'Hubert, in Ridley Scott's first major film _The Duellists_.

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    Default Re: Balanced Lug vs. Standing Lug

    If you convert a balance lug to a standing lug you will lose the self-vanging qualities of the balance lug. Also, if you get rid of the boom altogether then you will have to have cleats or fairleads or some such like on both sides of the boat to get the proper sheet leads and angles--you can't sheet to the centerline anymore like with a boomed balance lug. As you may have guessed by now, I kinda like the balance lug better myself.

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    Default Re: Balanced Lug vs. Standing Lug

    Yes, you will lose the self-vanging nature if you convert to a standing lug, but you gain more ability to let the top twist to leeward in a blow as a depowering tool and shock absorber in gusts because the sail is no longer self-vanging - so it's a trade-off. You may also lose a bit of downwind speed by losing the vang effect, but may gain slightly in performance to windward because it's easier to generate high amounts of luff tension and it's ability to flatten the sail with the standing lug configuration.

    Most boats will tolerate a bigger standing lug than they will a balanced lug because of the ability to let it twist and depower and the shock absorption that this provides. The exception would be Chinese lugs (which are essentially balanced lugs) some of which were huge. They were pretty easily reefed and the unstayed masts could bend like a pine tree in a blow and absorb shock as the mast bent.

    You can, if desired, go boomless on the standing lug, but if you are sailing off the wind much you'll most likely find the boom worth having to help hold the clew corner outboard and keep the foot's proper shape. There often is not an awful lot of difference in the cut, layout or perimeter shape of the two sails, though changing to a standing configuration will probably kick the tail of the boom up some, which may look a bit strange. Peak angle will also increase and the CE will move aft a little bit. Whether or not these things are appropriate for the boat and that particular sail's profile will just depend on that individual example.

    In most cases, the conversion would likely be possible from balanced to standing, but I'd have to have an awfully good reason to go to the trouble to do it because the actual on-the-water sailing performance probably won't change all that much. You still have the same hull, with the same sail area in about the same place and a pretty similar performance potential.

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    Default Re: Balanced Lug vs. Standing Lug

    Thanks all....
    the reason why I asked was I was thinking of adding a forsail for use in very light air I thought it would it would be good to move the boom out of the way... I do not plan on changing anything this season I am just very inquisitive.... I would also need to add a bowsprit, I am not shure if I would need to change to a stayed mast....
    Thanks
    Chris

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    Default Re: Balanced Lug vs. Standing Lug

    Regarding the self-vanging qualities...I'm not sure I follow...lets say the sheet is connected to about 2/3rds aft of the mast and you have a standing lug with jaws to connect it to the mast and the sail projects a little fwd of the mast and a balance lug with no jaws and the luff parallel to the mast as is often the case. If I sheet out the sail on either rig, why wouldn't the standing lug have some vanging quality to it when I also release the downhaul and give it a lot of slack as any sailor would do on a run...does the balanced lug luff move foward that much when off the wind (but it wouldn't if the downhaul was still tightened down, say, from a long beat to windward). Help me here... I'll need to draw my sail rig for my Maine Coast Dinghy very soon and could put some thoughts to work...

    Cheers,
    Clint
    Clinton B. Chase
    Portland, Maine

    http://tinyurl.com/myboats

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    Default Re: Balanced Lug vs. Standing Lug

    The tendency of the clew to lift is what the vang is for. On a balanced lug, the clew lifts until the foot becomes taut, then puts tension on the luff (which is good) until it can't lift anymore.

    I think it's best to have the boom downhaul led down to the deck, not sideways to the mast. It's supposed to be a downhaul, not a sideways-haul. The lift at the clew can only lift the aft end of the boom because the forward end is held down by the downhaul.

    If you attach the downhaul to the boom in a vertical line with the luff, put a small block on the deck a few inches off center (minimizes or eliminates the amount the sail contacts the mast on the bad tack), run the downhaul through it and aft to the cockpit, you can vary the tension on the luff, by pulling straight down on it, whereas with a standing lug, you have (if you want to go downwind safely) a vang that pulls the boom down at a weird angle, into the cockpit, where it's less effective and more in the way.

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    Default Re: Balanced Lug vs. Standing Lug

    Let's see if I can do this quickly without having to be here all day drawing pictures and writing text, so bear with me.....

    The word "balanced" is actually not a very good one to apply to any lugsail, because they work only because they aren't really balanced. A "balanced lug" is simply a version that has some of it's sail area behind the mast and also a fairly sizable portion (more than the other types) of it out in front of the mast (or some to port of it and some to starboard when sailing off the wind with the sail eased out).

    The imbalance needed to make any lugsail work and keep it looking like the profile drawings of your boat is initially due to the halyard being tied to the yard at a spot far enough forward on the yard to make the yard quite tail-heavy. If you were to leave the bottom of the sail or it's boom unattached and raise the sail with the halyard, the heel of the yard would be pointing skyward and the peak end of the yard would be in the bottom of the boat. The boom would also be at a somewhat similar angle, with it's forward (sail tack) end being pulled up and forward and the aft (clew) end in the bottom of the boat. In a profile view, the entire sail would be rotating - upward at the throat, downward at the peak and clew and upward and forward at the tack corner - all due to the unbalanced halyard-to-yard attachment. The only thing stopping this rotation would be the spars coming to rest against the hull.

    In order to peak up the yard properly, bringing down the yard's heel, raising it's peak end (and also leveling-out the boom in the process), we need something that pulls against the imbalance. We do this with a downhaul at or near the tack corner. We hold the tack corner down, which pulls down all along the sail's luff, keeps the throat corner and yard's heel from being able to rise and peaks the yard up to it's designed angle. This force is also transmitted along the sail's leech, lifting the boom's tail up off the seats and into sailing position. Our halyard tie-off position originally created a rotational force on our sailplan profile, causing the sail to droop into the boat, and now we have countered it with the downhaul, creating an opposite rotational force, bringing our sail into the proper profile attitude - and creating a goodly amount of that all-important tension along the luff and leech in the process.

    All lugsails (standing, balanced, split, dipping, Chinese etc.) need these two rotational forces pulling against each other at all times when sailing in order to keep the yard peaked up, the boom's tail out of the cockpit and proper tension along the luff and leech (since these edges are flying out in space, rather than attached to spars, the tension is all we have to keep them from being soft and flapping). If you ease the downhaul while sailing downwind, as you might on a Marconi rig, about all it will do is lower the peak and drop the tail of the boom in your lap. Even on a small sail, like a 45 sq. ft. lug, they are surprisingly strong forces if things are set up properly and you notice it as soon as you start pulling the sail up with the halyard and feel how much the unbalanced yard is pulling back against you as you do. You will then need a similarly strong downhaul force to counter it and stabilize the sail in it's proper position. When we add mainsheet tension, pulling down on the aft end of the boom, the down-force on the yard's peak and up-force on it's heel get even greater and the downhaul will need to be strong enough to also counter this increase.

    As a side-note, the easiest way to screw up this whole process is to tie your halyard too far aft on the yard. If the yard is not sufficiently tail-heavy, you'll notice that the sail goes up easier and you need far less tack downhaul tension to peak the yard up, but you will have much less luff and leech tension (more floppy) and the sail won't be stable in profile. As you sail through soft spots in the wind, make sheet tension changes, tack or make other maneuvers, the yard will tend to hobby-horse, up and down in front and back. As it does so, your luff and leech tension will be constantly changing and the boom is also likely to be bouncing around. The entire sail will be in a constant state of shape-change, rather than providing a good airfoil and power source.

    Vang - The function of a vang is to reduce upper-sail twist to leeward when the sail is in a position (usually outboard) where the boom and mainsheet aren't efficiently able to do it themselves. It pulls down on the boom, leveling and lowering it's tail end without pulling the boom inboard. This generates tension up the sail's leech, tightening the leech, trimming the peak end of the yard inboard and all this essentially trims-in the upper sail area, making it start catching more wind and working to power the boat. If you have a 20' tall sail - you might as well have all of it working for you when sailing downwind, rather than have the top third twisted to leeward and spilling wind power - right?

    Yes and no. Yes, when conditions are good you want the entire sail working and this would mean that you only want just a few degrees of twist up there (the aparent wind shifts slightly to leeward as you gain height above the water so you do want a bit of twist). Lucky for us, it's almost impossible to build a sail that doesn't twist at least a little bit, so we're good on that one. On the other hand, being able to generate rather large amounts of upper-sail twist on demand is a wonderful depowering tool in conditions where it's really blowing and you need more boat control and less power. It's kind of like being able to reef the top of the sail. The induced twist lets the top weathervane more, spilling wind and reducing the amount of power and heeling force being transmitted to the hull. A twisted, or twistable top also acts as a shock absorber when big gusts hit. This is one advantage to those new high-tech square-topped mainsails that you see on catamarans and racing boats. They add more sail area up high when things are good, but the fact that they twist fairly easily up that high reduces the shock that the extra sail area might cause in a big gust.

    Back to lugs.... A standing lug's tack corner is held at or close to the mast by it's downhaul, which can be anything from a simple line tied to the boom jaws, deck, or lower mast on small sails to a multi-part tackle for big sails which is anchored in the same general vicinity. As long as the downhaul holds, the tack corner really ain't going anywhere. On a balanced lug, the boom's heel end and sail's tack corner are out in space well forward of the mast. The downhaul needs to do two things: pull and keep the tack and heel assembly down (to generate proper luff tension) and also to keep the rotational forces of the rig (halyard tie-off imbalance, mainsheet tension, etc.) from forcing the boom forward. So our downhaul needs to be providing tension in two directions at once, pulling the forward end of the boom down and aft and holding it in this position, yet still allow the sail and boom to pivot on the mast when easing the sail out or trimming it in. More below....

  9. #9
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    Default Re: Balanced Lug vs. Standing Lug

    Didn't I say this was going to be quick? I must have been dreaming.....

    The bottom anchor point for this downhaul can be on the lower mast, mast partners area or even slightly in front of the mast. The upper end can be a lashing to the boom a bit forward of the mast/boom intersection, or in some cases people even attach it all the way forward, at the heel end of the boom. The line itself then usually stretches from it's lower anchor point upward and forward to it's boom attachment point to do dual duty, pulling the boom both down and aft. There may also be a parrel, tied to the boom and surrounding the mast at the boom/mast intersection to keep the boom from blowing away from the mast on one tack or when raising or lowering sail. One good option that seems to be highly under-used is a single, side-mounted jaw on the boom at the intersection which bears against the aft side of the mast and prevents the boom from being able to be forced forward or from wandering away from the mast on one tack. This also simplifies the work of the downhaul to only needing to provide the downward pull portion of the equation.

    In any case, these balanced lug configurations tend to fix the boom itself fairly firmly in a relatively horizontal position. It can swing outboard just fine, but it's tail doesn't lift much, even if the mainsheet isn't doing much to help hold the boom down. Keeping the boom's tail down tensions the sail's leech and this in turn tends to pull the peak end of the yard and the upper sail area inboard -- like a vang would! This is the self-vanging nature of the balanced lug configuration. Is it completely self-vanging? No, depending on the rigging you can still get some twist, but it's generally greatly reduced compared to other sail types where the boom stops at the mast (including standing lugs). Because of this limited twist, they say that a balanced lug "swings like a barn door" (however, I don't believe they've taken into account that we are no longer an agrarian society and most of us have no clue how barn doors work).

    On a small boat, the self-vanging may be the balanced lug's biggest attribute. It spreads a goodly amount of sail area with simple spars and simple controls and keeps the entire sail working nearly all of the time with no added gizmos or effort. On bigger boats with bigger sails, the same feature is probably the balanced lug's biggest problem. It doesn't allow the same amount of depowering ability and built-in safety/power control/heel control as some of it's cousins, like the standing lugsail. This is why big balanced lugs are, and always have been, pretty rare (the Chinese with their unstayed, bendy masts being the biggest exception). It's also the reason that balanced lugs (including the Chinese versions) were often fitted with very complex reefing systems to be able to reef quickly when needed.

    Anyway, that's probably more than you ever wanted to know about the standing vs. balanced lug rivalry, but hopefully it will help. Everything we do seems to be some sort of compromise. This one is no exception and has no clear-cut favorite.

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    Default Re: Balanced Lug vs. Standing Lug

    Great stuff, very clear so even folks like me with little lugsail experience can begin to grasp the basics.

    You should write a book...oh...did that already, eh?

    ;0 )
    "The enemies of reason have a certain blind look."
    Doctor Jacquin to Lieutenant D'Hubert, in Ridley Scott's first major film _The Duellists_.

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    Default Re: Balanced Lug vs. Standing Lug

    Here in the UK, at the western end of the Solent we race balanced lug sail dinghies. For single handed we use them as balanced lug rigs with no jib. When racing two up, a jib is used. Your point about the jib not catching the boom end is valid. What we do is to use a short piece of rope at the end of the boom which goes round the boom, around the mast and back around the boom. That is a loop which goes around the boom, both bits around the mast then looped again round the boom.

    http://www.johnclaridgeboats.com/lrs...ionals2006.htm

    This strop keeps the boom end throttled to the mast and out of the way of the jib and it's sheets. Sounds compicated in words but is just a small loop of rope. Look through the pics of the 2006 Nationals for a boat with a jib set. This short strop meets the nees of standing lug with jib and balanced lug on its own. Brian

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    Default Re: Balanced Lug vs. Standing Lug

    Just an additional point about position of the downhaul. When sailing as a balanced lug the downhaul is located about 12" back from the front of the boom. When using a jib and the boom strop the downhaul is re-position and fixed at the front of the boom.

    These small lug dinghies have very developed rigs and are now using 6:1 downhaul and 4:1 kickers to attain the very best upwind performance. My boat has 100% Harken blocks and even carbon spars! That's racing for you. Brian.

    Brian

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    Default Re: Balanced Lug vs. Standing Lug



    In the example above the builder says it is a standing lug but it seems to match the description of the lug with a jaw on one side beautifully described by Todd...thanks Todd! So it this a SL or a BL? How would you change this rig to be one or the other? Where would the best position be for the downhaul on a larger sail...one that is 125+ SF?

    I have been drawing my lugsail like this one by Paul Gartside....they are beautifully proportioned don't you think?

    TX

    Clint
    Clinton B. Chase
    Portland, Maine

    http://tinyurl.com/myboats

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    Default Re: Balanced Lug vs. Standing Lug

    This one is a balanced lug. Criteria: the luff is out in front on the mast all the way from tack to throat and roughly parallel to the mast and the boom crosses the mast, rather than dead-ending at it (though there have been some standing lug boom attachments that sort of do the same thing with a slight overlap forward). There is a lot of variation in the amount that different balanced lugs overlap the mast and just how much of their sail area they carry out front. Off the wind, there would be an equal difference in how much was to port of the mast and how much to starboard - or essentially just how "balanced" they really are. I have no idea if anybody has ever done any kind of serious testing to see if different amounts of overlap work better than others as long as the halyard ties on at the proper spot on the yard. It seems to be more a matter of the designer getting the sail area, CE position, general profile and peak angle to his liking taking priority over the amount of overlap. Like the Gartside drawing, Iain Oughtred's boats also often rake the mast a bit aft at the top when rigged with balanced lugs. It's a nice look, but more importantly, as the barn door swings open the raked mast makes it pivot a bit differently from a plumb mast and causes the boom's aft end and the bottom of the sail to raise a little bit as the boom is eased out. When the boat is heeling, this can allow more clearance between the boom and the water.

    If this sail was a standing lug, the chunk of sail area ahead of the mast would be a triangle in shape with the luff running from the heel of the yard down to a position at or very close to the mast, rather than being a strip running parallel to the mast as seen here. The standing lug could also be run with or without a boom. The balanced lug can not - though you could probably ditch the boom and tie the tack corner down to the rail or something, turning it into a dipping lug. As you can imagine, just about every possible combo/hybrid using elements of these basic lug types has probably been tried by someone, somewhere at some time.

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    Default Re: Balanced Lug vs. Standing Lug

    Of course you have the Nigel Irens inspired standing lug that I worked out with Tony Dias on Harrier. Mast also raked. Full battens all the way, very high peak and the yard in a sleeve. Cut high on the clew so that the foot does some self vanging. What is critical is the flex of the bottom batten, enough so that its not too stiff up wind and stiff enough to hold the foot out some off the wind. No stretch halyard and a 4 x 1 downhaul. One of the lessons learned is that you don't want mast bend in a lug rig. When it gets windy the sail gets fuller rather than flatter. I recall that some of the big Scottish luggers had mast head halyard hook type devices so that you did not get halyard compression bend.
    Ben Fuller
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    Default Re: Balanced Lug vs. Standing Lug



    I recently discovered Nigel Iren's designs...I thought of Ben's Harrier immediately.

    These rigs are as stunning as the hull, they perhaps make the whole boat stunning.

    In the process of designing my rig for my Maine Coast Dinghy....

    A big Q is why the boom/not the boom. Ed Burnett, a Nigel collaborator, decided to add the boom. Nigel's rigs have no boom. Either way, they are pretty high aspect...so I imagine they are quite weatherly rigs esp. with the firm downhaul tension. Would the boom make performance better or not as good? Ed says that the boom helps with off-the-wind sailing, getting the vanging action. But on the wind or beating, could you get the tension that an outhaul on a boom would create to flatten the sail and move the draft forward? Harrier was amazing forward, so as Ben says, maybe it all depends on the batten stiffness. Another Q regards the tall rig...these masts are pretty tall in carbon fiber, could they be build equally tall doing a birdsmouth spar for example.
    Clinton B. Chase
    Portland, Maine

    http://tinyurl.com/myboats

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    Default Re: Balanced Lug vs. Standing Lug

    Again, I don't have any real experience with lugs, but check out this cartoon by Arthur Watts, boatbuilder/teacher Simon Watts' father.

    Note how the reefed lugsail seems to be sitting on the thwarts in the boat -- hard to do that with a boom and crew sitting forward. Other advantages to going boomless include sparing crew (particularly kids) that can't seem to keep their heads down at the right time...

    http://www.arthurwatts.com/the_new_s...ze/feyther.php

    "Aye, my feyther was drowned,
    and my feyther's feyther,
    and so was his feyther a'fore him."
    Last edited by Thorne; 05-01-2008 at 02:57 PM.
    "The enemies of reason have a certain blind look."
    Doctor Jacquin to Lieutenant D'Hubert, in Ridley Scott's first major film _The Duellists_.

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    Default Re: Balanced Lug vs. Standing Lug

    I just bought a small standing lug from WB for the nutshell pram (to be used as a mizzen with some other sail I have or perhaps as schooner with second lug sail if I like its behavior as a mizzen).

    Now, would it make any sense to place the tack on a transverse rod to allow me to slide the tack as far to leeward as possible to get as much of the sail as possible away from the aero-interference of the mast? I would of course have to "dip" the yard each time I tacked to get the entire sail to leeward of the mast. For frequent coming-abouts I could keep the tack of the sail just behind the mast as would be a typical standing lug arrangement, but for longer tacks the more efficient configuration might be worth it? In other words, I guess this is sort of a "dipping/standing lug hybrid". -- Wade

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    Default Re: Balanced Lug vs. Standing Lug

    Probably not. In most cases the mast interference on one tack is nowhere near as much of a speed-brake as people think it will be.

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    Default Re: Balanced Lug vs. Standing Lug

    I've noticed no difference between tacks in my sailing dinghy (standing lug). In fact, if anything she seems to do a bit better on the "bad tack", clearly there is no difference to feel.

    So, Wade, for your Nutshell do nothing different, follow the plans.
    Clinton B. Chase
    Portland, Maine

    http://tinyurl.com/myboats

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    Default Re: Balanced Lug vs. Standing Lug

    ANy thoughts on my Q's above next to the Nigel Iren's photo of Romilly, striking boats, her and Roxane. Drop dead; I aspire to draw boats as dramatic, and of course with a lug rig.

    Cheers,
    Clint
    Clinton B. Chase
    Portland, Maine

    http://tinyurl.com/myboats

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    Default Re: Balanced Lug vs. Standing Lug

    Clint,

    No boom keeps it simpler and safer. But the boom improves sail control noticeably. If it's casual sailing you're after, skip the boom. If you're of a competitive mind, then you'll probably want the boom.

    The other factor is the beam of the boat and relative position of the clew. In other words, can you get a good sheeting angle without the boom? It depends on the boat/sail combination, of course. In some cases, you really do need a boom, as in a double-ender with a sail that runs well aft.

    My current balanced lug -- on the Whisp in the avatar -- has a boom to be balanced. I swings like the proverbial barn door. But I've sailed boats without booms and the sail basically folds up downwind, and reaching you get a fair bit of twist no matter what. But like Thorne says, the boom can hurt if you forget to duck. Jibing without one is a "what, me worry" maneuver.

    As to the mast question, I'll leave that to someone else.

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