View Full Version : Telltales on a Lug Sail
10-11-2002, 04:22 PM
I was wondering about adding telltales to my balanced lug sail. Has anyone tried this and how well did it work?? Did they try leach and or luff telltales and where were they placed??? Any comments on sailing with a lugsailas opposed to a standard rig ??
10-11-2002, 06:14 PM
I usually just stick two or three spaced-out along the leech at quarters or thirds. The uppermost one is usually the most important as it will hide behind the leech when the sail is over-trimmed. Easing until it cames back out will usually improve performance of the sail. Luff telltales on a lug can get kind of strange since the mast interferes with the airflow on one side and you may never get what would seem to be a normal reading off of them. If there is a big, upper-mid-sail area far enough aft of the mast, I'll sometimes stick one there, but the leech telltales seem to be the most useful.
I just tie a stopper knot in a piece of yarn, thread it's other end on a big needle, punch through the leech hem, pull through to the knot, remove the needle and tie another knot up against the sail with the tail trailing off the leech. Yarn telltales sometimes tend to stick on the stitching at panel seams, so it's wise to avoid putting the telltales where they can spin around and reach a seam.
10-16-2002, 12:20 PM
Thanks for the reply. I tried the luff telltales a bit last yeat and just couldn't get them to fly right. I was thinking the same thing that a set of leech telltales may be the best.
I am also wondering about my boom, it flexes a lot. I still have pretty good sail shape but am wondering if a stiffer boom would improve sail performance much. Any thoughts ?
My mast is also quite flexible and at times I am concerned it may break so I am trying to figure out how to either support it with a forestay - which is dificult due to the leading edge of the sail infront of the mast interferring when running - or by trying to stiffen the mast somehow. Any thoughts ??
10-16-2002, 05:20 PM
Flexible spars are pretty much a way of life on small boats. Sometimes boom flex can be limited by trying to move the mainsheet blocks out to either end of the boom and avoiding pulling down on it's middle where sheet tension just causes more bend. If the sailshape is still decent, rigged as it is now, it may not be a big problem. If it is causing shape problems, it's usually the bending boom eating up the draft allowance and/or foot curve in the sail and making the bottom third or so of the sail too flat to provide much power.
Mast bend can be good and it can be bad. The Chinese built huge lug rigs with unstayed masts which were free to flex as needed to soften the impact of big puffs, like a pine tree bending in the wind. On the other hand, lugsails work best with high amounts of luff tension and a flexing mast can make it somewhat inconsistent, changing the draft, sailshape and the integrity of the sail's leading edge as you hit changes in wind pressure. Obviously, a mast that breaks in a big puff would also present something of a problem.
Since that boat has such small spars, it might be easier to build another, stiffer set for heavier winds than to try adding material to modify the existing ones. I suppose you could wrap them with carbon or fiberglass or something to gain stiffness, but I don't have any experience doing it and couldn't give any specifics. Somebody here probably can. I agree that a forestay might be a real pain to deal with on that boat.
[ 10-17-2002, 12:48 AM: Message edited by: Todd Bradshaw ]
10-16-2002, 05:57 PM
It is hard to have the mast of a lug too stiff if you are trying to control sail shape with luff tension. On my rig on Dias's Harrier design we have a low stretch halyard and an efficient 4 part down haul. The carbon mast is twice as stiff as the hollow wooden mast that Dias designed and it is scheduled for a trip to the braiding machine this winter for another couple of layers.
I have the leech telltales that Todd uses as well as a set about a foot to 18" back from the luff that seem to be useful sailing up wind.
The easiest way to reinforce a wooden mast with glass or carbon is first to try some unidirectional running up the mast maybe 4 strips. If that is not enough think of the mast as a mandrel and wrap it with glass or carbon "tape". A rolling table is sometimes used for this.
The interesting challenge for hollow wooden spar builders is to copy the old canoe masts which were 5 layers of 1/32" veneer. Each layer was angled about 10 -15 degrees off center so wide veneers were not needed. Hide glues held it all together.
10-16-2002, 09:07 PM
10-17-2002, 06:51 PM
That is an interesting idea to try the unidirectional glass and then if that doesn't work to wrap it----I'm sure that would significantly stiffen the mast.
What is carbon tape ?? Is it expensive and how is it used ??
10-17-2002, 11:34 PM
Carbon "tape" is similar to glass tape, woven with finished edges. It is more expensive than glass. There are some specialty suppliers of stuff like this in relatively small quantities if you hunt around. West used to sell carbon tow a reel of carbon fibers all running in same direction. Handy for reinforcing bits but hard to handle. I had good result using it to stiffen a thwart that had a pretty long span.
10-17-2002, 11:57 PM
I fly a long (6 feet) pennant from the top end of the leech - just like the ones that designers put on their drawings. At first when people asked me what it was for I used to say it was to make the boat pretty; since then I've realized Duh! that it's a huge telltale, and it works! Now I tell people that it makes the boat go faster, but they probably still think I put it there to make the boat look pretty.
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