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Spacing of Luff Hardware

ted_reshetiloff

Contributing Partner
On my new main from Q I occasionaly get a chattering along the luff similar to when your leach line is too loose. Seems to be most pronounced on reaches. I was wondering if the spacing on the luff hardware was correct? Any of you sailmakers out there know what the optimum spacing is? They guy from Q came out sailing with me one day but it was blowing 25-30 and it was almost impossible to get it to make the noise. I have since been out and had it happen much more frequently, but have not had a chance to get the sailmaker back out. Cunningham/halyard tension do not seem to quiet it down.
 

stbdtack

Member III
Luff spacing

My new main has the cars about 3.5 ft apart. I get a little flutter when I'm reaching too, most often when i pull the draft fwd. It doesnt flutter enough to make any noise, but I can see it. I dont know any way to stop it without adding more cars.
Curious to hear what your Quantum guy has to say. I'll ask Billy when i get over to Doyle this week.
 

ted_reshetiloff

Contributing Partner
Mine the fluttering can get quite loud. Its like a harmonic thing where once you have the trim just so it really gets loud. Q guy initially said it was common on boats with luff hardware and that there was not much to be done about it. I have not talked with him about it since I noticed it really being loud. The day he came out we could not get it to do it much.
 

Seth

Sustaining Partner
Chatter, chatter

Well, guys-

I first saw this phemon when working for Q, and it seems to happen mostly with composite sails or those made from really stiff dacron. It is partly a function of car spacing-except that the normal rules for spacing were adhered to and it still happens-so it is very hard to predict when this will result...as weird as that sounds it is true.

There are 2 solutions. One is to increase cars (reduce spacing), but this has its' own problems- namely weight, and the increase in stacked car height when reefed or stowed.

The best solution, and one I'm sure your sailmaker will go for (since it is a one-time cure and costs less than a bunch of cars), it install a "luff line", or leech line for the luff. It may need a small purchase to get enough tension, but this is a legitimate fix-most big boat mains-especially composite sails with facny car systems (batcars, etc) have them as standard, and let's face it boys, you guys with the 38's are "right there" as big boat owners!

The smaller the boat the less this seems to happen, but not unheard of these days with fancy mast cars and composite sails.

It is elusive and not consistent-which is why the luff lne is often not fitted until you get into bigger sails-but I have seen it on Farr 395 mains, C&C 38's, Beneteau 42's etc.

Run this by your "industry professional", as let us know how it goes!

Seth
 

ted_reshetiloff

Contributing Partner
Thanks Seth. That sounds like a good solution, the luff line that is. I will mention it to the Q guy and see what he thinks. Will report back soon.
 

escapade

Inactive Member
luff flutters

Yup, Ive got'em too! New main on my E34 (Doyle pentex laminate) does the same thing in about 12 kn on a reach. Moving draft around (back) w/cunigham makes it go away (mostly). Joe (our Doyle rep on the bay) said to try fussing with halyard tension, also. Am having to learn sail trim all over again with good sails. 1/2 inch on the halyard makes a HUGE difference now! Keeps life interesting.
Have fun & sail fast
Bud E34 "Escapade":cheers:
 

Seth

Sustaining Partner
There you go...

Another party heard from..
Hey Bud,-just checking, but when you say move the draft aft with cunningham, you ARE easing it, aren't you? Adding cunnigham will pull the draft forward, not aft....But you knew that, right?:devil: :p

Seeya!
S
 

escapade

Inactive Member
Busted

Hey, I said I'm learning! :oops: Meant that tensioning the cunningham tends to calm the flutters like the luff line you mentioned would do. Hope I didn't confuse anybody besides myself. What do you expect from a foredeck monkey anyhow? Thanks for correcting me.:hail:
Have fun & sail fast
Bud E34 "Escapade":cheers:
 

Seth

Sustaining Partner
Gee, thanks!

No problemo, Bud!!

By now, you must know enough about my style that I am too "obsessive" (I had short 4 letter word in mind, but....we'll use obsessive!) to let the little ones get by-One of my goals is for this to to be the most sophisticated (in sailing knowledge, anyway) owner's group out there-hence the attention to details...

Anyway, it all makes sense-adding some cunningham should help the chatter some-just that the help comes from the added tension, not the change in draft location, and of course more cunny get the draft forward, less lets it slide back as the sail loads up. Incidentally-this points up a big advantage of composite sails; due to the resistance to stretch and distortion in these stronger fabrics, the draft moves much less as the loads increase and decrease on the sail as the wind comes up and down-meaning fewer and smaller adjustments are needed to things like cunningham, outhaul, halyard, etc....

And there you have it!
BTW- It is I who is lucky to be here!!

Cheers,
S
 

stbdtack

Member III
luff line...

Hey Seth,

How does a luff line work? A leech line will curl the leech slightly to stop fluttering when tensioned (at least that what mine has always done). So I'm curious how the luff line will affect the shape to stop the fluttering. Is this line run next to the bolt rope?
Mine hasnt really been problem enough to warrant adding a line but I havent had it out in all conditions yet.:egrin:
 

Seth

Sustaining Partner
same thing-only different

It is installed exactly the same way. Both the leech and luff have a 3-4" wide dacron tape folded over the edge of the body of the sail to cover the "raw" end of the sail and provide chafe protection (sometimes for the leech they just fold over a small amount of excess cloth, but the luff always has a folded over dacron "tape"). The leech line is sewn down inside and near the top of this fold over, and exits through a small cutout near the clew, then to a cleat of some kind.

It does not really work by curling the leech (although this will be the result-especially in older sails-in newer sails you should not have to put that much load on the leechline to stop flutter), it is simply putting some tension on the end of the sail, and this will stop the leech chatter-again-try not to put any more curl than you need to-it hurts sail shape. The idea is to ONLY put just as much tension as you need to quiet tha sail down, and not ANY more than that! Any more will cause the leech to not have a clean exit!

The luff line is done the same way: For retrofits, the luff tape will be cut open on one side, and the luff line laid down along the length of the the luff, and sewn at the top. The rest is the same as with the leech line, and you should just need enough load to stop the chatter. This should have little or no effect on sail shape for you!

OK?

Seth
 

Seth

Sustaining Partner
No need for that face

Ben,

No need for :oops: at all! I just wanted to be sure it was clear enough-for some of these things, it is hard to visualize if you have not seen them put together, so I was just trying to be overly specific-:oops: on my part!
Also, I am home with the flu and possibly not as coherent as usual (but apparently just as loquacious!). That means "wordy" for all you sailors!!;)

Keep 'em comin' though-this is all good stuff. It is a treat to be able to shine some light on these "mysteries", and see the light bulbs illuminate amongst the group!!! All questions are good questions!

Seeya 'round campus!

S
 

stbdtack

Member III
luff

Seth,
Sorry you arent feeling well....was just kidding.
Thanks for the explanation of the luff line. BTW, Bill Columbo said to say hello.
 

Seth

Sustaining Partner
Back Amongst 'em!

Thanks for the wishes! A day of rest can do wonders!

Hope you are all having a great weekend, and Ben-good to hear from Bill-send a "hello" back!

I'll be lurking!
Cheers all,
S
 
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