Curled / Hooked Jib Leech

[fallingeggs]

I've been giving this some thought and not getting anywhere. When close hauled and close reached, the leech of my jib (105%) curls or hooks in.



I have played with the trim and the jib car setting but I can't get it to go away. (In fact, my starboard side has a floating jib car set up that I copied from Dockhead, which gives me great adjustability.)

I feel like the curl / hook is bad and causing too much drag and heel.

First, is it bad like I think?

Second, if it is bad, how do I get it to go away. Is it caused by the leech being blown out or is it a trim issue I haven't yet figured out?


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[Don C L]

Got a leech line? (small line set in to the leech edge that comes out at the bottom and has a little jam cleat?) It's probably too tight. BTW looks like your jib could use just a tad more luff tension.

[StuM]

Yes, he's got a leech line, you can see the white jammer and it's a problem.

Something looks very wrong. It appears that the leechline is very tight and also doesn't go to the jammer, but runs free to the clew. There appears to be a square of light coloured tape or something fluttering around close to the jammer and something iswrapped around the leech line at the same height.

I also agree that the luff tension is too loose.

and also:
From the set of the leech and foot it looks as thought the jib car is much too far forward as well.

[Don C L]

OK maybe the end of the leech line got tangled on sheet or cringle.. and looks like maybe it is ripping out of the sleeve?

[Scaramanga F25]

The Sunbrella sun protection may be the problem if it's not the leech line.

[savoir]

Your jib will have a piece of string coming out of the sail a couple of feet above the clew. Mark the string with a pen where it comes out of the sail cloth at the leech. The general consensus so far is that the leech line is too tight. To check on that, next time you take the boat out, uncleat or untie the leech line and leave it loose. Sail to windward for a while (on either tack) and keep a watch on the leech. Chances are that it will start to flap. Go forward while sailing to windward and slowly pull it on until the flapping stops then tie or cleat it off. Problem solved.

It could also be that the sailcloth in the aft two feet of so has had it. This is very common and happens eventually to everything from the cheapest Chinese Dacron to the most expensive carbon. Keep sailing around and pulling the leech line as necessary to stop the flapping. If you find the line back at the original marked point then this tells you that the cloth has had it. Take it to a sail maker and ask for a leech seam take up which is something that every jib needs eventually. The repair is not permanent but you should get 1 - 2 more summers from that sail.

[RedHerring]

We had the same story with a jib that came with our San Juan 21. Except that one was a simple hank-on sail, no sunbrella patch or leech line. The only thing that could make it go away was a ridiculous amount of twist, which was practically never a faster trim than sailing with the correct amount of twist and a hooked leech. Racing in a 15 boats one-design fleet is how we learned that.

The hook obviously doesn't do anything good to the airflow in the slot, but we somehow managed to work our way to the middle of aforementioned fleet with it. So, you probably aren't losing that much boat speed because of it.

If I were you, I'd try to lengthen the leech line and see if it makes the hook go away without introducing leech flutter (flutter is pretty bad for jib's life expectancy). If not, I'd just live happily ever after with a hooked leech and be happy for the extra 0.2 knots of boat speed from a brand spanking new jib some time in the future.

[jackonanthem]

Assuming the sun cover is Sunbrella and your leech line is properly tensioned the problem may be the cover. Sunbrella shrinks as it ages and would then tend to curl the leech. A possible help might be to replace it with UV protected Dacron. Not sure that would last quite as long as the Sunbrella, but either will need replacing before a new sail is done anyway.

[senormechanico]

When we had a new carbon/kevlar jib made, I insisted that we NOT have a UV cover sewn on it.
To protect it from the UV, every time we're done sailing I hoist a 40 foot long zippered sock over the furled sail with a spare halyard.

[barnakiel]

RE cut.

b.

[fallingeggs]

You're right on the leech cord. I discovered the purpose of the leech cord earlier this season, only to find that it was broken a few feet above the jam cleat. So, I bent a sail tie to the broken end of the line and hitched it to the clew. Taking the sail to a local loft this winter for repairs (including the Sunbrella), so only a temporary solution.

I pulled the leech cord as tight as I did because that it would it took to make the top of the sail stop fluttering. This is also why the jib car is rather forward as I was trying to get more leech tension. At the point where the sail stop fluttering at the top few feet, I get this blasted curl. If I can't find the sweet spot between no leech curling and no fluttering, I'll ask the sailmaker if he can do a nip and tuck.

Thanks for the help!

PS - Not surprised to hear about the halyard tension. Right now the halyard is hitched to a horn cleat on the mast. Not easy to keep the tension from the winch. I am replacing the line and adding a clutch to the mast this winter, which should take care of this problem.

[savoir]

When the only way to stop flutter is to haul the leech line on too tight then surgery is the only solution.

As for the halyard . . . . . in 1983 there were no clutches on production boats and only a few jammers. That was actually a good thing because the early model jammers were not very good and tended to do what the name suggests - jam. A knife was often the only solution.

Back then the solution was to supply lots of winches on the cabin top aft of the mast. The standard Sabre allotment was 5. You are going to have to set aside one of them for jib halyard and nothing else. Tension the halyard with the winch and cleat it off behind the winch with the line still around the drum. Either a cam cleat or a horn cleat will do the job. You have a big advantage over the guys from 1983 because Dyneema didn't exist back then and Kevlar was only for rich guys. You can now use a jib halyard two sizes smaller than the boat was designed for which makes it so much easier to handle and stow.

You can use a clutch if you want but with all those winches why bother ?

[fallingeggs]

Originally Posted by savoir

When the only way to stop flutter is to haul the leech line on too tight then surgery is the only solution.

[...]

You can use a clutch if you want but with all those winches why bother ?

Thanks! A nip and tuck sounds like the path forward in the near term.

I actually replaced the four size 30 non-self tailing winches on the coachroof with two size 40 self tailers. Huge improvement in many respects, but it means I can't dedicate a winch as suggested. And to cut down the lines in the cockpit, I'm going to leave the halyards at the mast in their own clutches.


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