Recommended Posts

My jib is a one season old lightly used Elliott/Pattison tri-radial. Since my boat doesn't had fore and aft adjustable jib block cars I had the sail made with an adjustable clew plate (like a Hobie 16 jib). From day one the leech fluttered when close hauled in winds above about 12, jib sheet attached at the center position. In this video I tried more foot tension then more leech tension with no discernible difference. On this sail I didn't have time to try the top or bottom clew plate holes, that will be the next experiment. It is hard to believe that my sail could be stretched no more than it's been used. Thoughts, comments?

 

Share this post


Link to post
Share on other sites

Ah! A mystery indeed. Using  the upper holes should help ( more leech tension ). Maybe more LUFF tension? When all else fails, call the sailmaker - they are the experts. Happy Sailing!

  • Like 1

Share this post


Link to post
Share on other sites

Thanks xonk1. I do intend to try the upper clew plate hole at next opportunity in addition to tightening both my standing rigging tension and jib downhaul.

Share this post


Link to post
Share on other sites

I think that you are not sheeting the sail hard enough. The jib should be set up with a 2;1 purchase and sheeted flat.

This has not been an issue for you because you are not trapezing and depowering in the gusts.

Try getting  a crew on board and see how the sails performed when sheeted harder

  • Like 3

Share this post


Link to post
Share on other sites

Don't think rig tension will do anything.  The platform is so flexy just because it's a cat it won't matter.  What will is mainsheet tension because that will bear directly on the jib luff.

When going anything but off the wind try to keep the main sheet tight, use the traveller to let it off but that'll work on the luff.

Share this post


Link to post
Share on other sites

Things to check

not enough leech hollow?

leech battens?

cut of sail?

Tie the luff horizontally between two trees, sheet on by hand and see if the leech hooks or falls, take a pic and post (from the foot looking up the sail)

  • Like 1

Share this post


Link to post
Share on other sites

Is this a furling jib?  Did you store it furled over the winter?  If so, then the leach could have stretched (which happens on furling jibs--actually all jibs, but faster on furling jibs).  EP (and most sailmakers) normally puts a leach cord and tiny cleat in the leach that allows you to tension the leach while underway.  If there isn't one, contact EP and ask them if they'd put one in for you and show them the video.  Yah, it sorta messes up the flow off the back of the sail a tiny bit, but not as much as the flutter...

  • Like 1

Share this post


Link to post
Share on other sites

I just noticed that you said "from day 1".  In that case, EP probably didn't put enough leach hollow or misplaced it.  Contact them, they will fix, I'm sure.

Share this post


Link to post
Share on other sites
On 7/14/2018 at 11:51 AM, xonk1 said:

Maybe more LUFF tension? When all else fails, call the sailmaker - they are the experts. Happy Sailing!

I do intend to experiment with luff tension/downhaul as well, just not there yet. Already called Skip. He suggested using the camera to get footage of the leech when fluttering so he can assess the issue and that's a great idea. Problem for me is the mounting as I don't use the universal type RAM mount balls. Maybe I can borrow some of the RAM mount stuff from a friend and video the luff, it's only time !@#$!@#$!@#$

Share this post


Link to post
Share on other sites
On 7/14/2018 at 2:54 PM, teamvmg said:

This has not been an issue for you because you are not trapezing and depowering in the gusts.

Try getting  a crew on board and see how the sails performed when sheeted harder

Oak Hollow Lake is my home base and where these videos were shot. The winds are so shifty (literally instantaneous 180 deg. at times) and unpredictable in the strength of gusts that I very, very rarely use a trap on this lake as doing so most often results in a reverse capsize, pitchpole or other nasty situations.

Here is a video with crew of about 175 lbs (I think that's what he said) sheeting very hard (yes still 1:1, but very hard, jib attached center hole) and indeed I see/hear much less flutter.

 

 

Share this post


Link to post
Share on other sites
On 7/14/2018 at 7:43 PM, Rushman said:

Things to check

not enough leech hollow?

leech battens?

cut of sail?

Tie the luff horizontally between two trees, sheet on by hand and see if the leech hooks or falls, take a pic and post (from the foot looking up the sail)

Leech hollow and cut of sail, it's a virtually new EP tri-radial. If anyone would know how to make a sail for this boat correctly I would think it would be Skip as he made the originals. The sail does have leech battens, but I can check to see that they are in securely, good suggestion. I can attempt the horizontal tree test on the boat and simply shoot some pics from below, not sure when I'll get to it.

Share this post


Link to post
Share on other sites
14 hours ago, MultiThom said:

Is this a furling jib?  Did you store it furled over the winter?  If so, then the leach could have stretched (which happens on furling jibs--actually all jibs, but faster on furling jibs).  EP (and most sailmakers) normally puts a leach cord and tiny cleat in the leach that allows you to tension the leach while underway.  If there isn't one, contact EP and ask them if they'd put one in for you and show them the video.  Yah, it sorta messes up the flow off the back of the sail a tiny bit, but not as much as the flutter...

Not a furling jib and always stored very neatly rolled. This sail didn't come with a leech line, but it may be necessary if going back to a 2:1 sheeting system and playing around with other things doesn't work. I hate the 2:1 setup as it's sooooooooo much line to take up even if you use pigtails IMO.

I have shared the video with Skip E see above reply.

Share this post


Link to post
Share on other sites
On 7/14/2018 at 2:54 PM, teamvmg said:

Try getting  a crew on board and see how the sails performed when sheeted harder

Here is a video with my regular crew, about 110 lbs., jib attached at center hole, and not sheeting as hard as Curtis (previous video). Indeed I see more flutter.

 

Share this post


Link to post
Share on other sites
2 hours ago, leeboweffect said:

Leech hollow and cut of sail, it's a virtually new EP tri-radial. If anyone would know how to make a sail for this boat correctly I would think it would be Skip as he made the originals. The sail does have leech battens, but I can check to see that they are in securely, good suggestion. I can attempt the horizontal tree test on the boat and simply shoot some pics from below, not sure when I'll get to it.

Skip may know how to make the sail but does the apprentice out on the loft floor?

 

Share this post


Link to post
Share on other sites

With all due respect neither of those videos have anywhere near enough sheet tension for going upwind.  The sail will be cut to be set in a certain way, if you're not getting to those loadings and particular not in a consistent way it'll be hard for a sail maker to give you a product that will "work" consistently.  If you're dead set against adding a 2:1 jib sheet you'll either need to get the sail make to cut a big curve out of the leach or add an adjustable leach line.

Share this post


Link to post
Share on other sites

This probably has nothing to do with the flutter since that is most often caused by loose leach roach.  BUT, in the videos, the sheeting angle appears to be pulling more toward the top of the sail instead of just above the middle.  Lowering the tack would help that, but would also probably make the flutter worse unless the flutter is coming from between two battens that would twist off if the sail was set lower. 

Is the sail fully or partially battened? 

  • Like 1

Share this post


Link to post
Share on other sites
16 hours ago, MultiThom said:

BUT, in the videos, the sheeting angle appears to be pulling more toward the top of the sail instead of just above the middle.  Lowering the tack would help that, but would also probably make the flutter worse unless the flutter is coming from between two battens that would twist off if the sail was set lower. 

Forgot I had this pic. Here is a side view of the boat, jib sheet attached at the center hole on the adjustable clew plate. The luff intersection is below 50%, my guess is right at 40%, red line, which is what most references I've checked suggest.  The foot appears cupped to me, over sheeted. Not sure what you're seeing in the video that makes you think there is excessive leech tension?

The tack is as low as it can go do to the required bridle wire length. It's attached right at the intersection plus shackle.

Thanks for your input!

JibAngleA.jpg

Share this post


Link to post
Share on other sites

Thanks, that photo is better than the video in showing the sail and the geometry.  The leach cord will fix the problem.   I'm not sure why you need those battens since the leach has a hollow, not a roach (of course, the sail would be smaller, though since the hollow should be about 7% of the leach length).  Not sure which references say to have the luff intersection at 50%...what they "should" say is split the angle created by the intersection of the leach and foot (that way you get similar leach and foot tensions);  I've always found that is a good starting point but that (depending on the cut) that I'm usually more happy with it pointing above a little when seeking power and lower down to twist off the top when shedding power.  And, you are correct, in that photo the foot looks overtensioned.

  • Like 1

Share this post


Link to post
Share on other sites

From a designer's point of view you're both right.  The traditional solution is to split the difference between those two measurements but make sure sheeting angle can be adjusted so both are possible.

Share this post


Link to post
Share on other sites
2 hours ago, MultiThom said:

Thanks, that photo is better than the video in showing the sail and the geometry.  The leach cord will fix the problem.   I'm not sure why you need those battens since the leach has a hollow, not a roach (of course, the sail would be smaller, though since the hollow should be about 7% of the leach length).  Not sure which references say to have the luff intersection at 50%...what they "should" say is split the angle created by the intersection of the leach and foot (that way you get similar leach and foot tensions);  I've always found that is a good starting point but that (depending on the cut) that I'm usually more happy with it pointing above a little when seeking power and lower down to twist off the top when shedding power.  And, you are correct, in that photo the foot looks overtensioned.

Sailmaker told me the 50% luff is always a good starting point for all aspect sails.

From the sail pictured above, splitting the leech and foot you would be at about 30% luff and would be really tight along the foot with a fluttering leech.... 

  • Like 1

Share this post


Link to post
Share on other sites
29 minutes ago, Rushman said:

Sailmaker told me the 50% luff is always a good starting point for all aspect sails.

From the sail pictured above, splitting the leech and foot you would be at about 30% luff and would be really tight along the foot with a fluttering leech.... 

Well, he's already really tight along the foot with a fluttering leach.   Since that particular sail has horizontal foot and nearly vertical leach, splitting angle gets you about 50% luff by my eye which is currently a problem for him.  If it were me, I'd hoist the jib higher since he doesn't have a jib track and see if that helps.  Alternatively, I'd barberhaul/twing to the shroud further forward and see if that helps.  But really, the best thing is to show EP the video and ask Skip to remake the sail with a leach cord and/or slightly longer foot.  Skip takes a lot of pride in his sails and really doesn't want unhappy customers.

Share this post


Link to post
Share on other sites
43 minutes ago, MultiThom said:

Well, he's already really tight along the foot with a fluttering leach.   Since that particular sail has horizontal foot and nearly vertical leach, splitting angle gets you about 50% luff by my eye which is currently a problem for him.  If it were me, I'd hoist the jib higher since he doesn't have a jib track and see if that helps.  Alternatively, I'd barberhaul/twing to the shroud further forward and see if that helps.  But really, the best thing is to show EP the video and ask Skip to remake the sail with a leach cord and/or slightly longer foot.  Skip takes a lot of pride in his sails and really doesn't want unhappy customers.

Splitting angle?  Can you explain further as I must be doing it wrong if you get 50% luff

Using the highest hole in the clew board might help too

Share this post


Link to post
Share on other sites

Well, after looking at a closeup, it is lower than the mid luff right now.  And this isn't a real tri radial, either.  More of a radial clew design.  If you look close, I would want to have the angle of the pull go along the seam just above the red line for the middle hole.  But still, talk to EP...at the very least, the sail needs a leach cord. 

  • Like 1

Share this post


Link to post
Share on other sites
1 hour ago, MultiThom said:

Well, after looking at a closeup, it is lower than the mid luff right now.  And this isn't a real tri radial, either.  More of a radial clew design.  If you look close, I would want to have the angle of the pull go along the seam just above the red line for the middle hole.  But still, talk to EP...at the very least, the sail needs a leach cord. 

You say splitting angle... Can you explain this as I am not familiar with this concept/description

It is a leech cord, unless you use a coloured line line that leaches colour into the sail

Share this post


Link to post
Share on other sites

Is the jib as low as it can go on the jib bridle, if you don't want to try the doubler on the jib sheet, You can try pointing up so there is no load on the jib and getting your crew to put their feet against the mast and pulling with all their strength on the jib sheet including their leg strength, then put it back onto the wind. If it's still fluttering, the doubler isn't the answer

Share this post


Link to post
Share on other sites
14 hours ago, MultiThom said:

Not sure which references say to have the luff intersection at 50%...what they "should" say is split the angle created by the intersection of the leach and foot (that way you get similar leach and foot tensions);  I've always found that is a good starting point but that (depending on the cut) that I'm usually more happy with it pointing above a little when seeking power and lower down to twist off the top when shedding power.

Just what I read, 40 - 50% from the tack up the luff. I have also been given these figure by several sailmakers I've worked with.

http://www.onesails.com/headsail-trim

https://www.sailmagazine.com/racing/headsail-sheeting

http://www.teamwindcraft.com/basics-of-trimming-your-headsail/

Do you have a reference for the "split the angle" theory?

Share this post


Link to post
Share on other sites
11 hours ago, Rushman said:

Sailmaker told me the 50% luff is always a good starting point for all aspect sails.

From the sail pictured above, splitting the leech and foot you would be at about 30% luff and would be really tight along the foot with a fluttering leech.... 

I have been told the same by several sailmakers. I agree that going for the "splitting the angle approach here would really over tension the foot.

Share this post


Link to post
Share on other sites
2 hours ago, madboutcats said:

Is the jib as low as it can go on the jib bridle

Yes

Share this post


Link to post
Share on other sites
1 hour ago, leeboweffect said:

Do you have a reference for the "split the angle" theory? 

No, I honestly don't read about sailing and trimming or even listen to sailmakers since I make my own sails and have been sailing/racing for 20 years.  But I do understand the physics of it.  If you pull at an angle that bisects the angle formed by the leach and the foot, you will be putting equal tension along the leach and the foot.  Think about it at the extremes-pull straight aft along the foot--leach is loose; pull straight down along the leach, foot will be loose.  Given a "need for speed", I'd want the foot loose and tight leach.  Given overpowered, I'd want the foot tight and the leach loose to shed power aloft. 

In the sails I've made that are crosscut, I've found that the optimum (sailing speed) is when the leach is tensioned more than the foot-but then, my boat then was rarely overpowered.  In the radial head sails I've made, the optimum is more middle, but I've never made a sail where the optimum is below that.  It may be true that other sailmakers design more twist into their sails than I do, I've had difficulty achieving added twist without ending up with a fluttering leach (but I always end up with a leach flutter as the sail ages, which is why I always put in a leach cord). 

  • Like 1

Share this post


Link to post
Share on other sites
8 hours ago, Rushman said:

It is a leech cord, unless you use a coloured line line that leaches colour into the sail

You guys from down under never spell things wright. :)

Share this post


Link to post
Share on other sites
16 hours ago, MultiThom said:

You guys from down under never spell things wright. :)

I sea what you did there :lol:

splitting the angle?  Can you please explain in detail as I am still confused how this works in practise

Share this post


Link to post
Share on other sites
7 hours ago, Rushman said:

I sea what you did there :lol:

splitting the angle?  Can you please explain in detail as I am still confused how this works in practise

Well, it helps if you have a jib track and a new jib you haven't dialed in.  On a calm(er) day, you raise the sail and sheet in while you are tied to the dock.  Get off the boat and look at the angle the sheet is making with the clew compared to the foot and the le(e)(a)ch.  Not all jibs have a foot parallel to the deck, nor are all le(e)(a)ches nearly vertical (high clew, low clew.  Position the jib track car so the line formed by the sheet and attaching to the clew is pointing toward the middle of an extension (in your mind's eye) of the line created by the foot and leach.  Go sailing.  Look at the shape,  move the car until the boat feels right for that wind...start there next time.  It's a touchie feelee process and presupposes you know your boat but have a new jib.  If you don't know your boat and don't have a jib track (and it is easier for you), start by what others have said...point the sheet at midluff.

Share this post


Link to post
Share on other sites
6 hours ago, MultiThom said:

Well, it helps if you have a jib track and a new jib you haven't dialed in.  On a calm(er) day, you raise the sail and sheet in while you are tied to the dock.  Get off the boat and look at the angle the sheet is making with the clew compared to the foot and the le(e)(a)ch.  Not all jibs have a foot parallel to the deck, nor are all le(e)(a)ches nearly vertical (high clew, low clew.  Position the jib track car so the line formed by the sheet and attaching to the clew is pointing toward the middle of an extension (in your mind's eye) of the line created by the foot and leach.  Go sailing.  Look at the shape,  move the car until the boat feels right for that wind...start there next time.  It's a touchie feelee process and presupposes you know your boat but have a new jib.  If you don't know your boat and don't have a jib track (and it is easier for you), start by what others have said...point the sheet at midluff.

Thanks for the explanation. Sounds simple enough, I will pack a protractor in my sailing bag next time I go sailing :huh:

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now