What's this sail control

[tireman]

New to sailing. Recently purchased a Jeanneau with inmast furling mainsail and furling genoa. Have been having trouble with both sails leaches luffing on all points of sail. Have experimented with moving jib track cars, adjusting halyard tensions, adjusting mainsheets and jibsheets all to no avail. This weekend noticed a cord protruding from bottom of leach on both sails. Seems to work with a jam cleat. Gave them a tug and voila no more problem with leach. Have been reading up on sail trim but have never seen a reference to this control. Sails are factory supplied by Jeanneau. What's this contro called and how best is it used.

[JohnRPollard]

That is the leechline. You want it just tight enough to take out the fluttering along the leech. But not so tight as to cause the leech to curl in on itself. The amount of tension required varies, depending on wind strength and point of sail.

[jackdale]

I would not give the leech line a tug. Just use two fingers and just enough tension to stop the leech from fluttering.

Also, release the leech line on the mainsail before furling. This is not usually a problem on the foresail.

[Jeff_H]

One more point, furling sails when used partially furled tend to stretch out the fabric in the leech of the sail. This is especially true on furling mainsails. There is no way around that. But very often when you see a sail which has a lot of leech flutter and requires a lot of leechline tension (so that the leech of the sail is visibly hooked to windward) the sail is blown out. So while it may look like a sail, these are not a very efficient sails. You should probably start budgeting for a replacement main and jib.

Jeff

[tireman]

Thanks for advise. I have furled up mainsail without releasing and by sounds of it to much tension on this line as it is curling the leach. One more question. These are new sails (came with new boat). Is this a control which is there to remedy a sails leach as it becomes worn? Should I have to use this control to tighten the leach in a new sail or am I overlooking some other control.

[jackdale]

If the leech of the sail flutters, snug it up a touch whether or not it is new. It provides a little extra power and eliminates an annoying noise.

[Jeff_H]

JackDale said, "If the leech of the sail flutters, snug it up a touch whether or not it is new. It provides a little extra power and eliminates an annoying noise."

With all due repect to my esteemed and very knowledgable colleague, I would agree with most of what he said, such as that even a new sail needs its leechline adjusted until the flutter is removed. Assuming that the sail was cut properly, and the sheets, sheet leads, topping lift, vang, and traveller are adjusted properly, a small amount of leech line adjustment is all that should be required on a new sail.

I agree that doing so eliminates an annoying noise. Within reasonable limits, tightening the leechline enough to stop fluttering reduces turbulence and therefore reduces drag. On the other hand, tightening the leechline curls the trailing edge of the sail to windward creating more drag and increasing heel angle. Over tightening is not a good thing so you may want to experiment with easing and tightening until you get to a setting where it does not flutter but a small amount of easing will start a flutter.

Where I respectfully do not not agree with JackDale is that curling the leech will produce more power except within very limited conditions (going dead down wind).

Jeff

[jackdale]

Originally Posted by Jeff_H

[I]

Where I respectfully do not not agree with JackDale is that curling the leech will produce more power except within very limited conditions (going dead down wind).

Jeff

I did not mean to imply that curling a leech line will produce more power. A curled leech is generally too tight.

Remove the flutter and STOP.

I have seen leech lines hardened to the point that the leech is torn; that is very bad.