Leech Line

[Hadenough]

Right. I am replacing the sacrificial and edging tape to my Genoa and Staysail. Both have leech lines which I never do anything with because having set my sails from the cockpit, I really don’t want to go forward to adjust leech lines. So what is the point? Replace the (unused) leech line or not bother. Or is there a Mystic Meg system whereby I can predict the setting in advance. BTW I am talking cruising not (perish the thought) racing.

 

[TernVI]

The point of a leach line (or is it leech line?) is that you tighten it a little when the leach starts madly vibrating in a breeze. When it starts 'motorboating' it is really annoying, exagerates the feeling of being in half a gale and you will suddenly understand why a leach line is a Nice Thing To Have.
It's not really a 'racer' thing, real racers just buy new sails when the leach gets verbal.

 

[William_H]

Racing cruising all the same to my mind. You try to do it well. (sailing) As said leach line is to put tension on the leach usually pulling the leach in to a curve so leach is tighter than the nearby sail and so stops the flutter. To my mind this puts a horrible hook in the flow of air. But it does stop that flutter which is worse.
The flutter is exacerbated by mass at the trailing edge and is a very serious matter for aeroplanes. So one option is to have no hem leach cord or any thing else at the leach just a cut sealed cloth edge. Was fashionable once not sure why not now. This can be used with or without a leach that is hollow cut so leach tends to be stretched when sheet is pulled on. One last option is to fit leach battens which will definitely support the trailing edge. Not convenient if you want to furl the jib. But effective on a hank on.
So I got frustrated with one hank on jib with excessive flutter I simply attacked with scissors and cut the leach to a hollow curve shape then heat sealed the edge with a soldering iron. The cut started just below and above the reinforcing for the corner and hollowed by about 1.5 %. It was an oldish sail but is still in use with no flutter. This idea might be a challenge with sacrificial strip. ol'will

 

[RJJ]

Racing cruising all the same to my mind. You try to do it well. (sailing) As said leach line is to put tension on the leach usually pulling the leach in to a curve so leach is tighter than the nearby sail and so stops the flutter. To my mind this puts a horrible hook in the flow of air. But it does stop that flutter which is worse.
The flutter is exacerbated by mass at the trailing edge and is a very serious matter for aeroplanes. So one option is to have no hem leach cord or any thing else at the leach just a cut sealed cloth edge. Was fashionable once not sure why not now. This can be used with or without a leach that is hollow cut so leach tends to be stretched when sheet is pulled on. One last option is to fit leach battens which will definitely support the trailing edge. Not convenient if you want to furl the jib. But effective on a hank on.
So I got frustrated with one hank on jib with excessive flutter I simply attacked with scissors and cut the leach to a hollow curve shape then heat sealed the edge with a soldering iron. The cut started just below and above the reinforcing for the corner and hollowed by about 1.5 %. It was an oldish sail but is still in use with no flutter. This idea might be a challenge with sacrificial strip. ol'will

You can have softish vertical battens that go in the furler, or those natty metal strip ones that "snap" into place and snap back when you need to roll them up.

But you really don't want flutter. It's annoying. More importantly, wind tunnels showed it creates an astonishing amount of drag. More importantly, if you leave it then it's causing premature wear on the sails.

I'd go for battens and a leech line, even if you never use the latter it's hardly expensive and gives you the option.

 

[garymalmgren]

Back to the original question, So what is the point?
I am with you, Hadenough, I think there are pretty well pointless.

As mentioned they reduce leech flutter, but if that is a not a problem, the leech lines serve no function.

When I have my next set of sails made up ( just after I win the lottery according to the wife) I will do without the leech tensioning line.

gary

 

[beermonkey]

Back to the original question, So what is the point?
I am with you, Hadenough, I think there are pretty well pointless.

As mentioned they reduce leech flutter, but if that is a not a problem, the leech lines serve no function.

When I have my next set of sails made up ( just after I win the lottery according to the wife) I will do without the leech tensioning line.

gary

All depends on your 'style' of sailing.

Some like to tune a rig, sail plan and point of sale for maximum efficiency (accordingto ability) and other like to behave like gentlemen and only sail downhill with one had for the boat, one hand for the gin&tonic and one hand for... erm....

All according to taste! Although, those sail design fella's who put all that effort in so you can get an extra 0.5/1.0 kn - or have a more comfortable sail - sure do appreciate it when you do.

 

[Steve The Seagull]

A leechline is generally worth having unless your sail has quite a large amount of leech hollow, and even then there are other reasons to have one.
The leechline does not necessarily need to be adjusted while sailing, it can be tied off and left at a all round tension, and with the correct amount of leech hollow will just stop the flutter in higher wind speeds.
A added benefit of a leechline is also if you get a tear in the leech. With a line in if there is damage to leech it will keep the sail more together than just relying on the material and will generally mean for a smaller area of damage.

 

[dunedin]

As you are fiddling with the leech of your sails, it is quite likely that some adjustment will need to be made using the leech line to stop vibrating after the change. So I would definitely keep it.
The way to adjust a jib / genoa leech line underway is to tack onto the jib whilst keeping sheeted in, so become hove to. Then can go safely along the high side to make the adjustment, and the sail is blowing inboard so don't need to lean out to adjust.
Once done we usually simply gybe out and resume course with no need to winch the genoa sheet, but some may prefer to release the genoa and re-sheet on the new tack.