leech lines

[Wanderlust]

Can someone, or everyone, please give me a primer on the use of my leech lines. I mostly ignore them but wonder often if I should be giving them a yank or something.

[seadog6532]

I'm no expert and like you I mostly just ignore them. For the most part you trim them just like the sail. If you have cupping at the leach then ease the line until the leach luffs or trembles then pull till it stops. Mostly its just a way to fine trim the sail. I'm sure others will respond with a better method but I thought I would put in my 2 cents worth on how I do it.
Mark

[Neil Gordon]

I ignore them. I understand the mechanics of how they work but I have no idea which way makes you go faster.

[Judith]

We didn't have one until just recently, when we put in a new one. Ever since we've had Morveren (about a year and a half), the leech line had been broken, the loose end bundled-up and knotted to keep it out of the way.

Also, the leech edge of our mainsail has fluttered/luffed frequently and assertively. The first thing I did, once the new leechline was in, was play with tensioning it. Voilá! I could control the luffing. It really helps the shape of the edge, which I have to believe improves the sail's efficiency. And probably helps avoid much of the beating that results in fraying (we HAVE noticed some fraying on that edge).

This is basically what Mark is talking about, I'd say. Our experience was just a very dramatic demonstration for us that the leech line serves a very real purpose.

[Carter Brey]

Leech lines are great for reducing flogging as the wind strengthens, and I play mine constantly, but they can be too much of a good thing. Cupping of the sail leech stalls the air flow and creates vortices that reduce lift and power.

Before resorting to the leech line, it's a good thing to lower the traveler (on the main) and experiment with genoa car position. And once the leech line has been tensioned, don't forget to ease it in lighter air.

Cheers,
Carter

[Wanderlust]

Im still a little confused. Are you all saying...
That its purpose is to tension the leech anytime there is any fluttering? Is this irrespective of whether Im in light wind or heavy? I think I also read from you all that if used too much it creates a cupped main, which would be bad in heavier air but good in light air? (that I think I do get) Does that mean dont use it in heavy air of use it just a little or does this fluttering usually occur mostly in light air?
Assume I know nothing (which seems to be true) about this issue and kind of take it step by step for me. Thanks.

[D Rush]

The main purpose of the leechline is to stop the leech from fluttering. Fluttering can occur due to windspeed or when a sail is out of shape due to age.
I would think you could also control the flutter by changing halyard tension or downward tension of the leech via the sheet angle. The leechline is not a shape control. Leechlines are not very sturdy and can break if over tighten.

For the older sail or a sail that has seen tough times, the leech may have stretched making it looser, causing fluttering.
If the leech line is over tightened, the leech may become badly cupped or hooked, which will affect boat speed in a negative way by corrupting the airfoil shape of the sail.

I've known very competive PHRF racers who bought new sails when they believe the leech or the other edges of their sails have stretch or loosened.

[John Vigor]

The purpose of the leech line is more to calm the anxiety of the helmsman than to make the boat go faster.

Let me quote from an expert, Jeremy Howard-Williams, who wrote a book called "Sails" (John de Graff, New York):

"The correct use of leech lines is so rare that they should be abolished. They are a tacit confession of failure by the sailmaker, for their role is to steady a drumming leech, which should be corrected permanently in the sail loft.

"The right way to use one is to pull gently on it until the vibration partly settles down, and then to make it fast. If the line is pulled until the drumming stops completely, it will almost certainly cause the leech to curl to windward. This is the worst possible leech shape, and there are enough troubles with sails without producing any more deliberately.

"It is far better to have a slight vibration and a free run-off for the wind, than a quiet leech which is hooked. The best job the leech line does is not to the efficiency of the sail, which is not seriously impaired by so-called 'motorboating,' but to the morale of the helmsman."

Cheers,

John Vigor

[Wanderlust]

Thank you all. Seems like Ive been doing the right thing all along by basically ignoring them.

[Carter Brey]

The purpose of the leech line is more to calm the anxiety of the helmsman than to make the boat go faster.

"...the corollary being the apron string, which increases exponentially the anxiety of the captain. The apron string, used judicially, has been known to make heavy displacement vessels return to port and captains of long experience hang up their oilskins for good."

--Barnacle Bob's Big Fat Sailing Almanac and Periodic Table of the Elements, 67th edition

[John Vigor]

As a man who has earned a world-wide reputation for his expertise in playing with strings, Carter’s opinion is to be highly respected.

He’s right about the apron string. It’s connected directly to the heart string, thence to the wedding ring.

Not every boat has an apron string, but where an apron string exists it should be tugged very gently in the hope that it will guide the heart string and wedding ring to the boat, where connubial bliss will reign.

Those who pull the apron string too abruptly will find it snaps very easily, with loud and expensive noises of recrimination, leaving the puller with no strings attached. All too often, these people are known as singlehanders. So forget about your leech lines. Tend your apron strings. They’re far more important for sailing harmony.

Cheers,

JOhn Vigor

[ronkberg]

I think of a shore bound mate who can either make a TWANG for our return from a sail or use a mellow movement of the strings like Carter can produce from his instrument. We will respond positively from one and head for the horizon from the raspy sound of the other . I hope all shore bound mates can make the differentiation

Ron

[seadog6532]

I guess this explains why I sail alone...