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Discussion Starter #1
On my Bristol, the main sail, instead of attaching directly to the mast track, has a loose rope which is threaded through a number of eyes in the luff. The nylon slides then attach to this rope, and are located in the mast track.

When sailing last weekend I could see that the lower 1/4 of the main luff was too loose, and pulling away from the mast by 3" or so, thus allowing the lower third of the sail to have too much shape.

I thought I had the halyard quite tight.

What's this luff arrangement called?

How should it be set up?

Strong winds are never far away in SF Bay so I would like to get the main fairly flat. I tend to set the boat up for stronger winds and go a bit slower when the wind's light, rather than for light winds and then have to rush about in a gust reshaping and/or reefing.

The sail is quite old so I'm trying to learn how to get the best shape into it.

There's no boom vang. Well, there is, but it's on the V berth. Maybe I'll install it this weekend.

Thanks in advance!
 

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You have sail-slides stitched to the luff's boltrope, and the slides go into the track on the mast. This is not at all unusual, in fact it's pretty standard. Another, less common way, is to forego the sail slides and feed the boltrope directly into the mast track. But this tends to introduce a lot of friction into the raising and lowering of the mainsail, so you tend to see it more on dinghies/daysailers, and some raceboats with plenty of crew.

It's also not unusual to have a sail luff that is a little bit longer than the hoist. If your halyard is at full hoist, then you would take the bagginess out by pulling down on the luff with the cunningham.

The cunningham is a line attached to the base of the mast, usually with a small hook at the other end. The hook gets inserted into the cunningham cringle, which is along the luff normally a foot or so above the tack cringle (but below the first reefing cringle). The cunningham tackle often has blocks to increase purchase (much like a soft vang), but not always. The idea is to pull down on the cunningham cringle, and take the bagginess out of the leading edge of the sail, especially in heavier conditions.

Definitely get that vang rigged too. It will help you to shape the sail and take some working load of the mainsheet.
 

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Discussion Starter #3
Thanks for the reply.

However, the luff rope on my main sail is not attached to the sail at all except in the sense that it is threaded through a number of points in the luff. So if you look at it, it weaves back and forth - nylon slide, back to an eye in the sail, nylon slide, and so on.

I am used to boltropes that are stitched into the luff.
 

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Oh, okay, sorry about that. Re-reading, I see what you're saying now.

Still, I've seen your arrangement before -- but usually on smaller boats with more traditional rigs like gunters.

What boat is this that you have?
 

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Discussion Starter #5
It's a Bristol 31.1, 1984. From a bit more surfing of the interweb, I think it's called a lace or lacing line. What I can't find is much on the subject of adjusting it!
 

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That arrangement of slugs and 'jackline' is to allow the reef cringle to reach the tack hook despite the slugs being stacked up in the slot. If the slugs were directly attached then there wouldn't be enough slack to pull the reef tack point down to the boom.

With adequate halyard tension the jackline pulls tight, essential pulling the slugs and sail and track together.

If the halyard is truly at full hoist the the length of the jackline needs to be shortened, so that there's no slack in it when the sail is fully hoisted. Like this:

 

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Mark, a picture or two to illustrate would be nice. Do you have this arangement on all of your slides all the way up to the head card? What you are describing is usually done on the lower slugs and it’s purpose is to allow the sail to lay flatter on the boom so the reef tack cringle will be near the boom and ram’s head. If they go all the way up than the sailmaker (or previous owner) wanted the whole sail to lay flatter aginst the boom giving you a lower profile sail cover. In any case, you do not want this line to stretch, especially out here in SF Bay. You might consider replacing with specta webbing doubled over. I think you are in Marina Village and near my boat. I will be up in the marina this weekend and would be happy to show you what I’ve done on my boat. PM me if you like.
 

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It's a Bristol 31.1, 1984. From a bit more surfing of the interweb, I think it's called a lace or lacing line. What I can't find is much on the subject of adjusting it!
I'm surprised to hear that. I'm doubtful that this was the original mainsail design for the 31.1. Is it possible this is a second hand sail not originally made for your boat? If it's original, someone would have really had to want one of these for their 31.1.

I actually have two boats with this lacing system, but they are both dinghies -- it is a nice set-up for small boats. Neither of them is fitted with a cunningham cringle nor gooseneck. Instead, both booms "float" around the mast on boom jaws. The mainsail luff is tensioned via a downhaul running parallel to the mast, from the mast base to the boom jaws, which pulls the boom down and thereby tensions the sail luff.

Is your gooseneck fitted into a moving track on the mast? If so, it may be that it needs to be lowered.

P.S. George and Faster posted while I was typing. I think they're on to it!
 

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Wow, Faster was both faster and with a graphic to boot! ...
Great minds think alike, George! (I had the graphic already from a previous thread ;) )
 

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Discussion Starter #11
I'm going off memory now, but I think the lacing line goes all the way to the head of the sail.

I'm pretty sure it's the original sail - it has the Bristol logo on it.

Faster, thanks for the graphic, that's exactly how it looks.

So thanks for the explanation George - my understanding now is that my issue is that the line is way too loose. When the sail is fully raised, there is still lots of looseness in the lacing line. I should adjust it so it is tensioned when the halyard is fully raised.

George I'll be around on the boat this weekend and will send you a pm in a moment.

The good news is that she sailed very well last weekend in this state so it can only get better!
 

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I had a sail like that only the lacing was only on the bottom half of the luff. The lacing line was always hooking on something and impeding the hoist which is really annoying when single handing. Luckily that old sail blew out during storm and I replaced it with slides mounted directly to gromets in in the sail. Never had a problem reefing as only a few slides were involved. But that was on a 22' Sailmaster.
John
 

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Don't want to rely too much on my memory, it might only go half way up the luff. Really need to take a look.
It likely only goes to just above the deepest reef... I think your fix right now is to shorten the acting length of the 'lacing' aka jackline. Make it slightly shorter than you think proper and let the halyard tension take out the last bit of slack.
 

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What you have is called a reefing jack-line so that slugs can line-up on top of one another (slug touching slug) when the sail is partly lowered as when reefing. Usually the reefing jackline only spans the distance between the tack and the first reef.

That the bottom of the main was loose at the bottom 1/4 of sail means that the jackline is too tight and needs to be eased. How to set up such a jackline: Loosen the jackline (at the bottom or 'tack end'), Raise the sail full up, then add ~1" of stretch to the halyard for every 10 ft. of luff length, THEN pull tight on the jackline and secure it (knot it, lash it OR make a new eyespice, etc.). - thats it! When the jackline is adjusted correctly, when the sail is properly raised (there will be no 'sloppiness' in the jackline) so that the slugs are firmly attached to the jackline and the jackline is firmly attached to the sail ... all 'tight'.

Also see: How to properly raise a woven dacron mainsail ... How to properly RAISE a woven dacron mainsail - SailboatOwners.com
 
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