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Old 04-12-2011
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Loose luff on main sail questions

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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Old 04-12-2011
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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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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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Old 04-12-2011
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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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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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Old 04-12-2011
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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 itís purpose is to allow the sail to lay flatter on the boom so the reef tack cringle will be near the boom and ramís 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 Iíve done on my boat. PM me if you like.
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Quote:
Originally Posted by MarkSF View Post
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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Old 04-12-2011
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Wow, Faster was both faster and with a graphic to boot! Mark, quick question, is this line 3 strand or braided?
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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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