Standing lug question

[almeyer]

Just raised the sail this afternoon on my Penobscot 14, and I've got a crease in the sail running roughly from the clew to the head. From a thread several months ago, I gather this means I haven't got enough tension in the luff. Rather than a downhaul at the boom jaws, Arch Davis shows a collar round the mast to keep the boom from walking up. I adjusted the halyard on the yard so now the boom fits snugly against the collar, and the tension seems pretty decent, but I've still got the crease. I'd post some pics but Imagestation is down now. Any suggestions?
Thanks,
Al

[Don Bailey]

I've got the same thing in my Pooduck sail with a lot of luff tension. I wonder if it could be the cut of the sail. Been thinking about adding a grommet on the foot about 6 to 8 inches from the luff to pull that crease out since I have done that with my hand while sailing to see if the crease went away. Will be interested in the others suggestions.

Don Bailey

[almeyer]

It looks like I'm showing off my greenhorn status by using the wrong terminology. Crease runs from the clew to the throat, not clew to head. I'm learning, it just takes a little while.
Also did a search thingy and noticed a comment on another thread where Mower stated he used a downhaul on his Penobscot 14. I'm thinking a simple line from the boom jaws to a cleat on the mast. So does the collar do any good at all?

[Bob Quick]

Al
They taught me in sailing school that a boom downhaul limits the movement of the boom and therefore the point of sail. They said the recommended method of tensioning the luff of a sail was a cunningham. For a cunningham, a line is attached to the mast below the tack of the sail, led thourgh a gromment about 6 to 8 inches above the tack of the sail and back down the mast. It was then led back to the cockpit on the boat that I was on but I don't see why it couldn't be tied off at the mast.
Someone else might have a better idea.
First Try is being sanded and filled as we speak. I have the outer stem and dead wood on and plan to do the under coat this week. I still need to build the carriage for it to turn into and hope to turn Labor Day week. I'm taking a week's vacation for rendezvous, boatbuilding and the Port Townsend wooden boat show.
You're invited to the turning if you can come.
Bob

[mower]

Al:

I had the same trouble and I also played around the position of the collar that Arch Davis shows in the plans. Now I have two collars on my mast in two different positions, but to be honest, niether one works like it should for me. I resorted to a downhaul from the boom jaws to the mast partner. It works really well and makes quite a lot of difference. For the cleat, I use a simple locking cam that we use for ciching down tarps to hay stacks for export hay in Canada. If you are interested, let me know and I will take a photo and send you a genuine hay tarp cleat.

[Mike Field]

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Al, I think you'll find Bob's cunningham hole to be the best answer. (They're pretty common in modern boats that are raced, where anything you can tweak to get a smidgeon of extra performance is considered worthwhile.) It should tension the luff by taking a bit of belly out of the sail, despite hindrance from the luff edging (hem, bolt-rope) itself. But it will increase distortion in that part of the sail immediately behind the luff (ie forward of the cunningham,) it will put a fair bit of strain on the canvas, and the grommet itself will need to be well-sewn to stop tear-out.

To be honest, I really have to wonder whether it would be worth the effort.
.

[almeyer]

Did some re-reading last night, some time ago I'd copied a couple of pages from John Leather's book which discussed lug rigs. He's got a sketch which shows a fairly substantial block and tackle arrangement coming off the boom. He further states that when raising the sail, raise the halyard first to set the yard, then tension the boom with the downhaul. Not the other way around.
Bob, I understand your comment about the downhaul limiting boom movement, but I'm leaning towards giving this a try and then tweaking later. I'm having a little trouble visualizing how a cunningham works on the lug rig. It seems that instead of limiting movement at the boom jaws, you're now limiting movement at the gromment on the sail. My guess is that unlike a conventional rig (luff is fixed to the mast), the entire leading edge of the sail rotates with changes in direction. But then again I could be way off base.
Congradulations on you progress with First Try. I'd love to come help turn it over, but the drive is a bit far.
Mower, it's reassuring to hear that someone else had the same problem. My collar is epoxied on, but I'm thinking about removing it. It should probably be replaced anyway with a leather sleeve to protect the mast from the boom jaws. I made some blocks to handle my mainsheet, and was smart enough to make a couple of spares. I'm thinking about seizing a block to the boom near the jaws, and running a line fixed at the mast, through the block, and down to a cleat on the mast. If that doesn't provide enough tension, I've probably got a more serious problem.
Al

Mike, your message was posted while I was typing this one. I'm showing off my greenhorn status again, does someone have a sketch of a cunningham? Another option to muddle over.

[ 08-23-2004, 09:06 AM: Message edited by: almeyer ]

[Don Maurer]

I can't speak for a standing lug sail, but on a balanced lug, a downhaul from the boom to the step takes care of that problem nicely. I am using a 3:1 downhaul, on a 64 sq ft sail, which is overkill. A 2:1 or even 1:1 would probably work as well.

[Tonyr]

Agreed, Don. I have an 84 sq ft. balance lug, and a single part downhaul works fine. I don't know how one would sail without it.

I used to sail with the boom held with lines only, but found that too complicated. I have now rigged up a set of offset jaws about one foot from the tack, that lie along side the boom instead. I find that the whole setup works much better that way.
The downhaul is secured about 18 inches aft of that, and so acts as a kicking strap (= vang) when running (to stop the boom lifting).

Tony.

[Don Maurer]

Here's my setup. Almost a standing lug, without the jaws.

http://www.imagestation.com/picture/sraid134/p7a771d6d851a959b3b27da95a701e3e5/f7747252.jpg

[ 08-24-2004, 10:22 AM: Message edited by: Don Maurer ]

[Mike Field]

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Al, there's a diagram with some accompanying text about two-thirds down this page (http://www.cal-sailing.org/library/bluebook/dinghy6.html).
.

[mower]

Al:

If you search past posts by Todd Bradshaw, he explains another possible solution using the mainsheet, led to the forward end of the boom and achored down on the keel. This makes the mainsheet tension also tension the luff. I have not tried this method yet but it appears to be a good idea. Please remember that the issues you have with the standing lug will be slightly different from those of the balanced lug, or any other rig. I have added a photo of my crude downhaul system. It is very basic, but works like a charm. I'm sure with your superior skills, you could come up with some refinements that would make it useful for your Penobscot 14. I didn't take time to set up the rig, so you will have to use your imagination. http://www.imagestation.com/picture/sraid136/pe0a1e907973dfddb9ff88ee58fad8cdc/f74cf25d.jpg

[almeyer]

Thanks for all the suggestions. Don, that's a beautiful boat you have. Here's where I was at last Sunday when I first posted the message. Sorry about the quality of the pictures, it was hot and very muggy when I took these and the camera is accustomed to being indoors:
http://www.imagestation.com/picture/sraid136/pff528ba578249d1aa67d797b34815d77/f74e6ff7.jpg
I originally started out with a 2:1 mainsheet system, but "borrowed" somewhat Todd Bradshaw's suggestion that Mower mentioned and re-rigged it to a 1:1. A lot less line laying in the bottom. The end of the sheet is seized to a "bullseye" (right terminology?) which rides on the traveler, then to two blocks on the boom, then down to a jam cleat mounted on the aft end of the centerboard.
http://www.imagestation.com/picture/sraid136/p96574e20acf28b23b02999b38623833e/f74e6ff0.jpg
Todd's suggestion about running the sheet thru a block at the mast made a lot of sense, but I couldn't make it work for this application. I wanted to use a jam cleat rather than cam cleats - I've got cam cleats on my plastic boat and they work great, but I didn't like the look of them on this boat. I've got the theory that to be effective, the sheet (line) should be at nearly the same angle as the base of the cleat. The only way I could see to do this would be to mount the cleat on the rear thwart, which might be "inconvenient" when rowing. The best place to mount the jamb cleat was on the aft of the centerboard trunk, which meant the line sheet would be at about a 45 angle to the horizontal. For this reason, I couldn't take the sheet all the way to the mast. If I'm wrong, someone please tell me. I'm still very new at this.
http://www.imagestation.com/picture/sraid136/p38d7f307b1ad159f84d2b0bf4152bfb7/f75310cc.jpg
Last night I rigged one of my spare blocks to the boom near the mast and made a another cleat; that seemed to help a lot. Still not perfect, but a lot better, and since I'm also a beginner at sailing, I probably won't be able to tell the difference in performance if it were rigged just right.
Al

[Todd Bradshaw]

A Cunningham on a Marconi mainsail creates luff tension, but that really isn't it's function. It is designed to gather some of the sail's "belly fabric" into a wrinkle behind the mast, flattening the sail for upwind work. The wrinkle creates some turbulence, but the flatter chord shape usually makes more than enough difference in performance to make the extra turbulence worth suffering with. I can't see any advantage whatsoever to trying to add a cunningham to a lugsail as it won't be able to work the same way. Lugsail luff tension is created by the force of the unbalanced yard up top and mainsheet tension on the leech pulling up on the throat corner and against the tack corner, which should either be fixed or connected by a downhaul of some sort.

There are many things which can cause a clew to throat wrinkle to form on a lug. It's not a good idea to start modifying anything based on the boat sitting in the driveway with the sail up. You may find that the wrinkle goes away all by itself once the sail fills with wind in use. The only thing that I wonder about from the photos is the halyard tie-off point on the yard, which seems awfully far forward. I'd suggest you get the boat out on the water in medium winds and play with the rig for a couple hours to see what's actually happening before making any major changes. At this point, you just don't have enough information gathered to start re-rigging the boat.

[almeyer]

Thanks, Todd. The sail plan doesn't give the location of where to tie off the halyard, so I scaled it off the plans and started there. At that location, the boom jaws fit about three inches below the collar, so I moved the location forward until the jaws fit up against the collar, then again trying to get rid of the wrinkle. I'll move it back until the boom just rides against the collar, rig the downhaul, then wait till I get on the water and see what happens. Still need to make a cap for the centerboard trunk like Captain Pre-Capsize recommended in another thread.

Now for a really dumb question. I'm hoping to make a trip up to Austin (about 200 miles) in a couple of weeks. Is there a preferred way to fold the sail without having to unlace the yard and boom? Any place I sail I'm looking at some distance along the highway, and the sail is too nice (and too expensive) to let it just flop around in the boat. Wrapping the sail and lacing it as one big bundle might work for very short distances, but doesn't seem like a good idea for longer drives, or anything approaching highway speed. I'm thinking maybe I need to make a large "sock" that would fit the whole package.
Thanks again.
Al

[Phil Young]

You just need to move the halyard up along the head of the sail a bit. Tie it with a clove hitch and a couple of half turns, it'll stay put, until you've found the right spot. I'd say 3" or so further up will do nicely.

[Phil Young]

Oh, and take the sail off the spars and store it in a bag. You have to loosen it anyway so as not to leave it stretched all the time. If its bundled around the spars in or out of a sock/bag you are going to get chafe problems. Forget the lacing, just tie it to the ends of the boom and spar. It'll be fine.

[ 08-24-2004, 11:24 PM: Message edited by: Phil Young ]

[Todd Bradshaw]

I'll disagree with that. If you forget the lacing the yard and/or boom and their flex characteristics under sailing, halyard or mainsheet tension will be a seperate entity from the edge of the sail that was designed to be laced to, and have it's shape supported by them. It's hard enough to design and build a good sail that sets well in the first place. Having boat owners string them up in methods other than what they were designed for generally doesn't help matters at all. An unlaced head will sag and increase upper sail draft well above that which the sailmaker was trying to achieve. The same type of thing usually happens when a sail designed to be laced to the boom is run loose-footed since the feet of the two different types of sail feet are cut quite differently.

String it up the way it was intended. If not - all bets about getting good sailshape are off. For transport, I usually bring the two spars (yard and boom) together allowing the body of the sail to fold across it's middle, then roll the sail starting at the fold and ending up with a neat roll which sits on top of the spars. You can spiral-wrap the sheet or halyard along it's length if desired to help keep the bundle tight. Then it gets bagged and tied to the rack, boat or whatever. Obviously, anything that flaps violently at 60 mph. could damage the sail as could any part that slides around in transit, so do youir best to solidly package and attach the sailbag to the rack or boat. Don't leave the outhauls tensioned for months on end, but a few days isn't going to hurt anything unless you are running extremely high outhaul tensions, which would be pointless on that sail.

[Phil Young]

I would have to defer to Todd. I've sailed for some time on my 11' Oughtred Acorn Skiff without lacing to the boom and the yard. Seems to work OK, but I bet if I did lace them the sail shape would be more as designed and there might be some improvement in performance. I guess I place a premium on getting off the trailer and out sailing, and I probably sacrafice a little performance as a result.
Phil

[almeyer]

The sail plan shows the sail laced at the yard, and loose footed at the boom. Not knowing any better, I've gone with that. The halyard is attached with a topsail halyard bend, which Todd posted on another thread.
Last night I rolled the sail as Todd suggested, and it makes a much neater bundle than what I had before. For storage in the garage, that oughta do. My nearest location to sail is about 30 miles down the highway, so I'll make a cover, sock, or whatever to protect the bundle. I made some socks for my oars and they work well. (Bob Quick - these are essentially the same as the wool blanket covers we make for our flintlocks - just a little bit longer!). The sail is not super fancy (Sailrite kit), but nice and expensive enough to justify taking care of. For longer storage, and perhaps long trips, it's probably a good idea to follow Phil's advice and unlace the sail and store separately.
Thanks again for all the help.
Al

[almeyer]

Here's a pic of the downhaul I rigged. Not that complicated. The blocks may be a little big for a 5/16" line. I made them from mahog and ash scraps left over from the boat, so they didn't cost hardly anything. They're look nicer on this boat than store bought blocks (my humble opinion).
http://www.imagestation.com/picture/sraid137/p06fa732cc7501e7a293538298fa1593a/f74491e8.jpg
I moved the halyard up the yard, closer to it's orginal position. As Todd noted, I need to get out on the water before doing any final tweaking, but already the sail shape looks better than what I had before. Will try to make some caps for the centerboard trunk this weekend. Launch on Labor Day???
http://www.imagestation.com/picture/sraid137/p75aa1822f3d3a0e54cddc259cd56b450/f7448db4.jpg