What are the benefits of a self tacking jib?

Technical discussion of ARC products
Kevin Keller
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Re: What are the benefits of a self tacking jib?

Post by Kevin Keller »

I think there might be some confusion after reading the latest posts here on curved self-tacking jib tracks. I think the curved track that Bill is talking about is a perfect radius curve.

I bought a curved track from Aquarius to put on my SC20 and it works great. It was recommended by Tom over the straight track for the 22. It is a compound curve and doesn't follow the radius of the foot of the sail. Even though it is curved it still uses one line. So as the car get further from the boats centerline without any adjustment of the jib sheet the sail tightens up.

It does work well for me. Right now I have it rigged for 3:1 which works pretty well but I have had it rigged for 4:1 before which worked also. From what I understand the ratio adjusts the amount of curve in the sail so that in heavier winds you would use 4:1 to give you a flatter sail.

One of the advantages to having a self-tacking jib is that if you get a gust, the jib will move out to trim itself and vice versa.
Bill Roberts
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Re: What are the benefits of a self tacking jib?

Post by Bill Roberts »

I knew this question was comlng.
A curved track is not necessarily a "curved track". The curved track that I have been talking about so far is one bent on a radius equal to the shortest distance from the center of the main beam to the forestay. A track bent on this radius, especially on an 8ft wide cat, is the one that ends up looking like a set of horns from a Texas bull. The ends are way up in the air, high, and well in front of the main beam. This track looks dangerous. It could hurt you if you fell on it. It could break your leg if you accidently stepped through the large opening between the track and the main beam and fell forward or backward.
The slightly bent track on the 22 is not a "curved track", constant radius bend. It is straight in the central area where the car runs back and forth sailing to windward, self tacking. To encourage the car to run further out toward the track ends when tacking downwind "WITHOUT SPINNAKER", the track is bent forward and up slightly toward its ends. This will encourage to car to run to the end of the track. This holds the jib flatter and further out for fast reaching, main and jib only. The bent part of a the jib track on a self tacking ARC22 has nothing to do with self tacking. It is Tom's effort to make the 22 sail faster with main and jib only and be a self tacker also. The slight bend in the 22 jib track is no detriment to sailing with spinnaker. The fiberglass trays support the curved jib track and make it impossible to step through the opening between the track and the main beam, a safety feature!
Hey Grogman, didn't know that, did you. Who ever heard of a beach cat with any safety features on it? What's going on? Is somebody a Whimp?

By the way: The New Zealand AC boat had a self tacking jib on it and the jib track was straight. No jib track hurtles on that foredeck.
Bill Roberts
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Re: What are the benefits of a self tacking jib?

Post by Bill Roberts »

Mac,
We have to understand what "curved track" means. A jib track bent to the radius of the shortest distance from main beam centerline to the forestay is what I call a bent or curved jib track. This line/radius is perpindicular to the forestay. This is a very bent track; ends are high. It is made this way for a special purpose.
The track that Tom supplies with the trays does have a slight curve in it near the ends but is straight across the center. This is not what I call a bent or curved track. For its function as a self tacking jib track, it is a straight track and it works great. As an added bonus to this track Tom has bent the ends up and forward slightly to encourage the jib cat to run further out when sailing deep downwind without spinnaker. This holds the jib further out and flatter for reaching than a straight track would do. With spin sailing downwind the jib is never trimmed out to the max. If it were, the jib would be luffing.
havliii
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Re: What are the benefits of a self tacking jib?

Post by havliii »

Let's try another angle on my question............. is there a benefit to a self tacker IF I want and need to retain the furling capability. In other words how much do I give up and how much do I gain? the question is ......... can I have both?

I know that I have to use a smaller jib sail, giving up power, but are the gains in sail management, speed through the tack, and perfect trim, enough to offset the loss of sail area.
Bill Roberts
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Re: What are the benefits of a self tacking jib?

Post by Bill Roberts »

Pro,
Read all of the comments on this thread and you will see that boat owners agree the self tacking jib makes a faster boat, more speed, higher pointing.
If you have to have a roller furling self tacking jib, it can be done. Simply buy the kit from Tom and add the kit to your present rollerfurling system and don't put the battens in the jib. Bingo, Done Deal!! Roll it up!
Now, the need for roller furling is to put the jib away when not sailing. This way when on the beach, the jib is not fluttering and flapping and in time damaging the sail.
Another way to stop a jib from fluttering and flapping when not in use is to put full battens in it. Then there is no need for roller furling to keep the sail quiet when on the beach.
See what some of the self tacking jib people who have contributed to this thread have to say about that. The full battens for a high aspect ratio jib are a "hush kit" for the jib when not in use.
Bill
havliii
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Re: What are the benefits of a self tacking jib?

Post by havliii »

Bill, I use the roller furling for two purposes, but the more important reason (at least to me) is sail plan management. Reefing the sail plan down, is quickly, and easily accomplished with the roller furler. There have been many occasions where we need to douse some sail........ FAST. This is where roller furling the jib is a really desirable feature.

The self tacker may be the best thing since sliced bread, I will explore......... but I won't give up my furling jib. The benefits of the self tacker may be less apparent when the jib sail loses (some of) that aspect ratio that you speak of. The new jib will be shorter on the foot and have the identical luff as the old one.

I suppose I could put a smaller jib sail on the boat and test, that would be an inexpensive proposition since I have many to choose from.
Bill Roberts
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Re: What are the benefits of a self tacking jib?

Post by Bill Roberts »

Take a look at Pro's picture june 13 of a rig with the low jib tack, extended jib luff with pelican stricker. This is the way you would rig your boat for a roller furling self tacker.

For any roller furling sail the included angle at the tack must be less than 90 degrees. As you described the system, that angle would be greater than 90 degrees on your boat. In this case as the sail rolls up, the foot tries to roll down past the roller furling gear and everything turns into a mess along the foot at the tack.

You must have many sudden storms where you sail. Most sailors decide what sails to use based on the wind/weather conditions before they leave the beach. Removing the jib is a good way to depower any rig.
havliii
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Re: What are the benefits of a self tacking jib?

Post by havliii »

I'm lost here, my furler connects at the junction of the bridle wires on the triangular chainplate, I don't see how any of the luff can project below onto the pelican striker and still furl.
Bill Roberts
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Re: What are the benefits of a self tacking jib?

Post by Bill Roberts »

It self tacker long jib luff rig roller furling can be done but it takes a special two legged rigid pelican stricker. We are getting into a very custom set up. Not worth it. Stay with what you have and enjoy. Simple and easy.
havliii
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Re: What are the benefits of a self tacking jib?

Post by havliii »

Well, I'm not willing to give it up that easy. A self tacking furling rig would be the 'cat's pajamas.' How about an inner forestay?
Kevin Keller
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Re: What are the benefits of a self tacking jib?

Post by Kevin Keller »

You could always put an aluminum beam between the bridal tangs and use that for the tack of your jib. That would allow you to put a roller furling jib. I've seen it on a NACRA. I guess if you bury the bows though it is extra drag. It looks a little hokey too.

I thought about doing that myself because when we sail out to our sandbar and hang out for the day I was worried about the jib still being rigged with the noise and other issues like the boat hunting back and forth while anchored. Turns out to be a non issue. The jib is quiet and just slides back and forth on the track. I also liked the ability to get rid of sail area if needed but that has never been an issue either.

The only issue with my current setup I can think of is when sailing with the jib sheet pulled in really tight it tends to pull down the leach of the jib so that below the bridal tang sometimes the luff slackens up. It helps to tighten the jib halyard a little more. The solution is to pull the mainsheet even tighter or loosen up the jib sheet a little. Not a big issue though. I am wondering if Tom or Bill has this issue also?

I think you would really like the enhancement. I don't miss the old setup at all.
Last edited by Kevin Keller on November 16th, 2014, 6:48 am, edited 1 time in total.
Bill Roberts
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Re: What are the benefits of a self tacking jib?

Post by Bill Roberts »

The only issue I can think of is when sailing with the jib sheet pulled in really tight it tends to pull down the leach of the jib so that below the bridal tang sometimes the luff slackens up.

Of course the jib sheet pulls down on the leech and head of the sail. As a matter of fact the jib sheet tension is multiplied by four pulling down on the leech to obtain the correct jib shape and position the car correctly, set the angle of attack on the jib for going to windward. There is vertical stretch in the jib sail and stretch in the halyard. After things have been loaded up sailing to windward for the first time that day, jib halyard position requires tightening. This is normal. After you have sailed the boat a few times and have adjuster the jib halyard to have a smooth luff, remember where that jib halyard position is and fix the jib halyard at that position before you go out in the future.
Bill Roberts
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Re: What are the benefits of a self tacking jib?

Post by Bill Roberts »

havliii,
The system you want could be built in a fairly neat package and it doesn't involve a forward beam or cross bar. The only draw back to the cat's pajamas is that to have these parts designed and built/made would cost a thousand dollars or more, a one off set.
Stay with what you have and enjoy the simple factory roller furling. If you want to go much faster, get a top down roller furling spinnaker rig from the factory. That is the cat's pajamas!
havliii
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Re: What are the benefits of a self tacking jib?

Post by havliii »

Thanks Bill, Thanks Kevin. I can fab in epoxy and carbon and have vacuum bag capabilities. Maybe a winter project on the self tacker? I am lusting for a triangular forward tramp as well as some other goodies, so I can see a whole winter of work ahead of me. (sorry I am getting way off this topic.)

Bill, how do I bypass the junction of the forestay and the bridle wires? The spinnaker will have to wait, it's a rare occasion that I need MORE sail area. Mostly I find myself shortening sail, even downwind I often have to douse the jib to keep the wife happy. I posted a short video of downwind speed with no jib, no spinny on here somewhere. We have returned to port on more than one occasion on 'bare poles' (and we don't carry a motor.) That's a real trip.
Bill Roberts
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Re: What are the benefits of a self tacking jib?

Post by Bill Roberts »

havliii,
Go back to the pictures in this tread. You will need a jib foot pole as shown and the roller furling drum and forestay will attach just aft of the pelican stricker tube. Now the pelican stricker tube, without spin, normally carries a small load equal to the jib luff tension, jib halyard tension, less than a hundred pounds. With the forestay load going down to the jib foot tube and then back up the pelican stricker tube, now the pelican stricker load is several hundred pounds, MANY TIMES OVER WHAT IT IS IN ITS ORIGINAL DESIGN. The pelican stricker tube must be resized, larger in diameter with thicker wall etc, much heavier. The pelican stricker must be made of two tubes one in front of the other. One tube is in the base nornal position. The second one starts about 1ft in front of the normal one on the jib foot tube and connects, is welded to, to the top of the heavy duty pelican stricker at the tri plate. This tube provides fore and aft stability. Now the pelican stricker cannot move sideways because of the bridle wires and it can't move, rotate about its base, fore and aft because of the second stability leg.
Rig the forestay and roler furling spool, jib tack, aft of the pelican stricker a few inches for clearance. As you can see this is a development program, expensive in time and money.

NOW, CARBON AND ALUMINUM DON'T LIKE EACH OTHER. THEY EAT EACH OTHER UP ESPECIALLY IN SALT WATER, CARBON TEXT BOOK 101! DON'T PUT THEM TOGETHER!

THIS JOB, PLAN, IDEA IS MUCH MORE THAN YOU PLANNED ON. PLEASE STICK WITH THE FACTORY JIB ROLLER FURLING SYSTEM AND ENJOY.

Bill
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