Self tending jib sheet?

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Self tending jib sheet?

Postby Breakin Wind » Tue Jan 08, 2013 12:15 am

While doing some digging on the Internet for information on jib sheeting, I found this interesting diagram...

1459

I've never seen anything like this, but I know I don't have a lot of nautical miles under my keel too. I know its not on a daysailer, but I'm curious, Is this for real, or an April fools joke?

Anyone ever see anything like this before?

Thanks - Scott
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Re: Self tending jib sheet?

Postby Alan » Tue Jan 08, 2013 12:53 am

http://www.harken.com/content.aspx?id=3911

Here's one. I've found a goodly number of references to them, while daydreaming my way around the internet.

I won't say I haven't thought about it, for times when I was just tootling along with non-sailor friends, but I don't see how you could make one work on a Daysailer. There isn't enough flat foredeck space to mount a track, and the jib overlaps the mast.
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Re: Self tending jib sheet?

Postby ChrisB » Tue Jan 08, 2013 9:01 am

Scott,

I've seen self tending jibs used on larger, cruising boats in a cutter rig. The self tending jib is the aftmost of two headsails with a roller furling genoa set forward of the self tending jib. The idea is to give the ability to increase or decrease headsail area quickly as weather conditions change. I've never seen one on a small boat and as Alan pointed out, they will not work with an overlapping jib.

I've never seen one like your picture where the tack of the self tending jib is fixed to the stemhead.
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Re: Self tending jib sheet?

Postby Salty Dog » Tue Jan 08, 2013 4:54 pm

I've seen a pic of one on a bigger boat with a boom and a car on a simicircle track. It was called self tacking jib.
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Re: Self tending jib sheet?

Postby GreenLake » Tue Jan 08, 2013 7:32 pm

Besides issues with overlap, self-tending jibs don't work for heaving to (at least not without modifications).
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Re: Self tending jib sheet?

Postby PassingWind » Tue Jan 08, 2013 11:01 pm

Look up the harbor 20, they sell a self tacking option. Similar to what you posted but i think the pole mounts directly into the top deck.
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Re: Self tending jib sheet?

Postby jdoorly » Wed Jan 09, 2013 2:30 am

Yes, the overlapping jib does present a problem, but not impossible, for a self tending jib sheet. It would be easiest to buy a used jib made for a smaller boat that did not overlap the mast. If it also had a low clew that would help. However, you don't have to have a jib boom, but the trade-off is the noise from the sheet rattling on deck when the jib luffs.

The newest technology for jib booms is the Hoyt Jib Boom (seen here: http://www.harbor20.org/. Gary Hoyt continues to innovate and design useful stuff for sailboats, my favorite is the Hoyt Gunmount that attaches a spinnaker pole in a sleeve with the sleeve attached to a sturdy bow pulpit. It allows a standard spinnaker to be launched and carried under complete control since both sheets go through the 2 ends of the pole. The Hoyt Jib Boom attaches thru the foredeck about 18 inches aft of the stem. The boom has bushings at foredeck level, rises about a foot high then angles back toward the mast. The geometry of the offset causes the jib to present a more curved planview (birds eye view) as the jib sheet is let out.

But, you can use a 'lapper' jib for self tending, though a bow pulpit will probably be in the way. The idea is to mount both the clew and the tack to a boom. Mount the forestay to the front of the boom (or use the halyard). Now push the sail forward so there is no overlap. At the point on the boom that is over the stem fitting attach the boom to the stem. Weird looking? Yes, but it works well and is very close winded! I just saw a pic of one of these rigs- I'll post it if I can remember where!
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Re: Self tending jib sheet?

Postby GreenLake » Wed Jan 09, 2013 4:39 am

I can help but wonder whether a self-tending jib would be "appropriate" for a DS. On a much larger boat, where one needs to operate winches, I can see where a self tending jib makes for more relaxed sailing when single handed (or short handed). On a small dinghy where everything's in reach, I'm less sure. It helps to be organized when sailing alone, with a carefully worked out sequence of actions during a tack, but in the winds that I like to go out in by myself, I don't see the point of having this "automated." (I'm also leery of cluttering up the boat with lot's of additional fittings - I like to be sure that the effort of making a change is rewarded with a very definite improvement, preferably of the kind described as "how did I ever manage to do without").

That doesn't mean I don't enjoy reading this thread and following along all the different design possibilities.
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Re: Self tending jib sheet?

Postby PassingWind » Wed Jan 09, 2013 8:03 am

Hoyt has a design that allows you to use larger genoa's on a sailboat and dont get hung up.

http://www.garryhoyt.com/id38.html

I dont see the value of a self tacking jib unless you were solo and sailing very long distances or i guess if you are old and tired
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Re: Self tending jib sheet?

Postby Breakin Wind » Wed Jan 09, 2013 12:10 pm

PassingWind wrote:Hoyt has a design that allows you to use larger genoa's on a sailboat and don't get hung up.

http://www.garryhoyt.com/id38.html

I don't see the value on them unless you were solo and sailing very long distances.


I think this is the same setup that jdoorly had referenced a couple posts up...

To me (and my very limited knowledge) this starts to look like a Lateen (spelling?) sail, which is what I had on my very first (doesn't really count) 10' styrofoam (with plastic coating) sailboat year before last.

Adding to the non-boom discussion, if implementing a soft (boomless) auto tack system, why couldn't a jib sheet traveler be curved to basically match the curve of the cuddy top. It's the end point locations that matter (I think). When tacking with standard sheets, the sail pulls the slack sheet across the front of the boom, why would it care if it was a single sheet line attached to a block on a traveler rather than a pair of sheet lines running back? The wind would still carry the jib clew across to the leeward side and just drag the block on the traveler with it?

Thanks - Scott
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Re: Self tending jib sheet?

Postby PassingWind » Wed Jan 09, 2013 1:06 pm

I think the issue is that if anything you want it curved up not down. The force on the jib sheets would cause the jib car to want too start moving to center if the track was curved down. Curved up it would stay out where its supposed to. Here is a pic where they raised the track up and it looks curved up as well. You can easily do this

Image
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Re: Self tending jib sheet?

Postby PassingWind » Wed Jan 09, 2013 2:43 pm

Harken does sell the track with ends curved down. Here is the link, look at the bottom section of where the link takes you

http://www.apsltd.com/c-1388-harkending ... pto27.aspx
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Re: Self tending jib sheet?

Postby jdoorly » Thu Jan 10, 2013 12:18 am

Yes, I was speaking of the balanced jib idea, no, I wasn't thinking about the Hoyt balanced jib (I forgot about that). I was thinking about this boat: http://www.swallowboats.com/our-boats/open-boats/storm-17 There was a pic in a 2006 issue of Water Craft (U.K.).

The feature of the balanced jib is that you don't need much muscle or winch to pull it in even on larger boats, because it's BALANCED! :D

ooops, this is a better pic of the balanced jib: http://www.swallowboats.com/bayraider-17

I think the "U" shape jib travellor is meant to hold the jib under more tension while it is going across or luffing and thereby quiet down that process. In the first post graphic notice the old style travellor's bend indeed 'would compliment the cabin line.
Last edited by jdoorly on Thu Jan 10, 2013 12:38 am, edited 1 time in total.
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Re: Self tending jib sheet?

Postby PassingWind » Thu Jan 10, 2013 12:33 am

jdoorly wrote:Yes, I was speaking of the balanced jib idea, no, I wasn't thinking about the Hoyt balanced jib (I forgot about that). I was thinking about this boat: http://www.swallowboats.com/our-boats/open-boats/storm-17 There was a pic in a 2006 issue of Water Craft (U.K.).

The feature of the balanced jib is that you don't need much muscle or winch to pull it in even on larger boats, because it's BALANCED! :D

ooops, this is a better pic of the balanced jib: http://www.swallowboats.com/bayraider-17


I think the balanced refers to the fact that you have increased the jib size and shifted the jib forward. This balances the sails (main and jib) and reduces weather helm.. I dont think it will reduce any effort of trimming the jib
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Re: Self tending jib sheet?

Postby jdoorly » Thu Jan 10, 2013 1:00 am

PassingWind, you are correct about reducing weather helm for sure, but tell me this: Why do they say a rudder is 'balanced' when its center of axis is moved (up to 1/3 the way) aft of its leading edge? And, in the same way a junk rig is 'balanced' because a portion of the mainsail is forward of the mast with the larger portion aft of it. Of course there is a balance between sails as well, and a balance between sails and hull forces. And, so it goes...
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