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 Post subject: Need some thinking caps
PostPosted: Tue Apr 29, 2014 6:11 pm 
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I've got a Nacra 5.0 jib that I'm going to use on the TI. Want it to be furlable, but it is currently hanked. Don't want to alter the sail, in case I need it for the Nacra. Sail has 2 large grommet holes at the ends and 6 hanks in between. No pockets for wires or pipe.

So far I tried cutting holes in the sides of 6, 1/2" pvc couplers, the size of the hanks. Connected the couplers with PVC. Ran 550 cord through the center, and connected the hanks to the cord, through the holes. Did a little test roll, lifted the roll from one end to put on the boat and snapped a coupling. Also broke one of the hanks.

Two problems. The size of the holes decreases the coupler strength too much, and when the PVC coupling rolls and contacts the hank (and continues to roll up the sail) it appears to be putting too much pressure on the plastic hanks.

So what I need is to figure out a different way to make this sucker furlable. Ideas? I haven't tried it but it appears that the hanks are screwed in, so they can probably be removed.


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PostPosted: Tue Apr 29, 2014 8:02 pm 
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Oof! That's unusual for a cat, I think.

It's like this?
Image

There are furling rigs that are offset for hanked sails on monohulls, where the luff is clipped onto the halyard. Like this:

Image

Don't recommend it. Hobie 16 and 14 turbo sails should be cheap and plentiful. You could use standard hardware (maybe even a racer's hand me downs) and change them out easier in the future.

Better performance too.


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PostPosted: Wed Apr 30, 2014 5:13 am 
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NOHUHU wrote:
Oof! That's unusual for a cat, I think.

It's like this?
Image

There are furling rigs that are offset for hanked sails on monohulls, where the luff is clipped onto the halyard. Like this:

Image

Don't recommend it. Hobie 16 and 14 turbo sails should be cheap and plentiful. You could use standard hardware (maybe even a racer's hand me downs) and change them out easier in the future.

Better performance too.


Image
That's exactly like how they are.

I was looking at that bartonmarine image yesterday, thinking I could make my own. You don't recommend that set up?

The cheapest/only Hobie 16 jib I could find in my area is $220. While cheap in the grand scheme of things, I was trying to reuse what I had to save a large percentage on the cost on this project. It's also an hour plus away in Austin.


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PostPosted: Wed Apr 30, 2014 1:06 pm 
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You maybe could have a sleeve sewn on. Or I've seen where some guys DIY'd it with full length sched 40 pipe on the wire, with small holes cut for the hanks. You could try that, but overall it seems an awkward and non aerodynamic approach.

Maybe ebay or the the local sailing clubs can source you a jib. The boards here at Hobie list them too…maybe post a request?

In my experience, almost every cat owner has a spare jib due to the need for speed, or image enhancement. Sometimes they are blown out, but that's not a big deal for this experiment.


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PostPosted: Wed Apr 30, 2014 1:32 pm 
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I could try larger diameter PVC. My last attempt was 1/2 schedule 40 with the cuts for the hanks made in couplings. But I would think cuts in the pipe itself would be even weaker.

I'll keep looking for another sail, but I'd really rather not have to purchase another, and I definitely don't want to alter the one's I have in case I need to sell the Nacra

I was thinking, worst case scenario I could get my wife to stitch up a sail bag from some of my old army uniforms or something. I could have it such that the bag remained below the sail, and I could just leave the sail hanked...

This would mean a few things though.
I would be less inclined to use the jib when sailing by myself, which is what I do mostly.
I'd have less ability to tinker with sail size and attachment points along the bowsprit. Basically I would either have a 40 sq ft genoa that overlapped the main or a 40 sq ft jib out front...


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PostPosted: Wed Apr 30, 2014 1:47 pm 
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Find a sail with a zippered luff. I was able to use schedule 80 3/4 in the luff with no wire and the shackles connected directly to the PVC. Simple and effective....furrles very easily. It will be well worth the investment in a separate sail.

These are the two shackles directly connected to the PVC.Image


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PostPosted: Wed Apr 30, 2014 2:00 pm 
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Yes, the hanks would be fine, if you had permanent forestay, a full deck and a deckhand. Otherwise,..

I respect your goal of "git her done" as opposed to the lofty goal of "advancing the design" so check out this guys approach, using 3/4" PVC:

Image

http://www.reocities.com/felixthefish.geo/Jib_furler/Jib_furler.html

Other folks have posted similar instructions.


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PostPosted: Wed Apr 30, 2014 4:40 pm 
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That's basically what I did, with 1/2". Using a larger diameter without couplings might work but, as you mentioned, it doesn't appear to be the most aerodynamic thing in the world. Also, the side of the holes are still putting stress on the plastic hanks when furling/furled. One of my hanks broke as well for that reason. Might have been that 1/2" was the perfect size to put the stress exactly at the weakest point of the hank...I don't know. I'm sure I'll be paying more for the shipping than I will be for a new hank.

Unless I can manage to MacGuyver this sail or get another for next to nothing I'll probably sideline the project.


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PostPosted: Wed Apr 30, 2014 7:18 pm 
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Yeah, and it probably would sound like one of those Peruvian pan-pipes when you beat upwind.


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PostPosted: Wed Apr 30, 2014 7:32 pm 
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I love the hum the Nacra makes when her sails are set right and she starts picking up the pace. A bit of a different origin though, huh.


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PostPosted: Tue May 20, 2014 7:17 am 
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Talked to the sailmaker the other day. He's sending me a new hank for free. Said the part was so cheap it wasn't even worth the invoice. His suggestion was to cut PVC down longitudinally and slide the luff in, hanks and all. Unfortunately I don't know how I could do that cut myself with any precision, and the PVC would have to be really large in diameter.

There is a local that sews custom marine "stuff," that said she has sewn sails but would not even venture a ballpark quote on sewing in a pocket on the luff.

Grrrrrr


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PostPosted: Tue May 20, 2014 9:49 am 
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,,, you could make a jig out of some old lumber to hold and clamp the PVC to

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PostPosted: Fri Jun 13, 2014 2:01 pm 
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So I figured out how to use my hanked sail, while looking for one I can furl:

Ran across something called a Gerr downhaul. Set up like this Image

So I rigged up a forstay. Attached the jib and added a halliard (green) and downhaul (red).

Image
With slack in the downhaul I can run up the jib and, in this test, use my nacra jibsheet to control the jib.

Image

If I keep the halliard cleated, uncleat the jibsheet and pull the downhaul it bunches the jib up against the forstay. In this picture it's bunching low, but this is because one of my hanks is broken. Once fixed the point at which it bunches the jib will be higher.

Image

I can then uncleat the halliard and the jib bunches up into a ball at the bow.

Image

Or, I can drop the jib straight down by leaving the jibsheet cleated, uncleating the halliard and pulling the downhaul.

I plan on taking one of my old army duffle bags and making a jib bag that stays on the deck. It will have grommet holes for lines to run through it and keep it in place, and a zipper along the top. To use the jib all I have to do is unzip the bag and pull on the halliard. When dowsing it, it will go back down into the bag without me or my passenger having to go forward. At the end of the day all I'll have to do is zip up the bag and be on my merry way.


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PostPosted: Sun Jun 15, 2014 8:24 am 
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Question for those that have added a jib. Yall have stated that the main mast is designed to flex to the sides and back, but NOT forward, hence the rear stay. I have a rear stay which is 3/8 diamond braided nylon rope. I tensioned it such that the mast could not flex forward. My driveway is not level and the mast naturally leaned forward, so I just tensioned the rear stay until it pulled the mast back perpendicular to the hull. I don't know how much flex this rope has but it isn't supposed to flex much. How did you decide how to tension your rear stay?

In order for me to use the hanked jib I've had to add a forstay. I used the same 3/8 diamond braided nylon rope as I did for the rear stay, and left slack in it so that the mast could still flex to the rear. However, having left slack in the rope it appears that the twist-on hanks can undo themselves when hauling up or bringing down the jib. I'm assuming this is partly because they're meant for braided metal, not nylon rope. The easiest answer would be to change the hanks to something closed but finding such a thing, that can be purchased in the US has been difficult so far. The attaching point to the sail has to be a small screw, nothing larger. I can't use those brass piston hanks.

In order to use the twist-on hanks I suppose I could use a length of braided metal and then a section of rope that has some stretch to it to keep the hanks on the forstay as well as allow the mast to flex to the rear? Do you think this would limit the rearward flex of the mast and effect performance?

Also, for the halyard, what is the hardware called that takes the line from above and turns it on a roller 90 degrees aft? I'd also need to mount one on the bowsprit for the downhaul. I've seen some that have the roller and then within the same housing have a cleat. Not a cam cleat but the kind that we use to hold the "UP" line for our rudders on the TI. That might be doable, and would require 2 less cam cleats somewhere aft, saving those predrilled spaces on the TI crossbar for cam cleats for my jib sheet.

Final question. When adding the mast topper I noticed that the black mast cap that holds the 1 inch webbing at the top of the sail was not fixed to the mast. It appeared that that it used to be glued, but now spins freely. I'm not sure if it's an issue, but last time I was out sailing (without any of the above modifications on) I noticed that the top of the sail was not shaped correctly. Does that black cap need to be glued to line the top of the sail up with the bottom of the sail? (The bottom part that has the line to pull the sail down tight) I hope that makes sense...

Appreciate the help.


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PostPosted: Tue Jun 24, 2014 2:55 pm 
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Nada? Hmmmm.... topic all played out or something?


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