Frankenstein JIB project: HOBIE 17 meets Nacra 5.8 HELP please if you own a Nacra 5.8

rojoyinc

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Registered: Jun 29, 2013

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Posts: 7
Posted: Jun 01, 2014 - 03:02 PM

I picked up a H17 last fall all in parts and started putting it together this year. The "added mod of a jib" to make it similar to a 17 sport... seems to use a crossbar from a Nacra 5.8.

I installed it - but I have never seen how they install or look or work on a Nacra, so I'm kinda guessing by trial and error. (I had it backwards and upside down before this).

Hobie forums not much help due to this being a Nacra front end. A very experienced Hobie friend said DONT SAIL IT like this. It will break the cross bar. He seems to feel it needs a bridle to the furler like my 18SX. But this furler has no such attachments.

Can someone send me a photo of their front end all rigged to go? Does this look right? Is is safe? do I need a bridle?

Ron@portranet.com

So sheeting in the main hard - will I break that front cross bar? My 18SX has no cross bar, but bridle wires on the furler. As does my Tiger. I think I need advice of a Nacra sailor.

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Ron Grand Rapids, MI
Fleet #519
West Michigan Catamaran Sailors

2000 Hobie 18SX
1984 Hobie 16 restored, new sails and spinnaker.
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CatsailorMike

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Posted: Jun 01, 2014 - 04:09 PM

Ron, that looks like a Harken 434 furler, which is what my son has on his h16. If you're planning on using it, I'd suggest a bridle and at the center use a 1/4 inch shackle upside down with the pin through the bottom tabs on the furler. No issues in 14 years on the H16. A friend of mine, popeyez7, has a 17 with a big jib. Not sure of his setup but I'll let him know about your dilemma and hopefully he'll chime in. I'll get you a pic of the setup on my boat.

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Mike Conway
H16
Hilton, NY
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rch701

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Posted: Jun 01, 2014 - 04:11 PM

Well, as a cat sailor, I am not sure how you are supposed to add a jib. But as a mechanical engineer, your setup looks great. The inverted dolphin striker will take the tension load. It adds compression to the cross beam, and it take all of the side load (such as a bridle setup) off the hulls. I see nothing but win win win.

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FYC, Nacra 5.2 "Chris's Flyer" & Nacra Playcat & Farrier Tramp
Previously owned: Trac 14, H14, H16, H18, N5.0, G-cat 5.0
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Dogboy

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Posted: Jun 01, 2014 - 05:48 PM

I responded to your previous questions on the Hobie forum. You want the bow foil flipped the way you have it and you do not need a bridle with that configuration because the inverted dolphin striker takes the loads that bridle wires would take. However something I noticed is the way you have the foil pinned to the bow tangs does not look good. The pin needs to be supported on both sides (double shear) you only have the pin supported on one side - think shroud chain plate, the shroud adjuster sits on both sides od the shroud anchor on the hull and then the pin goes through and is supported on both sides. The way you're set up, the pin is in single shear so it will have less load handling ability plus if something shifts, the pin could bend and/or put the load on the split ring.

Also, you have that bow foil rigged so low that if the bow dives into even a small wave, the foil is going to cause a lot of drag.

sm
jackb

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Posted: Jun 01, 2014 - 05:48 PM

You really need a bridle setup, as it is intended for H17 sport. Rob is correct -- in theory it should work. But you will be taking chances. The cross bar was intended a a compression, rather a bending member.

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Jack B
Hobie 17
BC, Canada
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bacho

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Posted: Jun 01, 2014 - 08:00 PM

I don't see why you would need a bridal. The cross bar takes the place of one.

Ideally, I think you want a "softer" connection of the bar to the hulls. I think a short piece of cable would be preferable to allow everything to flex some.

At the very least, replace those pins with bolts. They will not work well at all loaded in single shear like that.

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Greenville SC

Offering sails and other go fast parts for A-class catamarans
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HULLFLYER

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Posted: Jun 02, 2014 - 05:25 AM

If a Nacra 6.0 NA does not need a bridal wire set up using the bow foil, with its huge jib, why would a much smaller Hobie 17 need one. You can use 7 or 10 hole shroud adjusters between the hulls and foil, and it should be fine. The roller furler setup in picture 1 is just like we did on 6.0s. If anything it is over kill compared to the set up on a Hobie 17 sport.
By the way the nacra bow foil is very hard to come by these days, it was a goof find for you.
bacho

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Posted: Jun 02, 2014 - 06:40 AM

7 hole adjusters is a better idea than cables.

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Greenville SC

Offering sails and other go fast parts for A-class catamarans
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CatsailorMike

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Posted: Jun 03, 2014 - 05:51 AM

Ron, here's the furler on my H16 with the shackle as i mentioned. No problems with it. Good luck

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Mike Conway
H16
Hilton, NY
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the-renovator

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Posted: Jun 03, 2014 - 04:19 PM

With your set-up above, if the mast is raked correctly, then leave it as is and sail it, maybe add stainless steel lock-nut and bolt in place of the clevis pins on bow tangs, will lock the foil into place. If you start adding stay adjusters then you will have to shorten the forestay accordingly. The 5.5 setup has short bridal wires between foil and hulls, one on each side, and a 10-hole stay adjuster, no furler . The foil is designed to replace the bridal wires, it prevents the nose of the hulls from being pulled inward towards each other when there are large loads on the over-sized jib of the 5.5.

http://www.thebeachcats.c…296&g2_imageViewsIndex=1
azcat

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Posted: Jun 03, 2014 - 06:11 PM

IMHO , don't ever use a bolt in place of a pin. Unless the shoulder of the bolt extends all the way through the items being bolted,The SS threads will grate against the ALU of the furler attachment point, and the hole in the shackle that the threads are passing through. Also, the threads give a natural break point that will cause the bolt to fail when fatigued under load. Use a pin. A threaded bolt has a fraction of the strength of the same size pin.

The attachment point at the bow tang as it is currently will fail very quickly. Do not sail with it in its current config. Use a stay adjuster and PIN IT with the correct size pin. 1/4 I believe. Tape the ring. The stay adjuster allows the foil to reside high enough that when you bury the bows, it doesn't make things worse. Shorten the forestay if needed, it's a few bucks and a couple minutes.

Edited by azcat on Jun 03, 2014 - 06:19 PM.
beachsailor

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Posted: Jun 04, 2014 - 07:08 AM

If you look at the N6.0 the bridle foil is attached to the bows using wire. This is a pic of the N6.0 wire. http://www.murrays.com/02-4715-22.html.
By using wire it allows the hulls to flex but still keeps the loads pulling up(not trying to pull the bows in). The other advantage of moving the foil up is it keep the foil out of the water if you stuff the bow or push the bows thru a wave.
The H17 was designed as a uni rig with the twin forestays running up to the mast tang. Thus reducing inward loads on the hull. That is the reason the bow foil or spreader bar is required.

Edited by beachsailor on Jun 04, 2014 - 07:10 AM.
CatsailorMike

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Posted: Jun 04, 2014 - 12:23 PM

Agreed azcat, the shoulder goes to the outside of the shackle body and threads are covered completely by the nylok nut. Been using the bolt because I'm too lazy to go to West Marine for a longer pin.

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Mike Conway
H16
Hilton, NY
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popeyez7

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Posted: Jun 04, 2014 - 01:57 PM

~~ Hello Ron... I wanted to get up here a few days ago,, Messing with trl lights--GGGRRR !!!! I have 2 friends with 17 Hobies w/ ''sport jibs''... I have a ''Super jib'' and the set up is a little different. I'll show theirs first.. Lets see if I can do this ??
~~ Now this ones mine with the ''super jib'' (yellow boat)~~ My bar is different and it goes right to the hull. Having a bigger jib on it is more pressure on the hulls... My jib goes about 20-25% past the mast. It has a hell of alotta more HP.. The other yellow beast is my 18 Mag... My 17 will give that a hard time with the bigger jib, BUT the 17 is a one man boat and another lite person ''might'' be good,,, I've yet to find out !!!~~ Yours might be ok for this year, but I'd think about gettin the right one for it...

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~ Vietnam Vet 69-71~ 17 Hobie w/big jib, ~18 Hobie mag,~DN Ice sailor,
and other toys.......
~~ I live in NY state on the north shore of Oneida lake in
Bernhards Bay. ~~~~~~
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