G-Cat Jib question regarding zipper sleeve :: Catamaran Sailboats at TheBeachcats.com

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G-Cat Jib question regarding zipper sleeve

mrvideo

Rank: Lubber

Registered: Jun 22, 2015

Last visit: May 13, 2023

Posts: 26
Posted: Jan 06, 2022 - 08:38 PM

On a G-Cat 5.7 jib, how far "should" the zipper come down to the tack? I have one that goes all the way down and one that stops about 23" from the tack. Is there a prefrence?

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G-Cat 5.7
Sarasota
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shortyfox

Rank: Mate

Registered: Apr 07, 2017

Last visit: Nov 21, 2024

Posts: 367
Posted: Jan 07, 2022 - 07:26 AM

The 5.7 has a front cross beam about 2 ft aft of the bows. The tack of the jib is on the front beam but because of the bridle, the zippered luff has to stop at the top of the bridle just like every other beach cat. You might consider a hanked on jib especially if your 5.7 has a front tramp. So much easier.

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Bill Townsend
G-Cat 5.0
Sarasota
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MN3

Rank: Master Chief

Registered: Jun 20, 2006

Last visit: May 22, 2024

Posts: 7089
Posted: Jan 07, 2022 - 10:43 AM

mrvideoOn a G-Cat 5.7 jib, how far "should" the zipper come down to the tack? I have one that goes all the way down and one that stops about 23" from the tack. Is there a prefrence?

23 inches is pretty extreme for a zipper gap
typically they are full length

this might slightly impact the ability to get the correct shape in that part of the sail because it can pull aft when sheeted tight

I would think it also could lead to zipper failure if the stress on the zipper is too much due to that area not being secure

edit - thought about this last night - I don't really think there is too much chance it will lead to zipper failure but It could since the zipper will be unsupported at the tack and COULD cause stress/pull at the 2' mark - ymmv

Edited by MN3 on Jan 08, 2022 - 09:04 AM.
texastuma

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Registered: Nov 22, 2012

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Posts: 410
Posted: Jan 10, 2022 - 04:15 PM

mrvideoOn a G-Cat 5.7 jib, how far "should" the zipper come down to the tack? I have one that goes all the way down and one that stops about 23" from the tack. Is there a prefrence?

I agree with MN3, 23" is a bit much. The further down the zipper goes, the better the shape of the sail will be maintained. The zipper luff does help keep the luff in place. If that makes sense. With the zipper stopping 23" above the tack, this 23" will have some sag. Which is ok in light wind, but looks funky and not ideal when the breeze picks up. Typically, I will have a strap around the forestay a couple of inches above the tack to help absorb the load off the zipper. At this point, you may be able to add 2 of these straps in the 23" zone. Or, just leave it alone and go sailing.

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Scott

Prindle Fleet 2
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MN3

Rank: Master Chief

Registered: Jun 20, 2006

Last visit: May 22, 2024

Posts: 7089
Posted: Jan 10, 2022 - 04:34 PM

Quoteyou may be able to add 2 of these straps in the 23" zone.

or add a hank down there
shortyfox

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Registered: Apr 07, 2017

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Posted: Jan 10, 2022 - 08:35 PM

I must really be missing something with this discussion. Like I stated before. the luff on a G-Cat jib comes all the way down to the front cross tube and that is where the tack of the jib is attached. The bottom of that zipper has to stop right above the apex of the bridle which might be around 23 inches above the tack. That's the original design. The only exception might be if there's a furler involved, the drum has to go above the top of the bridle.

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Bill Townsend
G-Cat 5.0
Sarasota
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MN3

Rank: Master Chief

Registered: Jun 20, 2006

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Posts: 7089
Posted: Jan 11, 2022 - 12:10 PM

Quotethe apex of the bridle which might be around 23 inches above the tack.

huh? how can the bridal be above the tack of a sail? I assume you mean the bridal apex may be 23" above the front beam

QuoteThe bottom of that zipper has to stop right above the apex of the bridle

it doesn't "have to" be anywhere

it is best to be right above the tack but can be 3 or 4 inches about without any issue, conversely i have jib zippers that extend well past the tack of the sail (although not attached to anything and not a great design if using a furler)
bradinjax

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Registered: May 10, 2016

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Posted: Jan 11, 2022 - 01:47 PM

mrvideoOn a G-Cat 5.7 jib, how far "should" the zipper come down to the tack? I have one that goes all the way down and one that stops about 23" from the tack. Is there a prefrence?

Former G-Cat 5.7 owner here. The jib with 2 ft of material below the bottom of the zipper is the standard jib that is secured directly to the crossbeam. The jib that has the zipper all the way to the tack is for a roller furler. If you measure both luffs I believe you will find the full zipper jib to be about 2 ft shorter than the jib that has a "short" zipper. Hope this clears up some confusion.

Edited by bradinjax on Jan 11, 2022 - 02:07 PM.
MN3

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Posted: Jan 11, 2022 - 02:46 PM

QuoteFormer G-Cat 5.7 owner here. The jib with 2 ft of material below the bottom of the zipper is the standard jib that is secured directly to the crossbeam. The jib that has the zipper all the way to the tack is for a roller furler. If you measure both luffs I believe you will find the full zipper jib to be about 2 ft shorter than the jib that has a "short" zipper. Hope this clears up some confusion.

Great info! - and if the jib went to the beam, there would be less pull on the first few feet of sail (assuming the sheeting angle was close to mid point on the sail

Makes more sense
mrvideo

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Posted: Jan 17, 2022 - 02:38 PM

bradinjax
Former G-Cat 5.7 owner here. The jib with 2 ft of material below the bottom of the zipper is the standard jib that is secured directly to the crossbeam. The jib that has the zipper all the way to the tack is for a roller furler. If you measure both luffs I believe you will find the full zipper jib to be about 2 ft shorter than the jib that has a "short" zipper. Hope this clears up some confusion.Edited by bradinjax on Jan 11, 2022 - 02:07 PM.

You and shortyfox have cleared this up for me - I was a bit panicked that I told the sailmaker the wrong thing. So yes I do have 2 old sets of sails - I now see that one was for a roller jib (which I took off) and the other was for the "standard" design; zipper stopping 2' above tack to allow for bridal.

Thanks so much guys!

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G-Cat 5.7
Sarasota
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