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Old 25-05-2013, 09:30   #106
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Re: Rolling Hitch on Snubber

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In our discussion/debate I think it's important to simply realize there ARE two failure modes on both systems and there IS a system design trade-off and people CAN intelligently choose two paths in both.
It seems to me that one can mitigate both problems on snubbers, so there really isn't a trade-off. I have discovered that on my boat a 3/8" 3-strand nylon snubber held on with a modified rolling hitch does not snap and doesn't chafe enough to worry about. I can further reduce chafe to nill by going to another snubber I have attached to a bow eye down near the waterline. I suspect issues with snubbers are due to several factors: wrong rope construction and material, not enough stretch, way too short, and the wrong knot or hook. Another complication is where and how it is connected to the boat, possibly requiring heavy chafing gear. My normal daily snubber just runs from a cleat over the bow roller, with no additional chafing gear, and I have not had major issues with chafe. Probably worth replacing once a year or so in continuous use, or when it starts to show wear.

Morgan's Cloud has a good discussion too. Basically, what some of us have been saying--a long length of 3-strand nylon and a rolling hitch or chain hook.

Dashew too.
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Old 25-05-2013, 09:34   #107
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One thing I have thought about doing, specifically to the needs of dyneema, is to splice a large loop in one end of the dyneema that will allow me to tie my prusik knot and the other end has an eye with one of those new carbon eyelets spliced in. I could then have a hook spliced into my snubber line land have the best of both worlds. A quick and easy snubber setup and one I can also setup before my bow roller.
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Old 25-05-2013, 09:43   #108
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Re: Rolling Hitch on Snubber

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Originally Posted by estarzinger View Post
^^

One solution I thought about was a spectra cord loop with a klemheist around the chain, and rather than a sheet bend to the snubber line, using a tylaska trigger shackle.
That is exactly what I use, but I use an ordinary (but large to keep the radius of bend on the Spectra line better)
My bow roller is large and will pass the shackle, but as the spectra loop is a meter long you can stop the retrieval when the Klemheist is inboard, but before the shackle hits the bow roller. The shackle can then be pulled inboard (with the snubber) and easily undone. On deployment it is easy to ease the shackle over the bow roller. On both retrieval and deployment the pressure is on the chain, not on the snubber, or the shackle.

When the shackle has been undone and removed, the klemheist knot and specra line can be pulled further inboard so its easy undone.
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Old 25-05-2013, 09:44   #109
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Re: Rolling Hitch on Snubber

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It seems to me that one can mitigate both problems on snubber.
Obviously that's the end objective. And I think there are in fact several available solutions that are 'complete solutions'

But you always do pick one failure mode (consciously or not) as the primary, and then design the system to mitigate the secondary failure modes.

And, as an aside, it's actually a three fold trade-off in both cases, because there is the 'ease of use' factor also with both snubber and preventer systems.

And yes, I agree that nylon has been the conventional snubber choice for years. But as I have said several times now . . . extensive empirical experience (And insurance claims history) now suggests it is definitely not the best choice for mooring buoy pennants. That at least in that particular application the greater chafe vulnerability of nylon far far out weight's its greater elasticity (shock loading reduction) [especially in the same size and length].

And as I said just above . . . . if you pick a particular nylon line, I can in fact always pick a Dacron one that is exactly the same stretch as your nylon one. The Dacron one will be longer.

For the above two reasons, the 'nylon is the only option' argument just does not meet the sniff test to me.
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Old 25-05-2013, 09:56   #110
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Re: Rolling Hitch on Snubber

And no doubt the chafe issue will also depend on how much your boat veers and pitches in heavy conditions. Different boats may require different chafing gear or configurations.
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Old 25-05-2013, 10:33   #111
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Re: Rolling Hitch on Snubber

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Originally Posted by estarzinger View Post
For any given piece of nylon line, you could in fact choose a size and length of Dacron line that had exactly the same stretch.
Yes, you could, but why?! It would have to be awfully long and awfully thin (a lot thinner than what you've shown in your photos). Double braid polyester has about one-fourth the stretch of three-strand nylon of the same size, and one-fifth or less of that of octoplait. It only stretches 2.2% or so at 20% of its breaking strength, compared to about 10% for three-braid and quite a bit more for octoplait. So your 10 meter snubber would need to be 40 or 50 meters long? So you're going to attach it right at the anchor??

Polyester is fundamentally unsuited to use as a snubber. If your snubber doesn't stretch to absorb shock loads, it is not doing its job at all. This is a challenge not just to the snubber (like chafe is), but to the boat altogether (so comparing chafe and stretch is a false dichotomy). If your snubber doesn't snub, you might as well leave off the snubber altogether and just lie to your chain.
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Old 25-05-2013, 10:38   #112
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Re: Rolling Hitch on Snubber

Quote:
Originally Posted by estarzinger View Post
Obviously that's the end objective. And I think there are in fact several available solutions that are 'complete solutions'

But you always do pick one failure mode (consciously or not) as the primary, and then design the system to mitigate the secondary failure modes.

And, as an aside, it's actually a three fold trade-off in both cases, because there is the 'ease of use' factor also with both snubber and preventer systems.

And yes, I agree that nylon has been the conventional snubber choice for years. But as I have said several times now . . . extensive empirical experience (And insurance claims history) now suggests it is definitely not the best choice for mooring buoy pennants. That at least in that particular application the greater chafe vulnerability of nylon far far out weight's its greater elasticity (shock loading reduction) [especially in the same size and length].

And as I said just above . . . . if you pick a particular nylon line, I can in fact always pick a Dacron one that is exactly the same stretch as your nylon one. The Dacron one will be longer.

For the above two reasons, the 'nylon is the only option' argument just does not meet the sniff test to me.
Nylon has a serious drawbacks -- it loses strength when wet, and heats up and fails when subjected to constant cyclical loads. I would not use it for a an all-rope rode.

But it really is the only choice for a snubber -- just like -- ! -- for a dynamic climbing rope -- because it is the only kind of rope which stretches enough to provide reasonable snubbing at a realistic length and strength.

Does anyone use polyester for a dynamic climbing rope? Nope. Does any reasonable person use polyester for an anchor snubber? Same answer.
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Old 25-05-2013, 10:41   #113
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Re: Rolling Hitch on Snubber

Has anyone considered (or used) the 4wd snatchem straps for a snubber.
They are strong elastic and readily available.
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Old 25-05-2013, 10:56   #114
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Re: Rolling Hitch on Snubber

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That's what you get for trying to keep it cheap cheap cheap Test for minimum diameter with one solid brand and then stay with that brand.
I do agree. I would rather buy quality, but the cordage here is "no name" and sold by the kilogram.
Ordering via the UK is necessary to get a recognised brand name and unfortuantuantly I am not often in same place long enough to order stuff this way.
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Old 25-05-2013, 11:02   #115
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Re: Rolling Hitch on Snubber

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Originally Posted by noelex 77 View Post
I do agree. I would rather buy quality, but the cordage here is "no name" and sold by the kilogram.
Ordering via the UK is necessary to get a recognised brand name and unfortuantuantly I am not often in same place long enough to order stuff this way.
guys I thought you might be interested:
Mantus Bridle

this is a new product, that was designed with the idea of making snubbing a little easier and safer...
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Old 25-05-2013, 11:03   #116
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Re: Rolling Hitch on Snubber

Last summer I started using a loop of single-braid Dyneema with a Kleimheist. The nylon snubber attaches to the Dyneema with a large Wichard asymetric carbine hook (3170 lbs working load, 9900 lbs breaking load). The hook won't pass through the bow roller, but the Dyneema does. The hook attaches / unattaches quickly and easily, won't fall off, and won't jam if bent.

Would a piece of three-strand and a rolling hitch be cheaper and easier? Probably. I guess I like the the Dyneema's chafe resistance. Also, it grips like iron once you tension it, in part because you can use a smaller diameter line (mine is beefy at 3/8"). Then again, if I'm honest I'll admit that I went to this set up partly because it seemed like a cool experiment. I'll let you know if it fails.

I have to admit that I'm not 100% sold on a super long, stretchy snubber, especially if anchoring in relatively flat water. Our boat sails a bit on the anchor rode, and it seems like the rubber-band effect exacerbates the dynamic loading at the end of the lateral swing. Then again, I see the advantage of more elasticity when waves kick up. Like Evans says: the solution depends on how you define the problem: chafe or shock loading, gust/wave loading or dynamic oscillation loading (my terms, probably incorrect).
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Old 25-05-2013, 11:08   #117
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Instead of shackles or caribiners, you should use a soft shackle.

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Old 25-05-2013, 11:16   #118
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Re: Rolling Hitch on Snubber

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Originally Posted by Mantus Anchors View Post
guys I thought you might be interested:
Mantus Bridle

this is a new product, that was designed with the idea of making snubbing a little easier and safer...
What is the caribiner for?

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Old 25-05-2013, 11:19   #119
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Re: Rolling Hitch on Snubber

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Also, it grips like iron once you tension it, in part because you can use a smaller diameter line (mine is beefy at 3/8").
This is a great point.the combination of a high tech line and a loop so the strength is doubled, means the loop can be quite thin without breaking. This makes the loop much easier quicker and more pleasant to tie than a thick line.

It also helps it mold to the chain shape giving better grip. I have never had one break.

This is particuarly significant with thinner chain. Using G7 chain is great but wrapping a thick, salt encrusted and stiffened nylon snubber around this thin chain makes a snug knot difficult with thick rope.
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Old 25-05-2013, 11:33   #120
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Quote:
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Instead of shackles or caribiners, you should use a soft shackle.
+1

I use them for many things. Never thought to use them to tie a snubber. Only concern I would have is during slack lack of tension time, would it work itself loose? Sometime on our racing head sail we find the dyneema soft shackles work loose. Unusual, but not unheard of.
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