Which line absorbs the most force? - SailNet Community
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post #1 of 13 Old 03-18-2012 Thread Starter
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Which line absorbs the most force?

A spring/summer project I may do this year is to replace my anchor's snubber. The previous owner fabricated a nice strong attachment point at the stem waterline where the bobstay attaches. He had some double braid line (nylon or poly, I can't tell for sure) spliced to it for a snubber/bridle.

I'd like to replace it with something more stretchy to help avoid shock loads from the anchor in a major blow. Which line is best for absorbing shock, or more accurately, distributing the load over time?

Nylon or polyester 3strand?
Nylon double braid?
6 or 8 plat poly or nylon?
Something else?

The line will be about 12feet long and I'll also put a rubber dock snubber or loops of shock-cord in line on the line itself.

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post #2 of 13 Old 03-18-2012
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Re: Which line absorbs the most force?

For an application such as yours polyester basically does not stretch, 3 strand nylon would be your best bet. However with such a short piece of line you will not get a lot. The rubber snubber will be more useful.
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post #3 of 13 Old 03-18-2012
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Re: Which line absorbs the most force?

As stated, 12 feet won't get you a lot. If the notion is to absorb the impact of waves, then I would think you need 3-4 feet of stretch at working loads. While at high load nylon stretches as much as 30% before failure, you probably want to work in the 10% range, meaning 30 feet is better.

I have a 16-foot bridle, and since I changed to all chain I've noticed it doesn't do much for waves if it's rough; the chain gets straight and it jerks. I have a 60-foot bridle to use when in an exposed spot. I part, this is because I generally am in shallow water without much chain out.

Definitely nylon. Technically 3-strand stretches a little more than braid; in fact, the core of climbing ropes is laid (50% right hand, 50% left hand, to prevent spinning and internal hockling), not braided, for that reason. But double braid will work fine, you just need a bit more.

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post #4 of 13 Old 03-18-2012
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Re: Which line absorbs the most force?

Three strand nylon.

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post #5 of 13 Old 03-18-2012 Thread Starter
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Re: Which line absorbs the most force?

What about plaited line? *plait or 6 plait. How does it compare to 3 strand?

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post #6 of 13 Old 03-18-2012
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Re: Which line absorbs the most force?

3 strand nylon and you might want two set ups. One that is about 3 feet over the bow for normal everyday use, this can be a little thinner.

The second one is for storms and should be 20 - 30 feet over the bow and heavier.
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post #7 of 13 Old 03-19-2012
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Re: Which line absorbs the most force?

From my experience 3 strand nylon is the way to go. I have conducted no tests.

Just use a rolling hitch around the chain and feed it over the bow roller to a cleat. A bridle is a little fussy for me.

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post #8 of 13 Old 03-19-2012
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Re: Which line absorbs the most force?

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Originally Posted by TQA View Post
3 strand nylon and you might want two set ups. One that is about 3 feet over the bow for normal everyday use, this can be a little thinner.

The second one is for storms and should be 20 - 30 feet over the bow and heavier.
I would agree entirely with this, although my longer one is about 18' only; and the shorter one is about 5' off the bow.
I attach them through a shackle under the bow roller so there is zero chafe, zero noise. Just check the shackle now and then.

Best advice though from TQA


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Last edited by St Anna; 03-19-2012 at 06:29 AM.
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post #9 of 13 Old 03-19-2012
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Re: Which line absorbs the most force?

I might add that a good length of chain also helps absorb shocks. I realize this is somewhat counterintuitive, however, the weight of the chain causes it to resist lifting up off of the bottom and/or stretching straight. The bow in the chain acts to absorb much of the shock, both because it takes a lot of force to straighten a chain rode and because if the fluid dynamic resistance as it moves through the water. Adding a good-sized weight (i.e., a kellet) to the rode enhances the effect.

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post #10 of 13 Old 03-20-2012
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Re: Which line absorbs the most force?

Med, AFAIK 3-strand has the most stretch, which is why it IS preferred for dock and anchor lines. It is very much line a torsion bar, as you pull the strands untwist, yielding to the load. Then they come back, tightening again. To get more shock absorption, you woul dneed a real snubber (heavy "rubber" section) or improvise with a small auto coil spring from a junkyard, in something like a PVC pipe sleeve to hide it and make it pretty.
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