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Amsteel question

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  • brendamcguinn
    My boyfriend had a question I was hoping someone might could answer. We are planning to do some hammock camping this spring. David has been playing around
    Message 1 of 7 , Feb 23, 2013
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      My boyfriend had a question I was hoping someone might could answer. We are planning to do some hammock camping this spring. David has been playing around with some different hanging systems. He wants to use Amsteel rope to cut down on weight while keeping strength. He read that tying knots in Amsteel rope would degrade its strength. What he was wondering was is the strength effected only while the rope was tied or if even after the knot was taken out does the rope remain weaker. Since the rope is being used to hang hammocks it will be supporting a person's weight overnight and taken down the next morning. I was just wondering if anyone out there has any experience with that kind of rope.
    • Tom M. Blenko
      The efficiencies one usually sees quoted are based on breaking strengths of a length of rope with a knot tied in it. I don t know of anyone who has done the
      Message 2 of 7 , Mar 2, 2013
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        The efficiencies one usually sees quoted are based on breaking strengths of a length of rope with a knot tied in it. I don't know of anyone who has done the other test you mention, that of determining how the strength of a length of rope is affected after a knot has been tied, used, and removed. (Might be hard to specify since I assume the "used" part is the biggest factor in the result). I assume that the breaking strength/efficiency goes up a lot when the knot is removed.

        Although it was some years ago, I used only hammocks for camping for quite a few years, including in rainy and cold/snowy conditions. I evolved from building hammocks myself in situ to building hammocks in a reusable form to using commercial products.

        The best option, in my experience, from a weight and strength point of view is one of the commercial net hammocks available from camping supply stores. These are use a thin braided net constructed from artificial material. They are small (fit in your pocket, in principal), very light, they retain little moisture if they get wet (and can be wrung out). They are not as comfortable as some other hammocks I've used because they wrap themselves around you and it is difficult, e.g., to roll from one side to the other once in the hammock. They are the easiest hammocks to set up and take down.

        The other endpoint I reached in my evolution was a simple "canvas" hammock. Made from artificial material but in a very simple style, as I believe I've seen for ship's hammocks. A square piece of material with some number of grommets across either end. Individual lines from the grommets on each end attach to a ring. Leads attach on each end to the ring. These are probably stronger than the net hammocks, they probably weigh 3-4 times as much, they do not absorb water but do not shed it either. Pretty easy to hang but not as easy as the net hammock (which I am comfortable putting up in the dark when it's rainy). You can easily add a spreader at the head and foot if that makes it more comfortable for you.

        Either if these is easily lighter than the handmade hammocks (and some other commercial ones) I've tried. Artificial line is very strong but it is also pretty heavy, for a given diameter.

        Strength has never been an issue for me. If you weight 200 lbs, you need to use line with a 600 lb. breaking strength to attach the hammock but if within the hammock proper the weight tends to be distributed so you probably can get away with a lot less. That's why the net hammock can be so thin and light.

        Tom


        On Feb 23, 2013, at 7:46 AM, brendamcguinn wrote:

        > My boyfriend had a question I was hoping someone might could answer. We are planning to do some hammock camping this spring. David has been playing around with some different hanging systems. He wants to use Amsteel rope to cut down on weight while keeping strength. He read that tying knots in Amsteel rope would degrade its strength. What he was wondering was is the strength effected only while the rope was tied or if even after the knot was taken out does the rope remain weaker. Since the rope is being used to hang hammocks it will be supporting a person's weight overnight and taken down the next morning. I was just wondering if anyone out there has any experience with that kind of rope.
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      • Peter Hennessey
        Assuming you are using small to medium trees as the anchors, something to consider is the effect the line will have in damaging the bark. You might like to use
        Message 3 of 7 , Mar 3, 2013
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          Assuming you are using small to medium trees as the anchors, something to consider is the effect the line will have in damaging the bark. You might like to use something like this to spread the load - http://ukhammocks.co.uk/shop/article_27/Tree-Saver-Straps-25mm.html?pse=apq

          Sent from an iPad

          On 3 Mar 2013, at 01:54, "brendamcguinn" <brendamcguinn@...> wrote:

          > My boyfriend had a question I was hoping someone might could answer. We are planning to do some hammock camping this spring. David has been playing around with some different hanging systems. He wants to use Amsteel rope to cut down on weight while keeping strength. He read that tying knots in Amsteel rope would degrade its strength. What he was wondering was is the strength effected only while the rope was tied or if even after the knot was taken out does the rope remain weaker. Since the rope is being used to hang hammocks it will be supporting a person's weight overnight and taken down the next morning. I was just wondering if anyone out there has any experience with that kind of rope.
          >
          >


          [Non-text portions of this message have been removed]
        • rons_hobbies
          Following Peter s link led me to this site you might also find helpful in addition to the fine 1st hand experience provided by Ton:
          Message 4 of 7 , Mar 3, 2013
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            Following Peter's link led me to this site you might also find helpful in addition to the fine 1st hand experience provided by Ton:

            https://www.hammockforums.net/

            Ron

            --- In knottyers@yahoogroups.com, "brendamcguinn" <brendamcguinn@...> wrote:
            >
            > My boyfriend had a question I was hoping someone might could answer. We are planning to do some hammock camping this spring. David has been playing around with some different hanging systems. He wants to use Amsteel rope to cut down on weight while keeping strength. He read that tying knots in Amsteel rope would degrade its strength.

            <Snip>
          • Kathlean
            Knots in rope generally create an area of lower resilience immediately after the knot. Just like baseballs have a core of rubber-band material so they can
            Message 5 of 7 , Mar 3, 2013
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              Knots in rope generally create an area of lower resilience immediately after the knot. Just like baseballs have a core of rubber-band material so they can "bounce back," good rope has the ability to stretch a little when it experiences a sudden shock-weight. But in that spot right where the length of rope meets the knot, the resilience, the ability to take a sharp yank and then rebound, is drastically reduced.

              To answer your concern; unless the rope has been kinked or deformed by the knot tied in it, or the knot was left in for a long period of time, it should be unaffected once it's been untied. Just like always, if you exceed the weight-limit of the rope (what the manufacturer tells you), ASSUME it is damaged and don't trust it with your weight.

              When I sleep with camping hammocks, I usually use flat straps around the trunk of the tree, which saves the tree from damage and provides a better grip. For the rest, I use cord specifically designed for the purpose--I'm all about reading the manufacturer's directions when it comes to life-safety!


              > On Feb 23, 2013, at 7:46 AM, brendamcguinn wrote:
              >
              > > My boyfriend had a question I was hoping someone might could answer. We are planning to do some hammock camping this spring. David has been playing around with some different hanging systems. He wants to use Amsteel rope to cut down on weight while keeping strength. He read that tying knots in Amsteel rope would degrade its strength. What he was wondering was is the strength effected only while the rope was tied or if even after the knot was taken out does the rope remain weaker. Since the rope is being used to hang hammocks it will be supporting a person's weight overnight and taken down the next morning. I was just wondering if anyone out there has any experience with that kind of rope.
              > >
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              > > ------------------------------------
              > >
              > > Yahoo! Groups Links
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              >
            • Peter Hennessey
              Something which I haven t seen anyone discuss but which seems pertinent to me is the effect of sag in the hammock on the tension in the lines. The maths get
              Message 6 of 7 , Mar 4, 2013
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                Something which I haven't seen anyone discuss but which seems pertinent to me is the effect of sag in the hammock on the tension in the lines. The maths get terribly complicated, but a simple diagram taken from lifting sling spread tables shows the effect.

                As you can see, if you rig your hammock nearly flat, the tension in the lines is 11.49 times the applied load. While modern lines can probably accept this loading, old fashioned tree bark probably can't ! Factor in some shock loading from rough use and things get way out of hand!

                Happy camping, Peter H.
                Sent from an iPad

                On 3 Mar 2013, at 01:54, "brendamcguinn" <brendamcguinn@...> wrote:

                > My boyfriend had a question I was hoping someone might could answer. We are planning to do some hammock camping this spring. David has been playing around with some different hanging systems. He wants to use Amsteel rope to cut down on weight while keeping strength. He read that tying knots in Amsteel rope would degrade its strength. What he was wondering was is the strength effected only while the rope was tied or if even after the knot was taken out does the rope remain weaker. Since the rope is being used to hang hammocks it will be supporting a person's weight overnight and taken down the next morning. I was just wondering if anyone out there has any experience with that kind of rope.
                >
                >


                [Non-text portions of this message have been removed]
              • gerald diamond
                I don t have your diagram but I think you must have a unit problem here. Did you start with kilos and end up with newtons? ... [Non-text portions of this
                Message 7 of 7 , Mar 5, 2013
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                  I don't have your diagram but I think you must have a unit problem here.
                  Did you start with kilos and end up with newtons?






                  >________________________________
                  > From: Peter Hennessey <peterwhennessey@...>
                  >To: "knottyers@yahoogroups.com" <knottyers@yahoogroups.com>
                  >Sent: Monday, March 4, 2013 2:48:32 PM
                  >Subject: Re: [KnotTyers] Amsteel question
                  >
                  >

                  >Something which I haven't seen anyone discuss but which seems pertinent to me is the effect of sag in the hammock on the tension in the lines. The maths get terribly complicated, but a simple diagram taken from lifting sling spread tables shows the effect.
                  >
                  >As you can see, if you rig your hammock nearly flat, the tension in the lines is 11.49 times the applied load. While modern lines can probably accept this loading, old fashioned tree bark probably can't ! Factor in some shock loading from rough use and things get way out of hand!
                  >
                  >Happy camping, Peter H.
                  >Sent from an iPad
                  >
                  >On 3 Mar 2013, at 01:54, "brendamcguinn" brendamcguinn@...> wrote:
                  >
                  >> My boyfriend had a question I was hoping someone might could answer. We are planning to do some hammock camping this spring. David has been playing around with some different hanging systems. He wants to use Amsteel rope to cut down on weight while keeping strength. He read that tying knots in Amsteel rope would degrade its strength. What he was wondering was is the strength effected only while the rope was tied or if even after the knot was taken out does the rope remain weaker. Since the rope is being used to hang hammocks it will be supporting a person's weight overnight and taken down the next morning. I was just wondering if anyone out there has any experience with that kind of rope.
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