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Re: [Hammock Camping] How tight? What Angle?

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  • jwj32542
    ... got ... calculate ... I m having a hard time understanding this. The force exerted on a hammock line is broken into X and Y components. In a 2D view, the
    Message 1 of 16 , Dec 6, 2004
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      --- In hammockcamping@yahoogroups.com, Ralph Oborn
      <Ralph.oborn@g...> wrote:
      > I took the physics too (actually got the degree) . So when I first
      got
      > on the group I made a spreadsheet (under files) so you can
      calculate
      > the forces.

      I'm having a hard time understanding this. The force exerted on a
      hammock line is broken into X and Y components. In a 2D view, the
      sum of X and Y must equal the total force. The vertical forces
      equal weight/2, which makes sense, but in your spreadsheet the total
      forces do not equal X+Y. Why not? Why does that formula apply to
      the horizontal forces?

      It's also important to note that those are static calculations. The
      weight of you plopping down into the hammock can result in a dynamic
      force much greater than your weight when lying still.

      Jeff
    • zippydooda
      I opened the file and will have a look. Thanks. It is a Speer type, double layer, 1.1 oz ripstop. It is gray. (That was a joke). The rope is some cheesy
      Message 2 of 16 , Dec 6, 2004
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        I opened the file and will have a look. Thanks.

        It is a Speer type, double layer, 1.1 oz ripstop. It is gray. (That
        was a joke). The rope is some cheesy fat rope we had lying around.
        I doubt it stretches much under my 165 lbs. But it is not as easy to
        tie tight as thinner rope would be, so I need to make allowances for
        that.

        Does 8.0 refer to the total length of your hammock body after it is
        finished?

        I know that I need to try it myself, and that there are lots of
        variables. I am just looking for a starting point.

        And Ralph, speaking of wives, I was imagining hanging mine too tight,
        having it rip in half, and my wife laughing her head off.

        Thanks again, everyone. If it ever quits raining I will actually use
        this thing...

        Bill in Houston

        --- In hammockcamping@yahoogroups.com, "Dave Womble" <dpwomble@y...>
        wrote:
        >
        > Bill,
        >
        > I have some info in my folder (Youngblood) in the files section.
        The
        > dimensions I give are after stretch, so like was previous posted it
        > does change a tad depending on the amount of stretch you get. With
        > my Speer class hammocks, with my weight and using 1/4" hollow braid
        > polypro rope, I would guess that I am getting about 10% stretch and
        I
        > allow for that when I hang my hammock by shortening the support
        > ropes. I can usually pace off the distance between supports and
        get
        > it hung pretty close on the first try. What kind of hammock are
        you
        > using?
        >
        > Youngblood
      • Dave Womble
        ... Yes, that is the way Ed Speer defines his hammock. It is the distance between the hammock knots, measured along the sides. You are right about static load
        Message 3 of 16 , Dec 6, 2004
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          --- In hammockcamping@yahoogroups.com, "zippydooda" <zippydooda@y...>
          wrote:
          >
          > Does 8.0 refer to the total length of your hammock body after it is
          > finished?

          Yes, that is the way Ed Speer defines his hammock. It is the
          distance between the hammock knots, measured along the sides.

          You are right about static load versus dynamic load. Most of these
          light weight backpacking hammocks are not designed to handle heavy
          dynamic loading. Be careful how you use them and what you use them
          for.

          Youngblood
        • Ralph Oborn
          Yes and no! The forces (x and y) do not have to add up to the total force. Sorry that is just how vectors work. The vertical force on each end are weight/2
          Message 4 of 16 , Dec 6, 2004
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            Yes and no!

            The forces (x and y) do not have to add up to the total force. Sorry
            that is just how vectors work. The vertical force on each end are
            weight/2 assuming you are right in the middle, but the total load
            (tension on the rope) can be many times higher. You are also correct
            that this is just the static load, as Dave and others point out
            dynamic load while getting in and out may be much higher.

            As a thought experiment to understand how the rope tension may be much
            higher than the load imaging the empty hammock strung tightly between
            two sturdy trees. The vertical load is almost zero, but the almost
            horizontal tension may be hundreds of pounds.

            Ralph


            On Tue, 07 Dec 2004 00:52:00 -0000, jwj32542 <jwj32542@...> wrote:
            >
            >
            > --- In hammockcamping@yahoogroups.com, Ralph Oborn
            > <Ralph.oborn@g...> wrote:
            > > I took the physics too (actually got the degree) . So when I first
            > got
            > > on the group I made a spreadsheet (under files) so you can
            > calculate
            > > the forces.
            >
            > I'm having a hard time understanding this. The force exerted on a
            > hammock line is broken into X and Y components. In a 2D view, the
            > sum of X and Y must equal the total force. The vertical forces
            > equal weight/2, which makes sense, but in your spreadsheet the total
            > forces do not equal X+Y. Why not? Why does that formula apply to
            > the horizontal forces?
            >
            > It's also important to note that those are static calculations. The
            > weight of you plopping down into the hammock can result in a dynamic
            > force much greater than your weight when lying still.
            >
            > Jeff
            >
            >
            >
            >
            >
            > Yahoo! Groups Links
            >
            >
            >
            >
            >
          • J.D. Hoessle
            ... ...hehehe! I don t have a hammock YET; but, probably will after the New Years Eve hike. But..... I just *have to* comment on this thread: If the tree or
            Message 5 of 16 , Dec 7, 2004
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              --- In hammockcamping@yahoogroups.com, "Shane Steinkamp" <shane@t...>
              wrote:
              > > I took the physics too (actually got the degree).
              >
              > They knew about physics when you were in school?

              ...hehehe! I don't have a hammock YET; but, probably will after the
              New Years Eve hike. But..... I just *have to* comment on this thread:

              If the tree or trees are rotten OR if the knots are not tied correctly
              OR if the rope breaks, what "angle" is now achieved?

              Is that 180 degrees - flat out...?

              Does one go thru 360 degrees to "flat out"...?

              And, on the subject of wives, mine thinks I am quote: "Crazier than
              the outhouse rat" to be going up Springer at this time of year.

              Happy Trails,

              J.D.
            • jwj32542
              ... much ... between ... Got it...duh. Should have figured that one out on my own! Still pretty surprised that the horizontal forces can be THAT high. I d
              Message 6 of 16 , Dec 7, 2004
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                --- In hammockcamping@yahoogroups.com, Ralph Oborn
                <Ralph.oborn@g...> wrote:
                > As a thought experiment to understand how the rope tension may be
                much
                > higher than the load imaging the empty hammock strung tightly
                between
                > two sturdy trees. The vertical load is almost zero, but the almost
                > horizontal tension may be hundreds of pounds.

                Got it...duh. Should have figured that one out on my own!

                Still pretty surprised that the horizontal forces can be THAT high.
                I'd guess that after stretch, it's pretty difficult to keep the
                angle below 10*, though...no 5000 lbs loads for me!

                Jeff
              • jwj32542
                ... tight, Hrm...
                Message 7 of 16 , Dec 7, 2004
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                  --- In hammockcamping@yahoogroups.com, "zippydooda"
                  <zippydooda@y...> wrote:

                  > And Ralph, speaking of wives, I was imagining hanging mine too
                  tight,

                  Hrm...
                • Dave Womble
                  ... ...snip.. And, on the subject of wives, mine thinks I am quote: Crazier than ... If the weather gets bad enough, you may feel the same way.
                  Message 8 of 16 , Dec 7, 2004
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                    --- In hammockcamping@yahoogroups.com, "J.D. Hoessle" <JD@H...> wrote:
                    ...snip..> And, on the subject of wives, mine thinks I am
                    quote: "Crazier than
                    > the outhouse rat" to be going up Springer at this time of year.
                    >
                    > Happy Trails,
                    >
                    > J.D.

                    If the weather gets bad enough, you may feel the same way. <grin>

                    Youngblood
                  • David Chinell
                    Here are the methods and metrics I use for hanging my Speer-type hammock. This is for fair weather. Pick trees that are 13 to 17 feet apart. (I mean my feet,
                    Message 9 of 16 , Dec 7, 2004
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                      Here are the methods and metrics I use for hanging my Speer-type hammock.
                      This is for fair weather.

                      Pick trees that are 13 to 17 feet apart. (I mean my feet, heel-to-toe.)

                      Tie tree ropes at eye level. Tie a ridgeline about six inches above that.

                      Tension the hammock ropes (while attaching them to the tree ropes) so that
                      the top edges of the hammock come roughly midway up my thighs. When sitting
                      in the hammock, with my thighs horizontal and my knees bent 90 degrees, my
                      feet should be flat on the ground.

                      The point here is that it's easier to get in and out of the hammock when it
                      acts like a chair.

                      Bear
                    • J.D. Hoessle
                      ...hehehe! Youngblood ... Are you the same person who was up there 11/28 & 11/29 of this year (JUST A FEW DAYS AGO...!!!) and had the run in with the
                      Message 10 of 16 , Dec 7, 2004
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                        ...hehehe!

                        "Youngblood"... Are you the same person who was up there 11/28 &
                        11/29 of this year (JUST A FEW DAYS AGO...!!!) and had the run in with
                        the bear...? Saw some postings on WhiteBlaze while looking for
                        directions from a "Youngblood" and "Glee" and "Magnet" a/k/a "Bear
                        Pinata". Bears should be hibernating now....<g>...!

                        --- In hammockcamping@yahoogroups.com, "Dave Womble" <dpwomble@y...>
                        wrote:
                        >
                        > --- In hammockcamping@yahoogroups.com, "J.D. Hoessle" <JD@H...> wrote:
                        > ...snip..> And, on the subject of wives, mine thinks I am
                        > quote: "Crazier than
                        > > the outhouse rat" to be going up Springer at this time of year.
                        > >
                        > > Happy Trails,
                        > >
                        > > J.D.
                        >
                        > If the weather gets bad enough, you may feel the same way. <grin>
                        >
                        > Youngblood
                      • Dave Womble
                        I m the same Youngblood on Whiteblaze, but I wasn t the one that had a runin with a bear at Springer. There was a thread where Magnet had a bear take his
                        Message 11 of 16 , Dec 7, 2004
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                          I'm the same Youngblood on Whiteblaze, but I wasn't the one that had
                          a runin with a bear at Springer. There was a thread where Magnet had
                          a bear take his backpack out from under his HH at Springer earlier
                          this year.

                          Youngblood

                          --- In hammockcamping@yahoogroups.com, "J.D. Hoessle" <JD@H...> wrote:
                          >
                          >
                          > ...hehehe!
                          >
                          > "Youngblood"... Are you the same person who was up there 11/28 &
                          > 11/29 of this year (JUST A FEW DAYS AGO...!!!) and had the run in
                          with
                          > the bear...? Saw some postings on WhiteBlaze while looking for
                          > directions from a "Youngblood" and "Glee" and "Magnet" a/k/a "Bear
                          > Pinata". Bears should be hibernating now....<g>...!
                          >
                          > --- In hammockcamping@yahoogroups.com, "Dave Womble" <dpwomble@y...>
                          > wrote:
                          > >
                          > > --- In hammockcamping@yahoogroups.com, "J.D. Hoessle" <JD@H...>
                          wrote:
                          > > ...snip..> And, on the subject of wives, mine thinks I am
                          > > quote: "Crazier than
                          > > > the outhouse rat" to be going up Springer at this time of year.
                          > > >
                          > > > Happy Trails,
                          > > >
                          > > > J.D.
                          > >
                          > > If the weather gets bad enough, you may feel the same way. <grin>
                          > >
                          > > Youngblood
                        • David Chinell
                          Bill: Yes. In driving rain I lower the ridgeline until it s even with (or below) the tree ropes. If it gets even worse, I can lower the sides more by bringing
                          Message 12 of 16 , Dec 7, 2004
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                            Bill:

                            Yes. In driving rain I lower the ridgeline until
                            it's even with (or below) the tree ropes.

                            If it gets even worse, I can lower the sides more
                            by bringing in the corner pegs. I might even
                            consider switching from a diagonal pitch to an
                            a-frame pitch.

                            Bear



                            -----Original Message-----
                            From: zippydooda [mailto:zippydooda@...]
                            Sent: Tuesday, December 07, 2004 12:28 PM
                            To: David Chinell
                            Subject: Re: [Hammock Camping] How tight? What
                            Angle?



                            Cool, thanks. I guess for bad weather you would
                            lower the tarp
                            ridgeline?

                            Bill in Houston
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