## Rope tension

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• Treehangers: I just got my HH and immediatly hung it up on two trees I planted just for this occation 11 years ago. I tried to follow the group advice and put
Message 1 of 5 , Dec 15, 2003
Treehangers:

I just got my HH and immediatly hung it up on two trees I planted
just for this occation 11 years ago.
I tried to follow the group advice and put the tree huggers at eye
level etc and cinch it up pretty tight.
The sag still had the hammock bottom (and mine) about a foot off the
ground. Not bad for a test.

So I started thinking about the tensions at various angles......

Assuming I weigh about 200 pounds and the weight is evenly
distributed between the two ends. Using the force diagram triangle.
Tension in the rope equals 1/2 my weight divided by the sine of the
angle below horizontal.

So if the rope angle is 15° the rope tension is 386 lbs.

1 ° 5729.9
5 ° 1147.4
10 ° 575.9
15 ° 386.4
20 ° 292.4
25 ° 236.6
30 ° 200.0
35 ° 174.3
40 ° 155.6
45 ° 141.4

As you approach a flat no sag condition, the tension approches
infinity.

Finally found a practical use for that high school trig.

The tighter the rope, the better the hang, but the more force on the
rope, knot and tree.

O great wizards of the woods.... What angles are you using for
utmost stability and comefort?

Ralph

PS If anyone would like a copy of the spreadsheet so they can
calculate their stress level, give me a holler.

PPS Risk: Now we can calculate what it would take to hang a
hammock in a snow cave.

PPPS Perhaps if the people who want to hang a hammock in their
rooms could also use this data? Seems to me a ceiling hang would be
easier than a wall mount.
• ... wrote: ... I d love a copy, but why not put it in the Files section of the group web site. That way you don t need to keep sending it.
Message 2 of 5 , Dec 15, 2003
--- In hammockcamping@yahoogroups.com, "polecatpop"
<polecatpop@y...> wrote:
...
> PS If anyone would like a copy of the spreadsheet so they can
> calculate their stress level, give me a holler.
>

I'd love a copy, but why not put it in the "Files" section of the
group web site. That way you don't need to keep sending it.

> PPPS Perhaps if the people who want to hang a hammock in their
> rooms could also use this data? Seems to me a ceiling hang would
> be easier than a wall mount.

Not following here? Easier to attache the eye bolts? Or easier on

Thanks for taking the time to run the numbers...

Shane "Mirage"...
• ... You guys got files? cool It s posted Thanks for the suggestion ... on ... I guess my thinking is a bit muddled. Rather than pulling the wall studs
Message 3 of 5 , Dec 15, 2003
--- In hammockcamping@yahoogroups.com, "Mirage" <web_dawg@y...>
wrote:
> --- In hammockcamping@yahoogroups.com, "polecatpop"
> <polecatpop@y...> wrote:
> ...
> > PS If anyone would like a copy of the spreadsheet so they can
> > calculate their stress level, give me a holler.
> >
>
> I'd love a copy, but why not put it in the "Files" section of the
> group web site. That way you don't need to keep sending it.

You guys got files? cool It's posted

Thanks for the suggestion

>
> > PPPS Perhaps if the people who want to hang a hammock in their
> > rooms could also use this data? Seems to me a ceiling hang would
> > be easier than a wall mount.
>
> Not following here? Easier to attache the eye bolts? Or easier
on
> the stud WRT stress loads?

I guess my thinking is a bit muddled.

Rather than pulling the wall studs in I am thinking of using the
ceiling joists as a compression member of a frame.

At tight angles (high tension) the forces get quite large.

But I'm just not sure what practical angles are in actual use?

Some things to discuss????

>
> Thanks for taking the time to run the numbers...
>
> Shane "Mirage"...
• Ralph, You may or may not be aware of this so pardon me if you already knew this. The Hennessy Hammock that you are using is fundamentaly different from the
Message 4 of 5 , Dec 15, 2003
Ralph,

You may or may not be aware of this so pardon me if you already knew
this. The Hennessy Hammock that you are using is fundamentaly
different from the Speer Hammock (and probable most others as well)
in that it incorporates an integral hammock ridgeline. This integral
hammock ridgeline sets the sag of the hammock and in practice makes
the sag of the hammock support lines a non-issue, except for the
loading and stress of the the hammock support lines and the hammock
ridgeline. I think the stretch in the nylon tree huggers on the HH
about 15 to 20 degrees (just my guess) unless you work real hard at
pulling the hammock taut (which is something you don't want to do).

With the Speer Hammock, the hammock sag is determined by the sag of
the hammock support lines so they directly effect the comfort, or sag
if you will, of the hammock.

Dave

--- In hammockcamping@yahoogroups.com, "polecatpop" <polecatpop@y...>
wrote:
> O great wizards of the woods.... What angles are you using for
> utmost stability and comefort?
>
> Ralph
• What a great group Yes, These are dead weight static values. They should be considered a starting value for any real safety factors etc. Obviously Ed and Tom
Message 5 of 5 , Dec 15, 2003
What a great group

Yes, These are dead weight static values. They should be considered
a starting value for any real safety factors etc. Obviously Ed and
Tom with their respective geniuses have already taken into account
I thought it was just a way to see what stress we were putting on
the tree.

If I understand Daves point, it doesn't matter how tight I hang my
HH, the required sag is set by the ridge line. As long as I get the
ridge line tight, but not to tight, all should be well.

What a group, thanks for all the input

Ralph

--- In hammockcamping@yahoogroups.com, "Dave Womble" <dpwomble@y...>
wrote:
> Ralph,
>
> You may or may not be aware of this so pardon me if you already
knew
> this. The Hennessy Hammock that you are using is fundamentaly
> different from the Speer Hammock (and probable most others as
well)
> in that it incorporates an integral hammock ridgeline. This
integral
> hammock ridgeline sets the sag of the hammock and in practice
makes
> the sag of the hammock support lines a non-issue, except for the
> loading and stress of the the hammock support lines and the
hammock
> ridgeline. I think the stretch in the nylon tree huggers on the
HH
over
> about 15 to 20 degrees (just my guess) unless you work real hard
at
> pulling the hammock taut (which is something you don't want to do).
>
> With the Speer Hammock, the hammock sag is determined by the sag
of
> the hammock support lines so they directly effect the comfort, or
sag
> if you will, of the hammock.
>
> Dave
>
> --- In hammockcamping@yahoogroups.com, "polecatpop"
<polecatpop@y...>
> wrote:
> > O great wizards of the woods.... What angles are you using for
> > utmost stability and comefort?
> >
> > Ralph
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