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

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• ... 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 4:52 PM
--- 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
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
• 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 5:33 PM
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
• ... 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 5:47 PM
--- 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.

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
• 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 7:48 PM
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
>
>
>
>
>
>
>
>
>
>
• ... ...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 5:42 AM
--- 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.
• ... 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 5:48 AM
--- 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
• ... tight, Hrm...
Message 7 of 16 , Dec 7 5:51 AM
--- In hammockcamping@yahoogroups.com, "zippydooda"
<zippydooda@y...> wrote:

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

Hrm...
• ... ...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 6:23 AM
--- 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
• 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 6:53 AM
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
• ...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 7:08 AM
...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
• 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 10:19 AM
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
• 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 10:26 AM
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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