## 12201Re: hammock ridgeline stresses

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• Jan 2, 2006
Greg,

I was talking about selecting a rope for the hammock suspension line,
or the line you attach to the tree. It is different than the
ridgeline. I was also concerned about the hammock suspension line being
more than strong enough for a range of conditions and my feeling is
that a structural ridgeline can greatly add to that range of conditions-
- especially if one initially sets the hammock suspension lines taut,
stretches the hammock system out by getting in or on it and then
retensions the hammock suspension lines.

It you look at this diagram, http://tinyurl.com/b8jl8 , it is one I put
together in an attempt to show what is going on. I hope I got it
right, it uses vectors and when I went to school it was how one went
about defining forces in complex structures. It is based on Neutons
laws of motion, which have stood the test of time for hundreds of years
without exception. Hammocks have a degree of complexity as far as
force calculations go and a structural ridgeline certainly adds to
that. It is customary to use vectors to help simplify the mathematic
models.

But, like you mention one can set up simple physics experiments to
either prove or disprove the results and I think that is great thing to
do if one is so inclinded, I did myself to convince myself of the
charts I found in an article I read that was written by cave rescuers.
That article described the forces on the suspension lines but I don't
recall it describing the forces on a structural ridgeline itself. This
is a link to a pdf file for part 3 of that article:
analysis starts of page 6 of 61.

Dave

--- In hammockcamping@yahoogroups.com, Greg Welker <gdwelker@v...>
wrote:
>
> Dave, I'm familiar with the Hennessey - it's one of the ones I
> own. You said:
>
> >but my guess is worse case would be 3 times as much, but I would
> >certainly plan on at least twice as much.
>
> Remember the guy who did the cutting of the hennessy ridgeline and
> inserted the carabiner? If you did that, you could easily insert
> something like a fish weight hanging scale and determine the strain
> in the ridgeline. Testing the strain in the ridgeline I can't see
> that it holds a significant portion of the force vector that is on
> the hanging ropes, especially not to the point that you need to