# Thread: How much force is on a dutch clip??

1. ## How much force is on a dutch clip??

Hey guys, i have been searching round the forum and cant quite find the actual numbers involved in dutch clips. I just finished making my own dutch clips out of 3/8 aluminum, and want to know how much actual force is put on the for a person of and average male weight: say, 200lbs. Does anyone know??? can someone shed any light on this??
Thanks,
Dan

2. You might enjoy this thread over at Whiteblaze considering the lateral forces a hammock places on the lateral supports whether they be a wall in a house, a tree, or a dutch clip or biner

http://www.whiteblaze.net/forum/show...highlight=math

3. At a 30 degree sag angle, the load on EACH suspension line us equal to the weight in the hammock. 200# in the hammock means 200# tension on each line.

It would seem to be half of the weight but trigonometry says otherwise. There are several threads on hammock loading on suspension lines at different angles.

4. Hmm... that's tricky. Because of the angles of the strap going around the tree the forces on the clip really are a combination of bending and tension. The bigger the tree, the less the bending plays a role... but by then you'd probably have a lot of force being taken up by friction anyway...

So assuming you had an infinitely large diameter tree with frictionless bark, the tension pulling the clip apart would be 100#. Did that help? Didn't think so.

5. Originally Posted by matto
So assuming you had an infinitely large diameter tree with frictionless bark, the tension pulling the clip apart would be 100#. Did that help? Didn't think so.
That is wrong. to have friction, you must have displacement or movement.

6. Originally Posted by dandeman
That is wrong. to have friction, you must have displacement or movement.
No, there's usually quite a bit of static friction on a tree strap.

7. Originally Posted by matto
No, there's usually quite a bit of static friction on a tree strap.
Agreed. That said, its not that simple and really depends on how you have the webbing around the tree. Say you were to wrap the webbing a few times around the tree - it is conceivable that you could have almost zero force on the dutch clip. It would simply be holding end of the webbing to the main part of the line. On the other extreme (in a poorly hung hammock), you could have the dutch clip off to the side on the tree so that the main tension line of the hammock has to pass through the dutch clip and make a sharp bend before wrapping around the tree. In this case, the dutch clip would be bearing almost the full tension load on the webbing.

Worst case is that the dutch clip is bearing whatever the full tension load on the webbing is (which, as stated before, is dependent on the weight and geometry of the hang).

8. And according to how you place the hardware at the tree, the force generated by the angle could be increased, just as you multiple your effective force on a rope by using a pulley.

This (and all the complexities that mean no "one size fits all" answer) is one reason that professional riggers often use a rule of thumb when human safety is involved, of 10-to-1. A 200 lb hiker needs every element of his support system to be rated to 2,000 lbs.

But that's only if you want to be safe.

For what it's worth, on occasion I've avoided knots and hardware altogether and I've hung with nothing more than wrapping my rope around the tree. The friction is tremendous (but not good for the tree).

Rain Man

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9. Originally Posted by flyboy
Agreed. That said, its not that simple and really depends on how you have the webbing around the tree. Say you were to wrap the webbing a few times around the tree - it is conceivable that you could have almost zero force on the dutch clip. ..........
I am definitely no expert on this. However, I observe the above all of the time. I often vary the amount of rope/webbing I wrap around the ~ 2" diameter Vario hammock stand so I do not always hve wear and tear on the same spot. When I wrap a bunch of times and clip the biner, there appears to be almost no force on the biner. It mostly just keeps things from unwinding.

Same with the HH fig 8 hitch. After a few fig eights, I usually put in a couple of 1/2 hitches to keep it from unwinding. ( Or, if there was a biner or dutch clip, I could just clip) But I have noticed that if I pull really hard on the rope, it does not unwind even without the 1/2 hitches. There is virtually no force on the 1/2 hitches, and would be none on a dutch clip if that was used instead. More evidence is that, after hours of hanging, the 1/2 hitches are never tight like a weighted knot would be.

So my guess ( WAG ) is that the force on the biner or clip can vary greatly depending on how the webbing is wrapped around the tree. plus various angles involved, which also vary. Unlike the force on the rope between the hammock and tree, which I suppose will vary only with the angles and weight of hanger.

But, caveat: I am an ignoramus on the actual science and math re: this subject.

10. I'm 250lbs at 20deg angle I put about 140lbs side load on the strap. so at my weight the clip should hold 240lbs with a safety factor of 2 the clip it should hold 440lbs without break.