Suspension loading

**Charliev** · 04-06-2014, 15:56

Hi thought this would be interesting so i hooked up some scales to suspension system and checked weights at various hang angles. I used my eno with atlas straps for ease of hooking up scales. I hooked scales to strap loops and carabiner on hammock. This was with hammock level. Position in hammock did not seem to make much difference. I used inclinometer on hammock while sitting on it to check angles. Angles are not absolute but as close as i could get with limited adjustment of atlas straps. Straps are fastened to fixed anchors so could not slide up and down trees for precise angles. With hammock flat as could get my body weight +41%
At 20* body weight +27%
30* body weight +.05%
45* body weight -15%
Dynamic at thirty * body weight +80% and i did some pretty serious bouncing around to get it that high.
The atlas straps are rated at 200 lbs per strap so a 200 lb person hanging at 30* would be over limit. I don't think too much of the straps. Very heavy, cumbersome and not very strong. I bought before i thought or knew. Understand these are not absolute values but pretty representative of results of my efforts.

**gmcttr** · 04-06-2014, 16:29

Very interesting. I never had a way to check while I was in the hammock.

Some time back I made this post to illustrate that the angle does change the forces.

Here's a simulator you can play with as well...http://tagsafety.com/library6.aspx

**Mountnman** · 04-06-2014, 16:38

Thanks for the data. The ultimate hang calculator app for smartphones is a very hand tool

**Charliev** · 04-06-2014, 17:34

Sorry i did not search to see that this had been done. Interesting chart. About what i got with scales. I did read about the higher readings at shallow hangs.

**Bubba** · 04-06-2014, 19:03

The rating on the Atlas straps is probably a safe working load. I suspect a larger company like ENO would have straps that would actually fail at much higher than 200lbs. I could be wrong though.

**CopperJL** · 04-06-2014, 20:07

If the straps are rated at 200lbs each, then wouldn't it have to be +100% to reach the load limit? So for example, at 20*, you're at 127lbs per strap, still 146lbs to get to limit total.

Unless I'm totally missing something....

**Countrybois** · 04-06-2014, 20:52

If you weigh 100lbs

**Charliev** · 04-07-2014, 08:10

Originally Posted by CopperJL

If the straps are rated at 200lbs each, then wouldn't it have to be +100% to reach the load limit? So for example, at 20*, you're at 127lbs per strap, still 146lbs to get to limit total.

Unless I'm totally missing something....

If you weigh 200 lbs then the weight on each strap would be 294 lbs according to hang calculator. That is above what i measured but my measurements were still above the 200 strap limit.

**Charliev** · 04-07-2014, 16:30

Originally Posted by Bubba

The rating on the Atlas straps is probably a safe working load. I suspect a larger company like ENO would have straps that would actually fail at much higher than 200lbs. I could be wrong though.

I don't know but what it says on the straps is max load 200 lbs per strap.

**nothermark** · 04-07-2014, 20:51

You have to factor in the hang angle. The flatter (tighter) the higher the stress at the tree. At 30 deg hang angle the tension on each rope = the weight of the load in the hammock. At a 0 deg angle the force approaches infinity. At 90 deg the load splits in half. Run one of the calculator programs and you can see the forces change with angle.

The slap straps are probably rated with a safety factor of between 5 and 10. That is the range I usually see for human suspension part safety factors.

If you read a lot here you will find some of the gram centric folks use the "if it did not break it's good enough" safety factor. They are the one's who really scare me.