Question: Has anyone measured their hammock purchased from the store?

[exup]

500lbs? That seems a bit much for a weight rating.

What made you want to start making hammocks?

[Bubba]

500lbs? That seems a bit much for a weight rating.

What made you want to start making hammocks?

ENO's rate theirs for 400lbs so I suppose if they want to market their material as being superior, then they should at least have the same if not stronger rating than their competitors.

Their business model is laid out in their Kickstarter video and in the other Kammock related threads.


Based on the hammock physics, I think each biner should at the very least match the weight rating of the hammock.


.

[TehNoff]

Based on the hammock physics, I think each biner should at the very least match the weight rating of the hammock.

Yeah, seriously. Though I may be new here and new to hammocks I've already made the personal decision that the weakest point in my whole set up will be the hammock itself.


As far as the 'biners ratings goes: because of the way the load is pulled on the suspension "adding" the weight ratings doesn't really make sense. They load isn't split between the two ends, rather it's felt equally and in full on both ends. Or that's how I understand it.

[OfftheGround]

Thanks for making some valid points about the biners. Just in case there was any confusion... the biners are going to come pre-attached to the gathered rope ends of the Kammok Roo. Also, each lot of carabiners are randomly tested to make sure that the break strength of each biner is consistently above 800+lbs. We have/do/will constantly be testing our carabiners for consistency and safety. I appreciate the feedback and suggestions - all will be taken into account and considered!

[OfftheGround]

This one's from Sgt Rock:

Hi dejoha! Great info graphic...very helpful. If I am understanding this correctly, this is showing that the force on Force2L & Force 2R is the weight carried in the hammock divided by 2. Is this correct? If so, wouldn't this mean that each biner would need to be rated to hold 1/2 of the weight? Similarly, wouldn't each suspension strap need to be rated for 1/2 of the rating of the hammock itself?

All of our products are capable/tested to carry more weight than our "max weight limits". It wouldn't be wise or prudent to rate these products right at their max weight limits 1) for liability purposes and 2) the products loose other functionality (ie. comfort) at higher weight limits.

[dejoha]

This one is simpler, to the point, and I think makes more sense (this was the one I was looking for originally). From Jack of Jacks'R'Better.

As I understand the physics, the force is not divided in half. For example, if the weight in the hammock is 200 lbs and the suspension is at 30 degrees, than the tensile force on each rope is about 200 lbs, not 100 lbs on each rope. As the angle changes and becomes closer to horizontal, the force increases exponentially.

I've seen this in practice on my steel hammock stand in my back yard. When I hang my hammock at 30 degrees, the steel flexes inward slightly. When I pull the hammock more horizontal and get in, the steel flexes even more. It's amazing to watch. I know I could bend that steel frame if I get closer to horizontal (either that, or my hammock or suspension would fail first).

[TehNoff]

So, "S" is what the tree feels and "T" is what our webbing, slings, 'biners, and rap rings feel?

[dejoha]

So, "S" is what the tree feels and "T" is what our webbing, slings, 'biners, and rap rings feel?

Yes.

S = Shear force. The force pulling the trees (support anchors) inward.

T = Tensile force. The force on the webbing, suspension lines, hammock, and any hardware used along the way.


I know there are some folks on the forum who have heavy-duty scales that can be placed inline with the suspension. I'd like to see the real-world application, maybe in a video, if someone wants to do it--to see the difference in tensile force as the angle is changed.

[Sparrow]

Both sides of the argument are correct.

The weight of the load in the hammock is divided in two AND the force exerted on each end of the suspension is equal to the total hammock load.


The "tensile force" felt by each strap is = [("weight of the hammock load"/2) + ("horizontal force")]


Each suspension end will always carry 1/2 of the weight load. This is the minimum force which could be exerted on one side of the hammock suspension and is achieved when the suspension is hanging vertically.

The only variable in the equation is the angle of the hang which increases the tensile force on the suspension exponentially as the suspension approaches the horizontal.

At the magic 30* the horizontal force being exerted on he suspension is equal to 1/2 the load weight.

1/2 + 1/2 = 1

Therefore, at 30* the force felt by each suspension side is equal to the total hammock load weight.