Does wrapping a tree strap twice equal using a wider strap?

[zukiguy]

Maybe an experiment is in order. Rig up a model suspension and put the single wrap tree hugger setup around your upper thigh. Have an assistant add some weights until you start feeling some significant discomfort. Switch out the suspension setup and repeat. Which one "hurts" more? If it hurts your leg more it will likely hurt the tree more too.....

[tundracamper]

We are comparing a hurting strap wrapped around an arm or leg to a hammock strap "hurting" a tree? As long as there is no physical damage to the bark, is it really that big of a deal? Trees regrow, right? I have lots of furniture in my house and an entire house made out of wood. Please tell me your not about to start an organization for the ethical treatment of trees

[Firetruck]

We are comparing a hurting strap wrapped around an arm or leg to a hammock strap "hurting" a tree? As long as there is no physical damage to the bark, is it really that big of a deal? Trees regrow, right? I have lots of furniture in my house and an entire house made out of wood. Please tell me your not about to start an organization for the ethical treatment of trees

I agree that comparing a human limb to a tree does not prove anything. Soft tissue vs wood? To the second part of your post, I don't think anyone is starting a "tree hugger" organization. However I do believe we should try to take care of what's been entrusted to us. If not "they" may stop us from using our woods for our style of camping. No different than the use of any other part of public land. Leave no trace and come back and enjoy again.

To the OP... The subject line says "is it the same as?". Well just from my simple mind I read the question as does it spread the load across the bark so as not to damage it. To that I would say...yes.

[gmcttr]

...The finger pulling string analogy makes me realize part of what lessens the pain in that scenario is the ability to layer the string over itself. String-on-string where the entry/exit string is concerned really cuts down on how much the leading string cuts into your fingers when it is loaded. For that reason I'm inclined to think if you layered the leading strap over other layers of lower strap you might provide considerably more protection to the tree overall.

As you surmised, it is the padding of many wraps piled up that is making the different and not a reduction of localized forces from the string pressing into the piled up string at the entry/exit wraps. Also, the possibility of the string slipping and "sawing" into the skin is removed (press down with a knife and nothing happens, slide it every so slightly and you are cut).

I suppose we need Mythbusters and their strain gauges to do the appropriate testing. Where's the engineers with their calculations when I need them?

[gmcttr]

Testing on "soft tissue" for a visual reference.

5/8" mule tape with an 8.5 lb weight and soft foam. My soft tissue test "tree"...

IMG_5121 (Medium).JPG

Single wrap...

IMG_5123 (Medium).JPG IMG_5126 (Medium).JPG

Double wrap showing little pressure on the wrapped section...

IMG_5134 (Medium).JPG IMG_5132 (Medium) noted.jpg

Side by side. I'm seeing the same indentation at the 'center back' for both the single and double wrap...

Strap composite.jpg

[DanglingModifier]

I agree that comparing a human limb to a tree does not prove anything. Soft tissue vs wood?

In that scenario you are the instrument for measurement. If something feels like it digs in to you more, then it would dig in to a tree more as well. Exactly how much "more" might not really matter for the purposes of this discussion.

[DanglingModifier]

As you surmised, it is the padding of many wraps piled up that is making the different and not a reduction of localized forces from the string pressing into the piled up string at the entry/exit wraps. Also, the possibility of the string slipping and "sawing" into the skin is removed (press down with a knife and nothing happens, slide it every so slightly and you are cut).

I suppose we need Mythbusters and their strain gauges to do the appropriate testing. Where's the engineers with their calculations when I need them?

I surmised that the padding of wraps under wraps makes a difference, but I'm unconvinced it makes the entire difference.

The inner wrapped section in your photos shows less pressure than the leg, but it stills shows some pressure. I'd be curious to see if the indent on the leading legs was measurably different if you had a couple more wraps. We're in agreement that 2 wraps x .5" likely won't equal 1 wrap x 1", but any indentation on the second (or third, fourth) wrap should be an indication of a distributed load. I'm guessing one vs two isn't enough to see it by naked eye when using soft foam. Heck, it's possible that the indent would look the same by eye for either 10lb or 5lb of force. Maybe it will take a few more wraps and a harder foam to see the difference, if it exists.

What I liked about my experiment is that I didn't need to rely on the naked eye to measure the indent on my forearm. When something is very uncomfortable only very minute adjustments are required to make the situation noticeably more uncomfortable or noticeably less. Several more wraps caused considerably less discomfort. I just did it again and confirmed that was the case regardless of whether I rode over lower layers of wraps or not with the leading legs.

I'm still of the opinion that multiple non-overlapping wraps lessens the overall PSI, even if it isn't evenly distributed over the surface of the tree. Further, we appear to agree that wraps that do overlap should also lessen the PSI. Ergo, I still conclude a double wrap (especially if done correctly with some overlap), reduces the compression on the tree by some amount. I'm still sticking with 1" straps though.

[cougarmeat]

Aside from the force, the double rap makes the strap less likely to slide down the tree. I don't think I'd ever use a single "once around" unless somewhere in the path some part of a branch would keep the strap from sliding down.

[gmcttr]

Aside from the force, the double rap makes the strap less likely to slide down the tree. I don't think I'd ever use a single "once around" unless somewhere in the path some part of a branch would keep the strap from sliding down.

Our "once around" example is only an 'easier to discuss' stand-in for the standard "once around the tree and connected back to itself" setup and avoids having to think about the uneven forces from one side to the other in the normal setup.

[gmcttr]

...I'm still of the opinion that multiple non-overlapping wraps lessens the overall PSI, even if it isn't evenly distributed over the surface of the tree. Further, we appear to agree that wraps that do overlap should also lessen the PSI. Ergo, I still conclude a double wrap (especially if done correctly with some overlap), reduces the compression on the tree by some amount. I'm still sticking with 1" straps though.

Whether the strap is once around or twice around (or 20 times around), the force pushing the tree toward the hammock remains the same. If this was not true, we could stick a 2x2 in the ground just far enough for it to stand on it's own and wrap the strap around it multiple times until weight in the hammock had no effect on it and we would have the holy grail of hammock stands.

All of the force pushing the tree toward the hammock is imparted from the first wrap to the back ~179° of the tree. This is the force we are attempting to spread over a wider area in order to reduce the PSI to this area of the tree. Any force applied by subsequent wraps is offset by being applied to all sides of the tree at the same time.

So what force is the second wrap reducing? We know it's there because if we stick our fingers under this wrap it is tight.

The force being distributed by the second wrap is the tension in the strap which is perpendicular to the surface of the tree.

Here is my poor attempt to depict this visually. Large red arrows indicate greater force than small red arrows.

Tension in Strap.jpg

Another way to think about the strap tension being distributed, is to think of the strap coming from the hammock being very tight, but if you wrap it around the tree multiple times it will not have any tension left in it and a simple tuck to hold it up is all the connection added to support the hammock.

...What I liked about my experiment is that I didn't need to rely on the naked eye to measure the indent on my forearm. When something is very uncomfortable only very minute adjustments are required to make the situation noticeably more uncomfortable or noticeably less. Several more wraps caused considerably less discomfort. I just did it again and confirmed that was the case regardless of whether I rode over lower layers of wraps or not with the leading legs....

All I can say (and with all due respect) is that the mind can be a very deceptive thing and often "confirms" what we believe to be true. In this case, it appears to be happening to one or the other of us.

By the way, the answer to my question about the sketch in post #6 is 400 lbs.