Strength of rigging parts

[warbonnetguy]

well, theoretically yes, but from the messing around i've done, no matter how tight you pull the suspension it ends up being no less than 25 deg after it's weighted. all that "drop" you get from entering the hammock after a tight pull changes the suspension angle quite a bit as the hammock lowers. pulling it tight and getting in does put alot more force on the rl though, but the suspension lines still end up at around 25 deg after it's all said and done and the forces for 25 deg aren't THAT much more than they are for 30

[Youngblood]

Ramblinrev is correct and Brandon, not everyone sets up there hammock the same way. I suspect there are still some with structural ridgelines that tie off lower to the trees, re-tighten the suspension after the initial drop when they get in, and end up with much higher tensioning than their body weight on each side. These quick adjusting suspension components that are located near the hammock knots encourage that. With those it is easier to tighten the suspension lines instead of raising the tie off height if the hammock is too low to the ground.

[TonyF]

Great discussion

[Doctari]

Keeping in mind the "angle of attack" (or attach[ment]) it's amazing what you can hang from if the angle is right. I have hung from 2 OLD vertical 2 x 4s inside a shelter with my suspension straps at almost vertical, there is no way it would have held my 220 Lbs if I was any where near horizontal, but I spent a nice night with no slipping or unusual noises from the 2x4s.

And, I HAVE hung from 2 (one at each end) key ring biners rated at 150 lbs each, at least for a few nights. My current set up, the weakest link being my spectra cord ridgeline / hammock suspension, will support around 1200 Lbs.

[warbonnetguy]

Ramblinrev is correct and Brandon, not everyone sets up there hammock the same way. I suspect there are still some with structural ridgelines that tie off lower to the trees, re-tighten the suspension after the initial drop when they get in, and end up with much higher tensioning than their body weight on each side.

maybe, but how much more? sounds like alot who do that also tie their hammock higher up on the trees to begin with too, their suspension may be initially horizontal, but it's alot higher up on the tree to account for the inital drop they know they will experience, they're climbing up into them with rl's shoulder height or above, but once weighted the rl is "much" lower. i didn't think about successive re-tightening, but i also wonder how much lower an angle you could really get.

ok, maybe i shouldn't have said "not much more than bodyweight". from what i understand, less than a 30 deg angle does indeed put more than bodyweight on the supports and less than 30 deg is definately possible, but it's no where near 1200#, i'd be surprised if any here are putting over 500# on it.

when i was messing around with the lowest angle i could achieve, i never weighted, and then tightened again, so i'll have to do that next time i'm in the woods, but i did use a short span and used amsteel and a trucker's hitch. i'd be surprised if you could get to 20 degrees though, lowest i could get was about 25.

according to the "hitrchcraft for hammocks" thread, a 20 degree suspension angle puts 146% of bodyweight on each support, so 250 # person would put 365 on the support. it doesn't give a number for a 25 deg angle, so i overguessed? it at 130% based on the given figures for 20 and 30 deg. so assuming 25 deg is close to 130% 250# at a 25 deg angle would only be 325#, only 75 or so pounds more than bodyweight.

a 300# person and 20/25 deg angle would be 438/390. and i would be really surprised if someone weighing 300# could keep their suspension at 20 deg after they got in, even if they did get out and re-tighten. the 2 knots you tie at each end would let out at least an inch total as they tighten from weight. if you use webbing/cinch buckles, the webbing would stretch. thinking about it, you could probably get it the tightest with dyneema webbing and cinch buckles that you got out an re-tightened a few times, or maybe the hitchcraft device with amsteel blue and a 3:1.

i realize those numbers are static weight only so you'd have to figure for some bounceing, but nobody really bounces hard in their hammock. i think it would be really hard to go over 500# force, but it would be really interesting to see what some of you guys who have 2 short-span trees in your backyard can measure as the lowest angle you can get? and what does it take to get that angle?

[Youngblood]

maybe, but how much more? sounds like alot who do that also tie their hammock higher up on the trees to begin with too, their suspension may be initially horizontal, but it's alot higher up on the tree to account for the inital drop they know they will experience, they're climbing up into them with rl's shoulder height or above, but once weighted the rl is "much" lower. i didn't think about successive re-tightening, but i also wonder how much lower an angle you could really get.

...

The successive re-tightening makes it hard to figure how much tension you can put on things but it can get pretty high if you get carried away with it. That is the whole point of the hang 'em high campaign. If you hang 'em high you don't need to do that but if you hang them low for a specific span distance and have the easy to adjust suspension length ring buckles, cinches, etc that are close to the hammock knots-- the temptation is there to just re-tighten to get the hammock at the height you want. If you have to go all the way to the tree to make an adjustment and it is just as easy to raise the tie-off height, then there is a better chance of someone raising the tie off height instead of just re-tightening to raise the hammock height.

[Dutch]

Before I was enlighted about the proper angle I would get my suspension about as tight as I could. I think I did it that way because I was still using the HH fly on the suspension. The more the angle the more the seperation of the hammock and the fly. The stock fly doesn't give much room for error. Now that I use adult size tarps that get tied to the trees i don't need to have a completely horizonal sispension. I do have trouble getting 30 degrees when the trees are too far apart. I bet alot of HH users taking their hammocks right out of the bag are overtightening. I don't remember anything in the derections aboutusing an angle.

[Ramblinrev]

I don't remember anything in the derections aboutusing an angle.

That's because there isn't anything. The sack directions make it sound like you should crank that bugger down as tight as it can go. Big mistake.

I hang mine (explorer UL) just about eye height using a ring buckle system. Then I sit in it to tension it. If it drops too far for my liking I will tighten the suspension to reach height, but not worry about tension I usually end up with a lightly tension ridgeline to start and a moderate drop when I get in. But all in all, I no longer feel like I have to use to the tight webbing (ropes) to stay off the ground. That's a function of hanging height.

[warbonnetguy]

The successive re-tightening makes it hard to figure how much tension you can put on things but it can get pretty high if you get carried away with it.

dave,
i don't understand that, from what i understood, you can just measure the angle of the weighted suspension in relation to the angle of the rl, and no matter how many tries it took to get it there, that angle would tell you what kind of forces you're looking at.

my point is that everytime someone tightens the crap out of their suspension, they get "alot" of drop and that drop increases the suspension angle by a ton. the "re-tightening" thing would have to work so well that it got rid of almost all the inital drop if it were going to hold a low angle after weighting and i don't think that's happening. i say 20 deg is not possible, but even if 20 is the min angle, it's still only 146% of bodyweight, which isn't that much.

definately hang at the appropriate angle to begin with to avoid "drop" and over tensioning the rl. there's no real advantage to pulling it horizontal unless you do it because you can't get the straps any higher on your trees (like if they're very far apart), but it's gonna "drop" the hammock bottom and it's gonna drop the suspension to a reasonable angle as well.

[Youngblood]

dave,
i don't understand that, from what i understood, you can just measure the angle of the weighted suspension in relation to the angle of the rl, and no matter how many tries it took to get it there, that angle would tell you what kind of forces you're looking at.

It is true that the angle will tell you the forces that are on the weighted suspension at that instant. It won't tell you the forces that might have been on it before that instant-- the forces that caused something to give, stretch, or reposition to relieve what might have been a higher force when you started with a near-zero suspension sag angle.

It isn't difficult to go through the geometry and force calculations to see how much stretch and drop you get for particular sag angles when you started from a near-zero sag angle (this assumes it is all stretch of the suspension line), I have done that before. For instance, for a HH ULB at a 12 foot span, all it takes is 0.8 inch stretch on each suspension line to get the hammock to drop 5.5 inches and you end up with a 14.5 degree suspension angle that represents 2x the users weight on each suspension line. At a 20 foot span, it takes a 2.4 inch stretch on each suspension line to get an 18 inch drop with that 14.4 degree suspension sag angle.

I would think this is more of an issue with longer spans because the repositioning aspect of the suspension attachment at the trees becomes less of a factor. It is reasonable to expect that certain attachment methods at the trees might limit the minimum suspension sag angle more than other attachment methods. When you have webbing with carabiners, multi-wrap technique, webbing passing through webbing loop and suspension rope attached to only one of the webbing loops, tree huggers where the suspension rope attaches to both webbing loops, a non-cinching loop with a slippery bow line knot, etc, you have a wide variety of attachment methods and they may not all perform the same way where this issue is concerned.

my point is that everytime someone tightens the crap out of their suspension, they get "alot" of drop and that drop increases the suspension angle by a ton. the "re-tightening" thing would have to work so well that it got rid of almost all the inital drop if it were going to hold a low angle after weighting and i don't think that's happening. i say 20 deg is not possible, but even if 20 is the min angle, it's still only 146% of bodyweight, which isn't that much.

I think to say that 20 deg is not possible is foolish if it is interpreted as an absolute statement and you really mean that is your best guess based on what you have noticed. Someone can always re-tighten things and do it in a 'manly' way. I don't think we know what the limit is. Folks can use a truckers hitch to gain mechanical advantage or other means to get who knows how much force on the suspension lines.

Re-tightening repeatedly to take out looseness after it has stretched can get a little scary when you talk about possible failures just by the very nature of why things might be stretching-- that is almost like a ratcheting effect to slowly raise the hammock. With some of the suspension lines, stretching is what it does before it fails and if you keep re-tightening and causing it to stretch more and more, well even though I did that in the past before I realized what was going on with forces and got by with it, it doesn't sound good to me. People need to be careful in what they do and how they go about adjusting their hammock setups.