Is this a safe/legitimate rigging method?

rfwoody

Treehouser
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North Mississippi
Hello All.

Is this a safe and legitimate way to tie an anchor to the base of a tree for horizontal rigging/pulling?

The standard method seems to be to use an eye type sling, but I don't have one and I wanted to be able to tie a good anchor using just rope.

Is this a safe, legitimate way of constructing a rigging anchor?
(picture is a little off... doubled basket hitch goes through ALL (e.g.) 3 wraps of rope around trunk.

Three_Wrap_Rigging_Anchor.jpg
 
The main thing, I would think, is to make sure your body is out of the line of fire if any component of the system were to break. Other than that, I think your setup is worth a try. I'm an amateur, though, full disclosure.

Tim
 
I think it would be better to add a metal connector between the rope wraps and the nylon sling. If there is enough movement , the textile to textile might wear or melt.
 
Why not just tie a bowline in the end that you're clipping the carabiner to and cow hitch or timber hitch the tail?
 
Forget the nylon sling. If you have enough 1/2" line to go around the tree 4 times, just use it doubled. Find the middle and clip that to the carabiner, then use the doubled line to make a timber hitch onto the tree.
 
Looks ok. I bought a 30 ft piece of 3/4 tenex to go around the base of trees too large for my slings. I tie a bowline and it will hold anything I need. As DMC said just tie a loop in a piece of 1/2" and loop it around the tree. That's a 7,000 lb line doubled. Should be more that you'll ever need.

I believe I heard somewhere that the timber hitch doesn't like to be loaded in one certain direction. Can't remember which. Either straight out or back towards the loop. I think Patrick had a video about it on Educatedclimber. But I've never had it come loose on me.
 
A timber hitch needs to be loaded into the formed loop so that the hitch constricts onto whatever it is tied to.
 
Kinda been playing with drawing of for Clock Hitch thread over yonder,
why that pull is wrong, and this is similar pull geometry.
i think can do similar to what is shown tho..
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A>w/o sling
B> NOT pull across tree wraps, but rather allow rope to make sharp teepee or beak service to pulley
>>Leave knot as splice on front of trunk so no direct hits and easy spot checking!
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Some version of the mountain / rescue wrap 2, pull 1 (has different names/counts)with sharp teepee/beak so pull goes down length of line and not across line of support.
>>can do wrap 6 pull 5 whatever
>>Want pull to be down column of line properly as much as possible
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w3p2.jpg

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hit to pulley is max 2xLoad if straight legs, less if legs spread apart in/out of pulley.
Support to pulley is exact same math.
At 0degrees spread load/support is 2x line tension
At 60 degrees spread, each leg is deflected 30 degrees from PURE INLINE
therefore for 1000# tension on 2 legs 30degrees ea. would be 2 x 866 (2 x 1000 x .866 cosine of 30 =1732) of load pull on pulley or support to pulley from other side of equation is all the same
If pulling with 2-1 pulley spread 60 with 1000# pull would get 1732, not 2000, just the same
30 very acceptable support spread as the cosine of 15(each leg deflected 15 from center= 30) is .965 almost full force PURE INLINE cosine of 1 multiplier
all rest of cosines are less than 1 , i use as a multiplier% of line tension
Thus i call cosine columnSine or working to my cos(cause) as menomic
>>forces down the roman column of line or beam
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Great columns held the temple roof strong inline down their length,
>>Samson defeated with equal/opposite force across length of columns like pic shows being done to (your
pictured) wraps on tree,wrenching close to Zer0 cosine
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I think virtually all knot strength is in legs of support
>>and the geometry of those legs
>>expect same in rigid supports of wood or metal
>>rope is just another support device>>only immediately malleable unloaded (also can make rolling lever)
 
  • Thread Starter Thread Starter
  • #15
Thanks all for the good ideas to digest.

TreeSpyder, I really want to understand what you are saying and I plan to read your post through slowly and carefully tomorrow. (and the rest of the replys again tomorrow)
..... you mentioned the Clock Hitch... after I posted the question I was re-reading Jeff Jepson's "Knots at Work" book and it seems the Clock Hitch pretty much answers to what I was trying to do... only much better no doubt.

But the idea of making my own sling out of a long piece of rope....this seems like the good long term solution.
The rope will be doubled, so I get twice the strength, right?
But what about the knot to connect the two ends? ... the Zepplin Bend was mentioned (easy to untie after loading?)
What about the strength lost from the knot? The rope at the knot will be the weakest link right?

Thanks.
 
Knot/seam should be buried thru wraps from hit of impacts and loading.
>>So, any knot that holds should be okay, and easy to untie since not getting jammed with forces.
>>this would be true of knot 'seam' for holding hitch to tree/anchor and for making eyes as well, keep seams from primary loading zones.
>>work to not expose/risk seams to primary/full forces
So bury seam from forces, and focus on grooming parts taking hit
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Clock is WRONG, not just a little bit; REAL WRONG
"They should call it the Clockwork Orange Hitch.. it's criminal to use that thing." -JeffGu/TB
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Same principle elements, slightly stronger flavour/strength fave type setup amongst mountain/rescue:
image006.jpg

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In your pic and Clock: pulley pulls across rope column(s)
>>want teepee to pull out from trunk, the farther the better for sharper point showing straighter pulley pull down rope column/length properly.
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i threw math not to confuse but to show what is proper/why
>>then also how 'out of line' clock and your pic are with how those numbers work
AND they go across ALL examples, there is no escape, only blind bumping into if can't see...
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The wrap 2 pull 1 pic isn't that much different than yours or Clock
>>some turns and a protected seam from the direct hit
NOTE: biggest strength is at rope parts taking hit, flat to tree is wrong for this, real difference is the 'point' that serves out to pulley in wrap 2 pull 1
Big Difference is how most loaded , immediate loading of pulley pulls on the support legs directly to it
>>In Clock and your pic, this pull is PERPENDICULAR to the rope parts directly supporting against pulley
This leverages/wrenches against line strength
>>can you hold 20# inline at side or perpendicular straight out from chest longer????
>>which way is your own feels like architecture stronger?
>>if can get to where use such an imagery, and can look at rope and see that would be pull on arm, i say knowledge becomes more intuitive body sense; which also can give most immediate correct action in emergency...
Relax perpendicular pulls to birds beak / teepee point, that immediate pulls can go down more than across these strands/columns
>>would IMMEDIATELY make your pic and Clock better, then maintain buried seam away from hit/loadings
>>the flatter the teepee, the weaker the rope is, the Clock and your pic is FLAT >>can't get any worse ('cept maybe if pulling tight to flat beam rather than round spar) !!
>>longer and longer sharp point teepee is closer and closer to being a most proper eye
Flat vs. Eye are the 2 benchmark range extremes, that all the rest are between
>>Clock and your pic are at the wrong extreme end of that range pulling perpendicular across supports rather than INLINE
Strength being chased hear is 100% geometry, once have seam as weak link buffered from hits
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We say making doubled rope/eye gives about double strength in ruff math
>>but there are numbers out there that assume some loss and quote at at like 165%(KnudeKnoggin big advocate i believe, perhaps the SMARTEST rope/knot mind i've ever come across; that i have learned the most from) instead or 200% rope tensile
>>Much worse if rope is stiff and resists in any way eye bend
If making own eye sling for like Cow or Timber, would make long eye so only eye takes hit and the knot seam making eye is buried on tree so seam doesn't take primary hit. Personally i'd use Double Bowline w/Yosemite tie Off (affectionately known as DBY) on the long eye, making sure knot doesn't take hit, it is on the tree, maybe even rope strands crossing OVER eye too before seam/DBY receives hits.
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Extending that buffering loading to seam topic further AND ALSO add strength to Timber or Cow i prefer Round Turn around Standing Part/eye to pulley rather than simple Turn before commencing with rest of Cow or Timber.
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edit: in the word 'architecture' arch means not flat bridge etc. construction but rather they found arc to keystones to route force around flat construction(but still give flat service on top side to bridge etc.)
>> cosine of inline is 1, i read as 100% strength, less inline is lower cosine /less preserved strength percentage.
>>all the way down to flat is Zer0 cosine.
0-1 range multiplier of rated strength to find actual is all cosine is, from PURE INLINE(1) TO flat (0)
once again; Clock and your pic are on the low end of the preserved line tensile scale, hardly any cosine left.
This rope example is just a microcosm of the same rules of how ALL this works!
 
  • Thread Starter Thread Starter
  • #17
Thanks again for all the comments and ideas.... just went back and re-read (still need more time to study TreeSpyder's posts... but I did find the discussion from 2009 about the Clock Hitch).

Why not just tie a bowline in the end that you're clipping the carabiner to and cow hitch or timber hitch the tail?

So the bowline loop becomes the eye of the "sling" so to speak? ... i.e. home-made sling?


But with only a 1/2" 3-strand rope I figured the bowline would be a weak link.

How to get doubled 1/2" 3-strand rope strength? ... just double rope and do everything with the rope doubled?

Thanks any and all.
 
WOW
Man, i gotta tell ya......
You'd be surprised how many tree guys still can't tie a bowline.
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Certainly, certainly;
A simple wrap 3 pull 2 used in worst life rescue conditions, to bring rescuers and victims lives home safe
should give generous 2xTensile to your 3strand if has nice teepee/beak point
>>out of the 4 legs of line to pulley, no exposed 'seams'/knots or splices to primary loadings
>>at max spread of 60 degrees apart
>>should serve WAY OVER 2x rope strength to pulley support
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image006.jpg

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In the span between spread lines on front/pulley side of anchor support is best place for seams, as most buffered from loadings and visually inspectable.
The benchmark line tensile strength is outer limit, can't beat that, only add legs to it
4 exposed, pristine legs spread not too far apart is pretty strong.
Vulcan salute is 30 degrees spread check, take that as new meaning to "live long and prosper"; as a safety check to support angle spread at pulley!
>>forefinger and baby finger spread is 60 degree check
>>shaka thumb to baby finger hard spread is 120 spread, 60 deflection from PURE INLINE centerline
>>cosine is .5 which all else being optimal is 4 legs x .5 cosine = 2xTensile
>>if had 10ft 2x4 and leaned it against house at 60 degrees, would hit house at 5ft. up
>>10ft is potential x .5 = 5ft. at 60 degrees there is only 50% potential of line pull or board length(rise)
>>ALL THE SAME
sine of 60 would give percentage of distance from house of same 10ft potential length or potential of line tension
>>ALL THE SAME cosine is simply percentage of remaining original/potential column at given angle
>>whether measuring length or force, it is simply the same percentage of the potential/all lengths and forces are finite
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latest
 
YES,
very possible!

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Master Splicer Brion Toss Best 3 strand splice info/imagery:
People generally try to maintain the unraveled strands in round state as most pristine.
But rather should ribbon flat the 3 strands for greater surface area of friction as it weaves back thru Standing Part
>>this also disturbs the Standing Part least, that is what you are trying to leave pristine
The flat strands give greater frictions for security and disturb rope column least for most strength retention.
>>these words long ago for strongest 'knot'/permanent splice really helped me form my model imagery/re-confirm how completely the same principles remain consistent!.
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Favour healthy 'butane backsplice' on ends that stick out at splice finish; ball end impossible to pull back thru.
Still would favour long eye to leave splice as seam out of the hit.
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Favour Round Turn around Standing Part of any Timber, Cow or choke sling etc. (knots that bend own Standing Part as pull load leg to center as opposed to Clove or Round Turn based that feed most from side.)
 
Looks fine to me.
Just remember, though.
If you want to be a first class arborist, you need to find a way to add a skid steer to your pulling set up.
 
making it easy to set up and break down along with reliability is the goal.. if you have length of 1/2" line its pretty easy to double or triple wrap it around the tree... You don't need the nylon sling/connector, just go right through the pulley.... per spidy's diagram
 
  • Thread Starter Thread Starter
  • #24
Thanks again ALL for sharing your time, talent, knowledge, and experience with me.

All this info is helping me refine and understand things much more clearly.

Since I tend to gravitate toward the planning, organizing, thinking, theorizing about work more than the actual work itself --

I am therefore resolved not to post again until I have:

1. Carefully reviewed all comments in this thread and the "Clock Hitch" thread TreeSpyder (Kenny? ... may I call you Kenny?) mentioned -- especially TreeSpyder's posts -- just because they are harder for me to understand -- to digest as much as I can.
2. Rigged up a (even a mock) real life setup and post pictures for your (hopefully) consideration and comments/criticisms, etc.

Thanks again for this forum and for all your help.

Robert

P.S. Yes, Peter, thanks, I have been thinking about that that maybe I could try splicing a 3 strand rope. :)
 
Kenny's posts are usually very basic concepts but he has a terribly frustrating way of making them sound like Chinese trigonometry. He's done it for decades. I fully understand all the techniques he tries to describe but can't understand a word he posts.
 
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