I used to know of a knot that involved using three loops in the line to make an easy to untie come along but I can't remember how to tie it. Set up is I've got a running bolin attached to the tree and now I'm taking a 1/2 wrap around a nearby tree and trying to make a loop in the line in front of the 1/2 wrap so I can feed the end of the line through the loop to wrench the tree I'm cutting over. Man I just can't remember that knot!
knot used to make a come along?
- Thread starter woodville
- Start date
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You mean a trucker's hitch? 3:1 advantage?
http://www.animatedknots.com/trucke...ge=LogoGrog.jpg&Website=www.animatedknots.com
http://www.animatedknots.com/trucke...ge=LogoGrog.jpg&Website=www.animatedknots.com
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ddhlakebound
Addicted to ArboristSite
I use a butterfly for midline attachments. Its probably easier to run a search here to see how to tie it, describing knot tying isn't my strength.
When I do this, I attach a biner and micro pulley to my midline knot, and a block at my anchor point, so you are not fighting friction as you are trying to pull. It's also handy to attach a prussic loop at your anchor, to hold your tension, so once you pull it to where you want it, slide the prussic up, and it holds itself.
When I do this, I attach a biner and micro pulley to my midline knot, and a block at my anchor point, so you are not fighting friction as you are trying to pull. It's also handy to attach a prussic loop at your anchor, to hold your tension, so once you pull it to where you want it, slide the prussic up, and it holds itself.
ddhlakebound,
Yours is the better way and is easier on the rope as well.
Yours is the better way and is easier on the rope as well.
Mike Barcaskey
ArboristSite Operative
quick and easy, put a bowline in the line, carabiner in the loop to run the end through. bowline unties easy.
though I much prefer to use a couple of pulleys
though I much prefer to use a couple of pulleys
begleytree
H. sapiens moderatus
Climbah in Mass
ArboristSite Lurker
Sounds like the butterfly to me
Great Midline hitch when come along to pull over trees.
Great Midline hitch when come along to pull over trees.
beowulf343
Addicted to ArboristSite
Bowline on a bight.
BostonBull
Addicted to ArboristSite
Bowline on a Bight or a Butterfly.
begleytree
H. sapiens moderatus
the butterfly is not the same knot as the 3 ring circus, close though. neither is the rope saddle/ bowline on a bight.
-Ralph
-Ralph
Tree Machine
Addicted to ArboristSite
It's honestly easier to slap an ascender on, midline, and clip a biner and a pulley to the bottom of the ascender. It's immediately adjustable and removable.
I prefer a petzl protraxion as the midline pulley as it is a pulley / internal cam, all-in-one, that when you tension the rope, it grabs the rope, preventing it from going backwards. This is real important in pulling over trees with a mild back lean. It's quicker in setting up and disassembling than a series of knots, and it's the right piece for the place your talking about. However, it's not at all what you're talking about.
As far as a knot, for ease and quickness of setup, and bombproof security and ease of disassembling, a classic truckers hitch as described in WRW's link above, but create your midline fig 8 with sticks. Create a big bight in the rope, do a simple overhand knot, keep it real loose. Find two dead sticks, pinkie diameter, each more or less the length of your hand. Insert the two sticks through the body of the knot, then tighten it down. When using 2:1 or 3:1 systems, you can apply a lot of force to an inline knot, making it really difficult to untie. By simply snapping the sticks in two you release the knot and can move on to better things. On a tree job site, there are always going to be dead sticks at hand, so this is a nice one to add to your bag of tricks.
I prefer a petzl protraxion as the midline pulley as it is a pulley / internal cam, all-in-one, that when you tension the rope, it grabs the rope, preventing it from going backwards. This is real important in pulling over trees with a mild back lean. It's quicker in setting up and disassembling than a series of knots, and it's the right piece for the place your talking about. However, it's not at all what you're talking about.
As far as a knot, for ease and quickness of setup, and bombproof security and ease of disassembling, a classic truckers hitch as described in WRW's link above, but create your midline fig 8 with sticks. Create a big bight in the rope, do a simple overhand knot, keep it real loose. Find two dead sticks, pinkie diameter, each more or less the length of your hand. Insert the two sticks through the body of the knot, then tighten it down. When using 2:1 or 3:1 systems, you can apply a lot of force to an inline knot, making it really difficult to untie. By simply snapping the sticks in two you release the knot and can move on to better things. On a tree job site, there are always going to be dead sticks at hand, so this is a nice one to add to your bag of tricks.
This is of curse 3x Input - Friction. So, a krab rather than rope in redirect positions would give 20% less friction; but still be ~30% at 1st redirect? The accumulated friction effects from multiple redirect points in system would be a more geometric/multiplying than additive accumulation. If given choice i think redirect closest to input (dynamic redirect) should be most efficient position/pulley etc.
Pulleys have different efficiencies. The slip of bushing around axle not quite as efficient as bearings; but bearings more impact sensitive. Then the sheave to axle diameter ratio; gives leverage over the bushing or bearing frictions. In larger sheaves, the efficiency between bushing and bearings is expen$ive; as for just a few more percentage points of efficiency, the bearing pulley can be ~2+ times the cost of the less delicate bushing. But, in especially multi pulley systems with the accumulated multiplying frictions; people pay well for the bearings for lifting/pulling. If using Z-Rig for lowering/ extending jig to control load and not lifting/compressing jig; we want the frictions; as helping us (until they are hard on rope.
Tight bights of redirects of rope reeved thru self or krab; weaken rope by taking the inner part of the redirect bight out of pulling service. Cam grabs can damage ropes and are usually made more for bodyweight than load weights. Can also have a one way grab with a prussik on output end of a redirect point. Then can relax between pulls, and/or impact into them. But, if prussik (or checking cam) is placed at the dynamic redirect (not on anchor), the pull is 3x, but the hold of prussik is only 2x. Likewise prussik on static redirect of anchor in Zrig would only hold 1x. Especially if using cams for the hold; these points not bearing more than the 1/3rd of load that your hand pull takes, can be easily overlooked, and damaging. Also, the rig will stretch out more at the hold point; for each leg of line now bears more load; especially noticeable at full extension/ more line area to stretch more.
If we Zrig; with tail of load line as shown; the line 'below' dynamic/moving redirect that goes to static redirect on anchor; gets skinny from stretch from stretch of 1x effort, and more chance of slippage. A Butterfly etc. instead does not 'worry' about this point. But, then no adjust-ability; only 1 pull length. Better is to piggy back a Butterfly bearing system onto a prussik etc. on load line; then the part of load line 'below' the prussik is relaxed and 'fat' so less chance of slippage.
The Z-rig gives 3x-Friction; with 2x pull on anchor(open 'circuit' gives different pulls on load, and anchor pivot). But can be 2Handed for 4x pull of 1 hand; but then 4x on anchor also (2Handing closes the 'circuit' of force flow and thereby makes the load and anchor pulls equivalent/ no opening in circuit to change loading between these 2 points in the closed circuit). But, the Frictions reductions to force potentials will be less with 2Handing than same force or force multiplier with non-2Handing methods; for less loss.
At finish of tightening Z; can anchor input away from dynamic redirect and sweat more purchase from it usually; to then be tripled by the system. If using as a tie down for transport, now all lines in Zrig are tight/ will resist bending; so can bend whole jig with perpendicular force; for really, really leveraged tightening.
i tell ya; i'm knot crazy!
Pulleys have different efficiencies. The slip of bushing around axle not quite as efficient as bearings; but bearings more impact sensitive. Then the sheave to axle diameter ratio; gives leverage over the bushing or bearing frictions. In larger sheaves, the efficiency between bushing and bearings is expen$ive; as for just a few more percentage points of efficiency, the bearing pulley can be ~2+ times the cost of the less delicate bushing. But, in especially multi pulley systems with the accumulated multiplying frictions; people pay well for the bearings for lifting/pulling. If using Z-Rig for lowering/ extending jig to control load and not lifting/compressing jig; we want the frictions; as helping us (until they are hard on rope.
Tight bights of redirects of rope reeved thru self or krab; weaken rope by taking the inner part of the redirect bight out of pulling service. Cam grabs can damage ropes and are usually made more for bodyweight than load weights. Can also have a one way grab with a prussik on output end of a redirect point. Then can relax between pulls, and/or impact into them. But, if prussik (or checking cam) is placed at the dynamic redirect (not on anchor), the pull is 3x, but the hold of prussik is only 2x. Likewise prussik on static redirect of anchor in Zrig would only hold 1x. Especially if using cams for the hold; these points not bearing more than the 1/3rd of load that your hand pull takes, can be easily overlooked, and damaging. Also, the rig will stretch out more at the hold point; for each leg of line now bears more load; especially noticeable at full extension/ more line area to stretch more.
If we Zrig; with tail of load line as shown; the line 'below' dynamic/moving redirect that goes to static redirect on anchor; gets skinny from stretch from stretch of 1x effort, and more chance of slippage. A Butterfly etc. instead does not 'worry' about this point. But, then no adjust-ability; only 1 pull length. Better is to piggy back a Butterfly bearing system onto a prussik etc. on load line; then the part of load line 'below' the prussik is relaxed and 'fat' so less chance of slippage.
The Z-rig gives 3x-Friction; with 2x pull on anchor(open 'circuit' gives different pulls on load, and anchor pivot). But can be 2Handed for 4x pull of 1 hand; but then 4x on anchor also (2Handing closes the 'circuit' of force flow and thereby makes the load and anchor pulls equivalent/ no opening in circuit to change loading between these 2 points in the closed circuit). But, the Frictions reductions to force potentials will be less with 2Handing than same force or force multiplier with non-2Handing methods; for less loss.
At finish of tightening Z; can anchor input away from dynamic redirect and sweat more purchase from it usually; to then be tripled by the system. If using as a tie down for transport, now all lines in Zrig are tight/ will resist bending; so can bend whole jig with perpendicular force; for really, really leveraged tightening.
i tell ya; i'm knot crazy!
Thanks for the help it appears to be a butterfly just the way I learned or forgot how to tye it is diffrent.http://www.animatedknots.com/alpinebutterfly/
yeah i saw an old timer make it, it was rope on rope though, the loops took the stress and made the knot easier and possible to untie
NickfromWI
Addicted to ArboristSite
The knot you're thinking of, with 3 loops and easily removable:
Slip Knot on a Bight...then run the running end through all three loops of the slip knot.
love
nick
Slip Knot on a Bight...then run the running end through all three loops of the slip knot.
love
nick
digga
ArboristSite Lurker
hi very interesting topic as I use the truckers hitch sometimes when cutting alone to pull over the tree I'm cutting am interested in what’s been said about using a petzl protraxion to keep the tension on the rope as i normally just end up tying off with a knot which is a pain if you want to take up some more slack in the rope. Could someone please explain how you set the petzl protraxion( or similar device ) up and where you put it to keep the tension on the rope and allow you to pull more slack up?
A prussik lock/safety is similar. Only spreads grab along more line, and on outside, sets by pulling away from redirect point. Cams concentrate grab in one area, and pinch thru rope; better when the core is the force carrier as opposed to the sheath. Toothed cams can be fairly aggressive to rope.
Where the prussik sets by pulling away from redirect point, the cam sets by pulling into the redirect, so is set on the opposite side of it's pulley than you'd set a prussik. In the Zrig/ Truckers; you can set Traxion on krab by its becket at butterfly position, with red cam button on the hand pull side. Reeve rope thru Traxion pulley. Close cam on rope.
Now should give a 1 way, 3:1 pull. Notice, your hand pull is 1/3rd the load pull; but when the cam holds it has 1 leg less of pull on load than hand pull has; so cam is holding 1/2 the load pull; not 1/3rd, so watch safety ratings; just the same as prussik in same position; but on opposite side of sheave (so cam sets pulling into its pulley, prussik sets pulling out of it's pulley/ tended by the pulley.
Where the prussik sets by pulling away from redirect point, the cam sets by pulling into the redirect, so is set on the opposite side of it's pulley than you'd set a prussik. In the Zrig/ Truckers; you can set Traxion on krab by its becket at butterfly position, with red cam button on the hand pull side. Reeve rope thru Traxion pulley. Close cam on rope.
Now should give a 1 way, 3:1 pull. Notice, your hand pull is 1/3rd the load pull; but when the cam holds it has 1 leg less of pull on load than hand pull has; so cam is holding 1/2 the load pull; not 1/3rd, so watch safety ratings; just the same as prussik in same position; but on opposite side of sheave (so cam sets pulling into its pulley, prussik sets pulling out of it's pulley/ tended by the pulley.
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Tree Machine
Addicted to ArboristSite
I tend to use the ProTraxion to pull over small trees. Generally I go 1:1, upper tree, out to the anchor, through the ProTraxion and back to the base of the tree being cut. The advantage here is you can pre-tension, make your cuts, set the saw aside and your pull rope is right there. Place your boot against the backside of the trunk, push with your foot, pull with your rope. But that's because I generally work alone. If I have help, I'll set the rig as drawn on page 1, a 2:1 Z.
May I repeat that I do this on small fells where I can't trust it to be a simple fell over or a push-fell. The proTraxion is a rated device, but as Spidey point out, too much force can have a damaging effect on ropes.
On larger trees where there is actually room to fell it (rare where I work)I've come to set two ropes, one on the ProTraxion system, the other to a come-along. If there's chance of damaging ANYTHING, you should not trust the pullover to a single rope. Felling a tree is generally considered faster than chunking it down...... unless an accident happens. Two ropes is good practice and the extra time, if it prevents even a minor occurance, is worth the time spent. An accident can make a professional look like a fool in a hurry.
May I repeat that I do this on small fells where I can't trust it to be a simple fell over or a push-fell. The proTraxion is a rated device, but as Spidey point out, too much force can have a damaging effect on ropes.
On larger trees where there is actually room to fell it (rare where I work)I've come to set two ropes, one on the ProTraxion system, the other to a come-along. If there's chance of damaging ANYTHING, you should not trust the pullover to a single rope. Felling a tree is generally considered faster than chunking it down...... unless an accident happens. Two ropes is good practice and the extra time, if it prevents even a minor occurance, is worth the time spent. An accident can make a professional look like a fool in a hurry.
Also with a tension hold; a flexible line becomes stiff. The stiffness gives resistance to bending. This makes the rope now leverageable not just by redundant inline pulls; but now leverage able by perpendicular pull or push (when usually rope only gives inline force usage and outputs, but also rope usually only takees pull and not push as an input). But only for a short distance; but of very high leverage. Another plus of a hold is our ability to impact the system. Without a rope hold, we must hold rope and then pull, can't use impact force as an input as well.
So if tree etc. as load will not move and cannot place any more inline force into 1:1 or 3:1 etc.; might not have to cut more. If it is close enough to bending hinge; you can pull across tightend line for a very high leverage return (but of a short distance\ arc of bend. The sudden change in force also has impact force; applying it even more quickly\sharply creates even more of a sudden impact of change. All in all if this works, less cutting, less work and stronger hinge. Just by applying lesser known perpendicular force to line.
We only think of inline force and pull for rope; cuz mostly that is what works; and we envision rope as its more familiar non-tensioned\relaxed form. Where only inline pull works. But once tensioned the rope has charachteristics of both a flexable and non-flexable\levergeable device; only inline forces can be used on the former; both on latter; but inline force on non-flexable gives no advantage(cannot go around pulley etc.).
So if tree etc. as load will not move and cannot place any more inline force into 1:1 or 3:1 etc.; might not have to cut more. If it is close enough to bending hinge; you can pull across tightend line for a very high leverage return (but of a short distance\ arc of bend. The sudden change in force also has impact force; applying it even more quickly\sharply creates even more of a sudden impact of change. All in all if this works, less cutting, less work and stronger hinge. Just by applying lesser known perpendicular force to line.
We only think of inline force and pull for rope; cuz mostly that is what works; and we envision rope as its more familiar non-tensioned\relaxed form. Where only inline pull works. But once tensioned the rope has charachteristics of both a flexable and non-flexable\levergeable device; only inline forces can be used on the former; both on latter; but inline force on non-flexable gives no advantage(cannot go around pulley etc.).
clearance
Addicted to ArboristSite
Yup, simple, works good.
