What knot to use for this situation...

Arborist Forum

Help Support Arborist Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

Plasmech

Addicted to ArboristSite
Joined
Dec 13, 2008
Messages
1,164
Reaction score
82
Location
Aston, PA (19014)
This is just a hypothetical situation, would probably never do this exactly, but...

Say I have two trees. I tie a running bowline on one, close to the ground, say 6 feet up, and then I want to tie in to the other tree, so I'll have like a clothe-sline. Is there a knot I can put on the second tree that will allow be to pull on it (or its tail) as hard as possible and have the slack come out, permanantly, of the "clothesline"? Sort of like a big wire-tie, or a "ratcheting knot", you get the idea. I guess a Blakes would work but doesn't seem permament, like it could easily work its way lose.

Or say I'm up in a tree and want to drop a chunk. I tie a bowline to the top of my chunk and my ground helper pulls it toward the face, except as backup, I want the rop tied to a tree base so if he slips, the chunk can't come back the other way. If he ties in to a tree base and takes all the slack out, he can just sort of push down / sit on the rope to apply tension...

I could think of many uses for this knot, one simple one is tying between tie-downs in my truck. An ideas? Thanks.
 
Thetreespyder calls it Z rig. http://www.mytreelessons.com/Z-Rig - Pattern of Pull.jpg It comes up in very small print, but scroll over it and click on it and it becomes legible.

Slippery bowline on one tree, butterfly or bowline in a bite between the trees, go around second tree, go through loop in butterfly or bowline in a bite, pull like hell ("Sweat it In"). Lock it down with half hitches either around the tree, back through the butterfly, or to a third tree or post. Spydie gives a very good explaination of the mechanical advantage. You can add mechanical advantage by reducing friction if you put a pulley in the butterfly or bowline in a bite and use it rather than the rope on rope interface described in my first sentence of this paragraph.
 
Last edited:
Bowline on a bight? Truckers hitch/rope come-along, and lock it off with a few half hitches? Gives you some mechanical advantage too.
i second the truckers hitch. you can also pull tight take a wrap then go over the working line, pull tight and wrap again. you can repeat this process until your out of tail.
 
Yea the Trucker's hitch seems like the way to go. The Z rig is interesting also.

I guess I could cheat and use puleys, biners, and a rope grab too.
 
Yea the Trucker's hitch seems like the way to go. The Z rig is interesting also.

I guess I could cheat and use puleys, biners, and a rope grab too.
using a mechanical advantage for maximum effect is not cheating!
 
The truckers hitch is much harder to untie. The alpine butterfly has the highest rating for this application (mid-line attachment), but it too is hard to untie once set.

Fastest and easiest to tie, MUCH easier to untie: the man-harness knot. It almost can't be made to bind up.

This mid-line attachment knot problem was well discussed in another thread: http://www.arboristsite.com/showthread.php?t=77820&highlight=pioneer+knot

the manharness knot starts here: http://www.arboristsite.com/showpost.php?p=1187344&postcount=37

Read the whole thread for lots of good commentary.
 
Last edited:
prussics slip under a big load and will burn your rope pretty good,
again the truckers is good but not if heavily loaded,
the butterfly is good and not to hard to untie but is easy to tie wrong
so unless you are using it regular ,, its best left alone
the simpleist would be the bowline on a bite , easy to tie ,, used regular so groundies etc will remember it , takes a big load, is easy to untie,
you really should be using a portawrap for lowering anything substansial
and if there is a chance your groundie could slip or fall over and it could all go
t*ts up then stop and think about it coz you are doing something wrong
 
Prussics slip under a big load? I've used a GRCS to tighten a zip line with a 5to1 pulley system using a prussic and it didn't slip. Tie a swabisch with 5 wraps, you should be fine.
 
I use the 3:1 (Z-rig) almost exclusively for what you're talking about, backed up with 2 half hitches. The only problem is that when you tension it, the bight around the trunk tends to creep up. Sometimes if this is a problem I'll wrap a strap around the tree and run the bight through a biner.
 
Last edited:
yep but i do mean a big load, if plas is looking to use it as a backup on a rigging line it will need to take a fair weight as a fail safe. as you probably know a 300 lb piece will weigh in as much as 1500lb if droped more then a meter etc etc, and when it slips it burns very hot,
 
Prussics slip under a big load? I've used a GRCS to tighten a zip line with a 5to1 pulley system using a prussic and it didn't slip. Tie a swabisch with 5 wraps, you should be fine.

With all due respect to all, I think that if Prusiks didn't work, most of us here including me would be kinda...dead...
 
With all due respect to all, I think that if Prusiks didn't work, most of us here including me would be kinda...dead...

Yes, they do work for body weight. In rescue, we use them for loads up to 600 lbs. (tandem triple wrap). They are designed to slip under heavy loads, though, so for big wood, I wouldn't use them. A prusik would be useful as a progress capturing device to take up your slack in this situation, but I would lock off the rope some other way (a tensionless hitch, perhaps?)
 
This is so simple guys! If you want a mid-line knot that won't slip, tie one! Several good options already discussed.

If you want a "movable" knot that won't hold as much weight, use a prussic or it's equivalent.

What? Can't you learn more than one or two knots? Use the right knot for the right place.
(and yes, my groundmen have trouble with knots, too. Teach 'em!)
 
Yes, they do work for body weight. In rescue, we use them for loads up to 600 lbs. (tandem triple wrap). They are designed to slip under heavy loads, though, so for big wood, I wouldn't use them. A prusik would be useful as a progress capturing device to take up your slack in this situation, but I would lock off the rope some other way (a tensionless hitch, perhaps?)

I will say that when using a Prusik to rappel down, sometimes when you let go of it to stop, that 1 second delay before you fully stop seems like an hour...
 
The truckers hitch is much harder to untie. The alpine butterfly has the highest rating for this application (mid-line attachment), but it too is hard to untie once set.

I'd just use a slip knot as the eye of the trucker's hitch.
 
I use a directional 8 for my midline knot. It seems like a slipknot would lock down on your rope, making it hard to pull.
 
Back
Top