Knotless Rigging Question

[TC262]

When rigging small and medium sized branches I use loop runners and connect them into a steel carabiner. When I get into lowering the trunk wood is it acceptable to half hitch then girth hitch my rigging line using my biner or should I remove the biner and tie in a running bowline like I have been doing?

 

[imagineero]

That's too general of a question to answer. Would you like to provide some more details as to the rigging scenario; trunk size, negative rigging or rigging from a high point, size of pieces, size of rope, and lowering device? There are no absolutes, it's horses for courses and you'll get better advice if you give more details.

Shaun

 

[sgreanbeans]

U can leave the biner, just make sure that it is not loaded against the gate and you have a big KN rating. For rigging anything of real weight, I use +50kn steel. Small stuff 24kn.

 

[TC262]

That's too general of a question to answer. Would you like to provide some more details as to the rigging scenario; trunk size, negative rigging or rigging from a high point, size of pieces, size of rope, and lowering device? There are no absolutes, it's horses for courses and you'll get better advice if you give more details.

Shaun

I was mainly referring to negative blocking scenarios. For an example let's say a 4 ft long 24" oak log. I'd be using my 3/4" cmi arborist block, 5/8 stable braid, a large stainless porty, and a 50kn biner. Now where I'd normally tie a half hitch and a running bowline to the piece to be lowered would it be an acceptable practice to replace the running bowline with a biner girth hitched to the log (I'd still be keeping the half hitch)? I don't really see a problem with it but thought I'd ask a few pros before I have to find out the hard way.

 

[TC262]

I always use rope only when rigging down a trunk. No hardware, anywhere.

This is what I have been doing but was looking into alternatives for simplicity.

 

[beastmaster]

I normally use knots on bigger stuff, but just last week i used some 6ft 2in straps on a big horizontal leader. I had to take short fat pieces and dead catch them and worried a rope might slip off them. I girth hitched the strap on, hooked it up to a steel biner had two blocks one up high, and one on the leader and cut and caught each piece over a roof. Worked like a charm. Some of them were maybe 300 pounds. One potential problem using a strap or sling on negative rigging is you'd need a lot of different sizes so as not have to much slack in your rope between the piece and block.
I tried using my big steel caribiner before to clip the rope on a piece before but the weight of biner would pull the rope down and I couldn't get it tight.

 

[treebilly]

I'm not a big fan of using caribiners to choke something off. It puts force on it in a way that is not intended. If you notice there are no stamps for the bending Kn on them

 

[Pelorus]

Steel biners work fine. Use them all the time negative blocking stuff weighing in excess of 500 lb.
This is something I have been doing for in excess of 15 years without mayhem ensuing, and almost all my treework involves removals.
The marl preceding the attached biner is going to absorb much or most of those kN's. I don't bother with loop runners or straps, but rig the lowering line directly to the piece being lowered (talking about negative blocking not speed lining).
The groundies or absolute strangers I work with are about as incapable of untying knots as tying them, so using a biner speeds things up. Another benefit to using a biner is when a groundie decides to be helpful and pull your lowering line back up to you....the biner stops at the block. An unknotted rope doesn't.