Slings used for the crane- Fake plywood?

[TreeDr]

I would like to know what the personal preference is on crane slings. I've seen, and used, slings with steel eyes and slings with spliced eyes. I would also ask if anyone has used those 4x8x3/4 plastic sheets instead of plywood( with the diamond traction raisings) for any length of time. Do they really last and not break? Thanks Heckler

 

[Eric_E]

The sub I use for crane work uses 4 - 3/4" spliced eye slings. The same used to tie a block on. The 4 slings are attached to a lagre clevis through the eyes. The clevis is then attached to the hook. The slings can then be tied to a number of spots in the tree or on a stick. This keeps the load balanced.

[ December 10, 2001: Message edited by: Eric E ]

 

[Mark Chisholm]

I agree with Eric here. It is real important to balance the load. I think that, for the big stuff, I would either use dead eye slings (with an exotic core like spectra) or the endless loop type.

If you use the standard eye to eye nylon sling, there is only one layer of material in the eye. This usually means that the rating in choker mode is under 5,000 lbs. That is also with the 4" thick slings. However, with the endless loop nylon, a 2" thick sling has a choker rating of almost 10,000 lbs. The exotic core sling is about the same. The endless loop is much less exspensive though. They are around $40.00 for a 10' - 12' length. If you use big cranes- you need strong slings!

 

[TheTreeSpyder]

Wow, wee use only eye to eye cable chokers for crane work, they are always there with the crane.

If wee (the ants using the crane to move the matchstix), use a clevis, it is as a hitch for the choke on the tree (not on low diameter/ tightly curved pieces), not on the crane hook. i always tighten the clevis, then back it off about 1/8th turn to keep it from jamming tight. Eye see this as a lot easier.

Wee also schedule the angle of initial pull to lock closed the choke positively and at a high torqued position to tear off the hinge easily, that makes a big diffrence in the handling operation of these big pieces.

-KC

 

[BigJon]

I am guessing I have taken down more trees with cranes than most. In my experience I have used 1/2 new england with a bowline on bight on one end doubled up. I have used regular eye and eye webbing in combination with a clevis to make a choker.I have also used Tuflex slings. All seemed to work well and had there place. As for the black diamond mats to drive on I found they hold up well. I have dropped big wood out on them, bent them up and they always returned to there original shape. The most pleaseing is the way they smell. They smell like roor beer.

 

[Roger_Barnett]

I've very little experience craning shade trees. When I have, sling material seems adequate for smaller limb work.

When crane logging long evergreen sticks, the last few years the crane companies have alway had wire loop chokers, which we close with a shackle. They used to have the real heavy webbing, which we would undo from the ball, and install with no shackle required.

My log truck driver told me an incredible story. Some yahoo had somehow set a wire choker improperly around a small tree. The operator had not applied strong tension to set the bight. The cut was at the ground, the choker slipped off the end, the log fell and hit the crane cab, no one was injured. Phew!

Even more incredible was the crane operator's story. Another yahoo hotshot was ground cutting a large, long stick. Instead of making one cut straight through, he was fussing with some overlap mishmash. He kept telling the operator to take up tension. Anyhow, the 5/8 choker cable BROKE!!, leaving the tree teetering precariously between the house and the crane. Someone gingerly rode the ball up and quickly installed another choker and finished the cut. The crane operator was not without fault, I'd say, as he should have been watching his load scale.

I doubt if many of these "hotshots" are capable of determining the weight of a standing log very well. I'm pretty good, having a wood weight table , but a big stick did surprise me a bit recently. 23 inch top, 44 inch butt, 37 feet long, I thought 9000, it was 11200! No where near the crane limit at the extension, tho. Anyhow, two large firs, about 70-80 feet of wood each and a couple short hemlock logs, weighed 52000 lb.