Opps with a crane....

[Matt Follett]

Okay Dan... you got me thinking here.. how about something similar to a spider sling... the main "choker would be tied off at the bottom... lets say 1" heavy braid... then a second attachment point set up.... like say a prussick loop on this long sling... hook the prussick to a heavy loop runner... that way you could adjust the distance between the points quickly... and if the top attachment point failed... both would still be connected... my earlier thoughts of two attachments was good.. but tough to rig to get a balanced load... may still have uses though....

 

[bottlefed89]

Interesting thread, I haven't done too much crane work, I'm still trying to learn proper rigging for a crane. What other mistakes have some of you made that the rest of us should be aware of??
greg

 

[John Paul Sanborn]

I agree with the assesments here

1. the attatchement limb was too small for the load
2. The union of said limb looks included
3. multiple attatchment points should have been used

Choked loopes so you can adjust the sling length for better balance of the load.

Any type of balancer sling would have worked, I've seen some multi legged ones made by splicing nuts, then you use big eye slings attatched with a 'Klem' hitch to adjust ballance

 

[Gord]

best choice would have been to use two chokers. just take multiple wraps with the longer leg to equal the lengths...simple and safe.

 

[Jumper]

Was the title Ops or Oops??? Murphy strikes again, glad the damage was minimal.....

 

[murphy4trees]

anti-included

MM's point about a wide angle and thus no included bark is well taken and in fact in my thiunking is the reason for the failure...
The sharp bed in the wood below the choker created what is in effect a giant lever being pulled on by all that weight below.... That to me is the main lesson here...

Learn to choke at pont in line with the weight... Also like treeco's suggestions... It's nice to have so many years of experience at work in situations like this.... maybe a thread like this can even save a life down the road..

 

[John Paul Sanborn]

I was looking at the way the limb seperated and it looks liek there may have been a seam there. I've seen a lot of red oak with wider angles hat have imperfect unions.

So I guess we argree on improper attatchment...

 

[murphy4trees]

JPS wrote "So I guess we argree on improper attatchment..."

Yes, and no.... yes there was probably a weak attachment.... and no that alone did not cause the failure..... the angle of the limb was the primary cause, compounded by the weak union... And that weak union is not included bark, as MM rightly pointed out...

keeping the choke point in line with the weight will probably allow safe choking at a smaller diameter part of the limb than anyone here would "feel" comfortable with.... might be fun to try it in non critical situations.....

 

[Mahk]

...keeping the choke point in line with the weight will probably allow safe choking at a smaller diameter part of the limb than anyone here would "feel" comfortable with.... might be fun to try it in non critical situations.....

Try breaking a toothpick by pulling it lengthwise...

Mahk

 

[Matt Follett]

Hey guys... I think we're headed down the right chain of events... the funny thing about it was... while in the tree, that looked like the point "most in line", that's why I chose it... from the picture, it sure doesn't look that way at all eh! with regards to the bend.. maybe I saw it, maybe I didn't... I do remember looking at the union itself... thinking "well with the straight line pull, hanging vertical it will be alright"....

My lesson learned... spend more time contemplating.. and use two chokers, particularily on funny brush tops!