Blocks & pulleys

[sohner]

Re: Blocks & pulleys

Because of the infinite range of adjustment whoopee slings are great for tree work.
On the relative strength scale they are, however, at the bottom.

As Don Blair states in his book "Arborist Equipment" ratings are an important factor in taking a systems approach to rigging. At all times, you must pay strict attention to Blair's Weak Link Law, which states: "The lowering line itself must be the weakest link in the rigging system."

 

[Mahk_Adams]

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I usually use a loopie and on occasion a tenex dead eye. I might try the round/ endless loop sling it would be quicker and easier to set up.

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Loopies and eye slings are adjustable so you can always create whatever length you want for the neck of the attachment knot. Round slings are not adjustable, so the neck typically goes from being too long, to just right, to just barely fitting.

 

[Mangoes]

To augment Mahk's post; too long will lower you rigging point, lengthen distance of fall and increase shock loads.

 

[Marc_H]

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To augment Mahk's post; too long will lower you rigging point, lengthen distance of fall and increase shock loads.

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Excellent point and the primary reason why I use the loopie, whoopie and fixed eye slings.

 

[sharkfin12us]

I had a rope snap that i was using for the port a wrap with 5/8's rope to tie port a wrap around the tree.I was blocking good size piece of oak.I used one inch rope and cmi yellow block i believe its rated at 20,000.When i made the cute the piece fell and snapped rope holding port a wrap.Port a wrap went from bottom of tree to the top near the block and luckily piece i was blocking down did not go far.Now i use a stronger rope to tie to port a wrap.When i am blocking big wood i use the heavy duty aluminum block with one inch rope works havent had a problem since.I want to buy 3/4 inch woppi sling one of these days.I have whoppi sling but its good for 3 to 4 foot trees.I want to get the bigger one.Just wanted to share that experience.

 

[Blinky]

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Another option is to attach the block to the tree using a fixed eyed sling. This method allows for more flexibility when working on a straight stem. The prefered hitch for attachment is the cow hitch. Easy to tie and untie for moving down the stem.

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That's how I do it. I like the CMI one ton stainless for most work. Big tops though... the big CMI.

 

[Norm_Hall]

[ QUOTE ]
I had a rope snap that i was using for the port a wrap with 5/8's rope to tie port a wrap around the tree.I was blocking good size piece of oak.I used one inch rope and cmi yellow block i believe its rated at 20,000.When i made the cute the piece fell and snapped rope holding port a wrap.Port a wrap went from bottom of tree to the top near the block and luckily piece i was blocking down did not go far.Now i use a stronger rope to tie to port a wrap.When i am blocking big wood i use the heavy duty aluminum block with one inch rope works havent had a problem since.I want to buy 3/4 inch woppi sling one of these days.I have whoppi sling but its good for 3 to 4 foot trees.I want to get the bigger one.Just wanted to share that experience.

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What was the rope snap attached to, the Porty? If that's the case, during drop hitch situations, the drop length increases which would increase the force. Girth hitch the fixed eye of the whoopie to the porty.
I have a suggestion; invest in a spliced eye sling instead. In my opinion, you can't snug up a whoopie like you can an eye sling

 

[TheTreeSpyder]

Too snug/ too flat a teepee can raise force in the choke though..

 

[fhfr436]

[ QUOTE ]
[ QUOTE ]
I had a rope snap that i was using for the port a wrap with 5/8's rope to tie port a wrap around the tree.

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What was the rope snap attached to, the Porty?

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Initially, I misread the original as you apparently did. I thought he was referring to a 'rope snap' (piece of hardware), but he's actually saying that his rope snapped - the one that he used to secure the porty.