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mechanical advantage

smith ferguson

smith ferguson

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I need to get a 3 to 1 advantage on my rigging line to reduce limb drop post cut. I have a 3/4 inch rigging line. The only hardware I have that fits a 3/4 inch rope is my pulley block that will be in use. Is there another piece of hardware I can use with a portawrap to achieve the 3 to 1 advantage or should I purchase another pulley. If so, which one do you recommend?

Here is
skip to minute 3:29
 
BC WetCoast

BC WetCoast

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You can use steel biners, but it's a pretty tight bend radius. What size branches are you cutting that you need 3/4" rigging line? Can you get by with 1/2" and get some 2" pulleys?
 
CT arborist

CT arborist

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When there are options: place a block at the crutch and cut smaller pieces to be lifted by the groundman at the portowrap. Bigger limbs you can start practicing trying them at a point where the limb would hung almost horizontally. It's hard to get it right almost everytime. Or maybe use two rigging points?
 
Groundman One

Groundman One

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I need to get a 3 to 1 advantage on my rigging line to reduce limb drop post cut. I have a 3/4 inch rigging line. The only hardware I have that fits a 3/4 inch rope is my pulley block that will be in use. Is there another piece of hardware I can use with a portawrap to achieve the 3 to 1 advantage or should I purchase another pulley. If so, which one do you recommend?

Here is
skip to minute 3:29
Oh my... :eek:

I'm not crazy about how he grabs the rope with his hands to keep the tension to reposition. That's bad in so many ways.

We use a separate line on a separate attachment point to pull the rigging line that feeds into the porta-wrap. When you have the pull done, you lock off the rigging line on the porta-wrap and then release the tension on the separate pulling line. You are always secure that way.

Doing it by hand like that with one line gets your fingers in a tensioned rope and you risk injury and losing control of the load. Maybe both at the same time. Not to mention what the consequences might be for the climber.
 
smith ferguson

smith ferguson

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When there are options: place a block at the crutch and cut smaller pieces to be lifted by the groundman at the portowrap. Bigger limbs you can start practicing trying them at a point where the limb would hung almost horizontally. It's hard to get it right almost everytime. Or maybe use two rigging points?
Thanks.
 
smith ferguson

smith ferguson

ArboristSite Lurker
Joined
Apr 9, 2019
Messages
19
Age
35
Location
Memphis
Oh my... :eek:

I'm not crazy about how he grabs the rope with his hands to keep the tension to reposition. That's bad in so many ways.

We use a separate line on a separate attachment point to pull the rigging line that feeds into the porta-wrap. When you have the pull done, you lock off the rigging line on the porta-wrap and then release the tension on the separate pulling line. You are always secure that way.

Doing it by hand like that with one line gets your fingers in a tensioned rope and you risk injury and losing control of the load. Maybe both at the same time. Not to mention what the consequences might be for the climber.
Thanks
 
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