Ax-man
Addicted to ArboristSite
I think it was Mike Maas put this up, awhile back, I printed it and saved it. I have no idea how this might look on other computers, I used the same pixel size I use for the pictures.
Friction saver use for rigging?
- Thread starter Dadatwins
- Start date
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NickfromWI
Addicted to ArboristSite
I'm sure ax-man obtained written permission before putting that up here. Either way, he put it up, so now it's property of Arboristsite, not whoever originally published it.
That is a clever way of rigging a block up in to a tree, but I don't like how it pulls sideways on the splice. I guess if you tie a knot there, some knots are designed to take a pull from that angle.
love
nick
That is a clever way of rigging a block up in to a tree, but I don't like how it pulls sideways on the splice. I guess if you tie a knot there, some knots are designed to take a pull from that angle.
love
nick
John Paul Sanborn
Above average climber
NickfromWI said:
Nick, I don't think I ever told you to shut up before...but this is getting old.
NickfromWI
Addicted to ArboristSite
I am just being ridiculous...
...like the guidelines.
...like the guidelines.
vinnie
New Member
why dont u just run a block from the tree . u can set it upfrom the ground
John Paul Sanborn
Above average climber
Welcome to ArboristSite Vin!
Runing a fishpole retrievable (anchored ar the base of the tree) is often a good way to go, but has the disadvantage of putting near twice the force of the load on the rigging point then if you anchored the block at the rigging point.
This happens because you are using a static pulley in your rigging point. The MA of the pulley doubles the force of the rigged load on the pully, so this quadruples the force appled to the rigging point (crotch) our retrievable block runs through. (minus any angle of deviation, friction and rope streach for you sticklers out there).
There are other ways to reduce this, such as running it through 2 crotches, thus reducing the angle of deviation ("On Rope" figure 4-49, pg 84) 10 around 140% vs 200%.
In other words, we with a fixed retrievable we can work heavire on a higher rigging point.
Runing a fishpole retrievable (anchored ar the base of the tree) is often a good way to go, but has the disadvantage of putting near twice the force of the load on the rigging point then if you anchored the block at the rigging point.
This happens because you are using a static pulley in your rigging point. The MA of the pulley doubles the force of the rigged load on the pully, so this quadruples the force appled to the rigging point (crotch) our retrievable block runs through. (minus any angle of deviation, friction and rope streach for you sticklers out there).
There are other ways to reduce this, such as running it through 2 crotches, thus reducing the angle of deviation ("On Rope" figure 4-49, pg 84) 10 around 140% vs 200%.
In other words, we with a fixed retrievable we can work heavire on a higher rigging point.
Dadatwins
Addicted to ArboristSite
Did the job today, with a block set from the ground tied off at the base. Thanks for the ideas and suggestions, don't know why I did not think of hanging a block in the tree from the ground. I guess the easiest solution is usually not the most obvious.
Samthehorse
ArboristSite Lurker
Shock loads may be present!
There will be moments as you complete each cut that the rope/friction-saver will take the majority of the weight, and therefore, I think you would be wise to plan on a rigging system that can bear the full weight, without danger to yourself. Is there a possibility that the oak will jam in the pine as it is lowered? Re: the stamped swl on the device, it would be worth attempting to find out what it's expected breaking strain is. They obviously do allow a fair margin, not so much for our safety, but to avoid their own liability issues.
Good luck!
There will be moments as you complete each cut that the rope/friction-saver will take the majority of the weight, and therefore, I think you would be wise to plan on a rigging system that can bear the full weight, without danger to yourself. Is there a possibility that the oak will jam in the pine as it is lowered? Re: the stamped swl on the device, it would be worth attempting to find out what it's expected breaking strain is. They obviously do allow a fair margin, not so much for our safety, but to avoid their own liability issues.
Good luck!
Samthehorse
ArboristSite Lurker
That'll teach me to reply without reading all the messages!
John Paul Sanborn
Above average climber
You learn quick
Welcome to the site!
Welcome to the site!
