Quote:
Originally Posted by George Hayduke  Before you walk away from that comment you need to elaborate. This isn't true.
The load on the rigging point will double even with natural crotches. Adding a block displaces friction but it doesn't change the load.
In GM's rigging he would wrap the down rope around the tree which displaces the friction, and the load, somewhat. It's too simplistic to say that the trunk wrapping eliminates the load...not actually true. |
Good point, maybe we need to expand on some techniques and variables.
In natural crotch rigging you will always have friction where the rope runs over the crotch. You'll know how much and how bad when you try to pull a load back up.
If you are wrapping up top as in this diagram always wrap from the top down or the branch outwards then toward the trunk. This will prevent the loaded line cinching the lowering rope and holding the load up.
When lowering in this fashion you will not be doubling the load at the rigging point, other than the initial dynamic shock if taking a head out etc once the load is fully braked and stopped the force on the tree is 1:1 or slightly higher depending on the wraps obviously. Here's where it gets interesting, if you are up in the tree and grab the lowering rope and lock it off up there or lower from up there then the force is a lot closer to if not exactly 1:1
However if the load was braked and held up (still, stopped etc) through a block it would be 2:1
And if it were through a suspended false crotch like Quercus says then it would be 4:1