Friction in rigging - May 15

At EverGreen Outdoor, we rely on friction to help control loads when lowering branches out of a tree. We wrap our rigging lines around the trunk of a tree to add friction and gain control.

One example of a friction device is called a bollard, which are posts that strap to the tree for taking wraps in a load line.

Bollards are large in diameter to help with the bend ratio. This helps lose less strength on the rigging line.

Some bollard-type lowering devices are designed with a ratcheting system that helps us remove slack from the line or lift a load.

When using rope, connecting links such as carabiners, shackles, or screw links allow us to not have to tie a knot each time we use rope.

Common shapes for carabiners are oval, D, modified D, and pear.

It is important to choose the right shape to keep the rope in the correct position in the carabiner.

We don't use these in most rigging operations including trunk and top removal operations because it could be considered a weak link in a rigging system. But we do use them in climbing! We at Evergreen Outdoor avoid connecting multiple links together for a tree trim or tree removal operation.

We also prefer using steel carabiners over aluminum because of their strength and durability.

There are a few different kinds of rope variations we will use when we come out for a tree trim or tree removal. 

Through knotting or splicing, rope can be made into any number of tools to help us with your job.

Webbing slings come in differently sized sewn loops, or they can be knotted from tubular webbing. The strength of the sling depends on the material, if the loop is sewn or knotted, and the way the loop is used.