3:1 haul with no friction hitches
Here’s the typical method for rigging a 3:1 “Z pull”:
Put a friction hitch or rope grab of some kind (like a Petzl Tibloc) onto the load strand.
Clip your pulling strand to that to make the “Z”.
Start hauling.
Okay, pretty standard stuff.
But, what if you need to rig a 3:1 and you don't have a friction hitch or a rope grab?
Guess what? You can clip that hauling strand directly to the load.
Exact same mechanical advantage, but without any friction hitches or rope grabs. Pretty cool!
Some of you might be thinking, “Well duh, of course that's how it works.” But when I recently saw this demonstrated it was kind of an eye-opener, so I thought it might be something new for you as well.
Finally, to be sure this is a 3:1, let's do a quick run through with the “T method” (or counting tensions) to check the mechanical advantage. Check out my detailed article on the T method.
Here's how this can be useful in crevasse rescue.
You can drop a loop of rope with a carabiner or pulley on it to your victim, and have them clip it to their harness.
Then you can set up a 3:1 haul from the top.
This is the basic principle behind the drop loop 3:1 method; I have a detailed article about that here.
image: UIAA Alpine Summer Skills Handbook