In a RIT Class I was taught how to make a 3:1 mechanical advantage system using three extra large carabiners and my personal escape rope.  You have a figure 8 with one carabiner to the victim, and a few feet behind the figure 8, away from the victime, a butterfly is made.  The rope works its way up to an anchor with the second carabiner.  The rope runs through this second carabiner, your anchor, and then the ropre runs through the third carabiner attached to the butterfly.  I'll try and get…