Using mechanical advantage in rigging makes lifting heavy loads easier. It works by multiplying the force you apply to the load line. This video shows a 4:1 pulley system that will move a load 4 feet for every 1 -foot of rope pulled through. It also shows the same system flipped around and rigged to a 5:1 mechanical advantage. For every 1 – foot of rope pulled through the load moves 5 feet. It goes by quick so you might want to rewatch to catch it.

In this demonstration, Chris Girard refers to anchoring to a GRCS to apply lift. He also uses a Hobbs II extensively in mechanical advantage rigging scenarios.

In a nutshell, a 4:1 mechanical advantage in rigging is great when you’re in limited space, but takes a little more effort to move the load. A 5:1 mechanical advantage uses more rope, but is a little easier to move the load. Chose the right mechanical advantage for your setup based on the weight of the load and how much rope-tending space you have.