Inside 9 // CMC Pro Tip
In this CMC Pro Tip video, CMC School Instructors demonstrate how to build the Inside 9, a complex piggyback hauling system. The rigging flexibility provided by an Inside 9 is adaptable to many different rescue scenarios and is a great tool in the toolbox.
There are times when traditional mechanical advantage systems won’t work for a variety of reasons. An Inside 9 can be a quick, effective solution. The Inside 9 is essentially a complex piggyback hauling system. By complex, we do not mean complicated, but are instead referring to it’s mechanical advantage classification ie: simple, compound, and complex. It is designated as a piggyback system because a second rope and pulley system is piggybacked or ganged onto the mainline.
The piggyback system can be an AZTEK, as illustrated in this video; a pre-rigged 4:1, such as a CSR pulley system; or built from scratch. The 4:1 can be attached to the mainline so that the hauler(s) are pulling towards or away from the anchor. You will see using the T-Method that there are 5 units of tension on one end of the 4:1 and 4 units from the other end. When combined at the haul prusik on the mainline, you have a 9:1 mechanical advantage. The rigging flexibility provided by an Inside 9 is adaptable to many different rescue scenarios and is a great tool in the toolbox.