What is the rope used by the operator to move the purchase of the load, often in systems with mechanical advantage?

• A. Rope lock
• B. Purchase line
• C. Screw-pin shackle
• D. Turnbuckle

Answer: (B)

The main idea here is understanding rigging terminology for systems with multiple pulleys and mechanical advantage. In such systems, the portion of rope that actually creates the movement of the load’s moving block is called the purchase line. This line works as the part of the rope that “purchases” the motion—through the pulley assembly, the operator’s action on the haul line (the line you pull) translates into movement of the purchase, allowing the load to rise with less effort. The other terms refer to different things: a rope lock is a device to hold rope from slipping, not the moving rope itself; a screw-pin shackle and a turnbuckle are hardware fittings used to connect or tension components, not the rope responsible for moving the load. So the rope used to move the purchase of the load is the purchase line.