Block and tackle rope through the block. The snatch block is also the load lifting pulley in certain arrangements. Block and tackle A block and tackle is a system of two or more pulleys with a rope or cable threaded between them, usually used to lift heavy loads. The pulleys are assembled together to form blocks and then blocks are paired so that one is fixed and one moves with the load. The rope is threaded through the pulleys to provide mechanical advantage that amplifies the force applied to the rope. Hero of Alexandria described cranes formed from assemblies of pulleys in the
Cargo hook (helicopter) metal at the bottom of a cargo hook that supports the load. Usually it has a curved, narrow end which is used to load a ring, rope, or net onto the hook. The keeper is the locking, spring-operated mechanism that keeps the load from sliding off the load beam during transport. The attach point attaches the hook to the belly of the helicopter, swing system, or longline. The following table includes a list of helicopter models that are designed to carry underslung loads. Cargo capacities provided reflect the airframe manufacturer's specifications; when put into practice the actual maximum load capacities