Pulley of a single continuous rope to transmit a tension force around one or more pulleys to lift or move a load—the rope may be a light line or a strong cable. This system is included in the list of simple machines identified by Renaissance scientists. If the rope and pulley system does not dissipate or store energy, then its mechanical advantage is the number of parts of the rope that act on the load. This can be shown as follows. Consider the set of pulleys that form the moving block and the parts of the rope that support this block.
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