Which type of pulleys are not designed to move within a haul system?

Directional pulleys are specifically designed to change the direction of the force being applied to a rope or cable but are not intended to move as part of the haul system itself. They serve the purpose of guiding the rope, allowing for a more efficient application of force, but do not alter their position within the setup.

In contrast, fixed pulleys remain stationary and are attached to a structure, allowing movement of the load vertically or horizontally as the rope is pulled. Adjustable pulleys can change position within the haul system, thereby modifying the mechanical advantage gained. Movable pulleys, on the other hand, can shift their position as the load moves, contributing to the lifting or maneuvering of the load being handled.

Thus, the characteristic of directional pulleys as non-moving components in a haul system highlights their unique role in assisting with the direction of the applied force without being part of the actual lifting mechanism.