The number of wraps on a capstan indicates what?

• A. The angle of the wrap
• B. The amount of force applied to the pull
• C. The speed of the pull
• D. The length of the rope wound on the capstan

Answer: (B)

When you wrap rope around a capstan, friction between the rope and the surface gives you leverage. The more you wrap, the greater that frictional grip, which changes how forces on the pull side relate to the force transmitted to the load. In practical terms, increasing the wrap increases the amount of force that can be transmitted to the rope you’re pulling for a given load, or conversely, lowers the amount of pull you need to apply to hold or move the load. That’s why the number of wraps indicates the force you can apply to the pull. More wraps mean you can apply more pulling force before slipping occurs, thanks to the friction amplified by the wrap.