What is the minimum number of wraps on a drum?

What is the minimum number of wraps on a drum?

• A. One
• B. Two
• C. Three
• D. Four

Answer: (B)

When winding a rope or cable on a drum, you need enough contact between the rope and the drum to generate sufficient friction so the rope doesn’t slip as load is applied or direction changes. With only one full turn around the drum, that contact is too small and the rope can begin to slip or unwind under tension, risking a drop or uncontrolled movement. Adding a second full wrap increases the contact area enough to grip the rope reliably through starting, stopping, and changes in direction, making the hoisting operation safer. Four wraps would be more than necessary for the minimum requirement and could add extra wear or complexity, while one wrap is simply not sufficient. Therefore, the minimum number of wraps is two.

When winding a rope or cable on a drum, you need enough contact between the rope and the drum to generate sufficient friction so the rope doesn’t slip as load is applied or direction changes. With only one full turn around the drum, that contact is too small and the rope can begin to slip or unwind under tension, risking a drop or uncontrolled movement. Adding a second full wrap increases the contact area enough to grip the rope reliably through starting, stopping, and changes in direction, making the hoisting operation safer. Four wraps would be more than necessary for the minimum requirement and could add extra wear or complexity, while one wrap is simply not sufficient. Therefore, the minimum number of wraps is two.