As a rule of thumb, what percentage is the friction loss for each sheave approximately of the sheave load?

• A. 5%
• B. 15%
• C. 10%
• D. 20%

Answer: (C)

The friction loss for each sheave is approximately estimated at 10% of the sheave load. This percentage is derived from practical experience in rigging and lifting operations, where it is crucial to account for the friction that occurs as the load moves over the sheave. This 10% figure provides a reliable guideline for crews when calculating the total force needed to lift a given load, ensuring they take into account the additional effort required to overcome friction.

This estimation aids in the effective planning and execution of lifting operations, as it helps in determining the necessary equipment specifications and load limits. Understanding this principle is vital for both safety and efficiency in the field, as underestimating the friction loss could result in insufficient lifting capacity and potentially dangerous situations.