When attaching spreaders to any load, you must keep in mind that

When attaching spreaders to any load, you must keep in mind that

• A. The higher the spreader angle, the greater the tension
• B. The lower the spreader angle, the lesser the tension
• C. The higher the spreader angle, the tension will remain the same
• D. The lower the spreader angle, the greater the tension

Answer: (D)

The spreader angle determines how the load is shared between the sling legs. When the legs form a small angle with the horizontal, the vertical support each leg can contribute is reduced, so the crane must pull harder along each leg to hold up the same weight. Mathematically, for two equal legs, the weight W is the sum of the vertical components: 2 T sin(alpha) = W, where alpha is the angle of each leg from the horizontal. Solving gives T = W/(2 sin(alpha)). As alpha decreases, sin(alpha) decreases, so T increases. Therefore, the lower the spreader angle, the greater the tension. This is why wider spread reduces tension and why overly shallow angles can push sling tension beyond its rating.

The spreader angle determines how the load is shared between the sling legs. When the legs form a small angle with the horizontal, the vertical support each leg can contribute is reduced, so the crane must pull harder along each leg to hold up the same weight. Mathematically, for two equal legs, the weight W is the sum of the vertical components: 2 T sin(alpha) = W, where alpha is the angle of each leg from the horizontal. Solving gives T = W/(2 sin(alpha)). As alpha decreases, sin(alpha) decreases, so T increases. Therefore, the lower the spreader angle, the greater the tension. This is why wider spread reduces tension and why overly shallow angles can push sling tension beyond its rating.