The included angle of a multileg sling should not exceed how many degrees?

• A. 100 degrees
• B. 120 degrees
• C. 140 degrees
• D. 90 degrees

Answer: (B)

In a multileg sling, how the legs share the load depends on the included angle between them. The larger that angle, the more each leg must carry, so the sling’s effective capacity drops as the angle grows.

For two legs symmetrically supporting a load, the included angle is θ. Each leg forms an angle θ/2 with the vertical, so the vertical component of each leg’s tension is T cos(θ/2). Together they support the load W: 2T cos(θ/2) = W, which gives T = W / (2 cos(θ/2)). As θ increases, cos(θ/2) decreases, making T larger. At θ = 120 degrees, T = W / (2 cos 60°) = W, which is the practical limit for many slings before the capacity is exceeded.

So the included angle should not exceed 120 degrees. Smaller angles increase capacity, but larger angles demand more tension per leg, risking overloading the sling.