From static PDF to dynamic data—secure, validate, and share rigging calculations in real-time.
Working Load Limit (WLL) vs. Minimum Breaking Strength (MBS)
To demonstrate the value of these documents, let us walk through a typical problem found in any advanced rigging PDF.
Safety Warning: Never use a horizontal sling angle of less than 30 degrees. At shallow angles, the tension skyrockets exponentially, creating severe risks of rigging failure. 2. Center of Gravity (CG) and Asymmetric Load Distribution From static PDF to dynamic data—secure, validate, and
A: Look for resources created by established organizations like Crosby , Columbus McKinnon , ITI , or academic institutions. Be wary of unofficial scans that may have missing pages, errors, or be outdated. The "extra quality" often lies in the authority of the source.
A crane’s load chart does not represent the net weight the crane can lift off the ground. It represents the gross capacity at a specific radius. To determine the Net Capacity (the actual maximum weight of the payload), engineers must subtract all "deductions" from the Gross Capacity:
Tension(T)=Load(W)Number of Slings×sin(θ)Tension open paren cap T close paren equals the fraction with numerator Load open paren cap W close paren and denominator Number of Slings cross sine open paren theta close paren end-fraction Where θ is the angle between the sling and the horizontal. B. Center of Gravity (CG) Determination Safety Warning: Never use a horizontal sling angle
The Occupational Safety and Health Administration offers free online manuals detailing basic hitches, load capacities, and inspection criteria.
To calculate the center of gravity along a linear axis with multiple components, use the moment formula:
: A comprehensive reference for professional riggers that includes formulas for sling angles ( ), center of gravity ( Center of Gravity (CG) and Asymmetric Load Distribution
Weight on Point 1=Total Weight×d2d1+d2Weight on Point 1 equals Total Weight cross the fraction with numerator d sub 2 and denominator d sub 1 plus d sub 2 end-fraction
The tension on a sling increases drastically as the horizontal sling angle decreases. When lifting a load with multiple legs, engineers use the sling angle factor (SAF) to determine the actual force exerted on each sling:
To download the free PDF guide to rigging engineering calculations, simply click on the link below:
Verification that shackles and links match or exceed the worst-case sling tensions.