Mastering Load Centre of Gravity (COG): The Key to Safe and Efficient Lifting

Understanding the centre of gravity (COG) of a load is crucial for executing safe, stable and efficient lifting operations. Ignoring this principle can result in load instability, tilting, unbalanced tension on slings, and even tipping or catastrophic failure. This week’s tip dives deep into the importance of identifying and managing the COG correctly and offers best practices to elevate your rigging expertise.

What is the Centre of Gravity?

The centre of gravity is the exact point at which the entire weight of an object can be considered to act. In simple terms, it’s the balance point. If supported at this point, the load will remain perfectly level. Misjudging it during lifting operations may cause the load to tilt dangerously or shift mid-air.

For symmetrical objects with uniform mass, the COG is typically at the geometric centre. However, most real-world loads are asymmetrical or contain dense internal components that shift the COG off-centre — and that’s where the danger lies.

Why is it Critical in Rigging?

  • Improper estimation of the COG can cause the load to tilt during lifting.

  • Unequal sling angles lead to excessive stress on one side, risking sling failure.

  • A swinging or rotating load makes it harder for riggers and operators to maintain control.

  • In extreme cases, the load could slip out of the rigging or cause crane overload.

The result? Equipment damage, potential injuries, or halted operations.

How to Determine the Centre of Gravity

  • Start with Documentation:
    Always check the load’s design drawings or specifications, especially for machinery or prefabricated units.

  • Visual Assessment:
    Consider the shape and likely internal mass distribution. Heavy machinery, for instance, often has motors or gearboxes that shift the COG off-centre.

  • Use Test Lifts:
    Gently tension the slings and lift a few centimetres off the ground. Observe the tilt and correct accordingly before lifting further.

  • Use of Load Cells and Electronic COG Indicators:
    Advanced rigging projects may use digital tools to pinpoint the COG precisely.

  • Correct Sling Configuration:
    Adjust sling lengths or lifting points until the load remains horizontal when slightly raised.

Best Practices

  • Always assume the load is unbalanced until proven otherwise.
  • Use adjustable slings or spreader beams to help balance irregular loads.
  • Mark the COG on loads that are frequently handled.
  • Brief your rigging team — especially during multi-point lifts — on the expected COG and strategy.
  • Never improvise. Proper planning is always safer and faster in the long run.

Real-Life Example

During the lifting of a generator, a team used equal-length slings from two top eye bolts assuming symmetry. Once lifted, the generator tilted dramatically — one side had a denser internal diesel motor. Fortunately, it was a controlled test lift, and no one was harmed. Adjusting sling lengths rebalanced the load. This simple oversight, if not corrected, could have caused thousands in damage.

COG: Not Just Theory, But Core Practice

Understanding the COG is not just theory — it’s a life-saving principle. Whether you’re handling beams, machinery, containers or modular structures, respect the centre of gravity. Balance leads to control. Control leads to safety.

If you prefer

Write to us!

If you’re already sure that ELEVACADEMY is your best choice for specialized training in lifting and load securing but prefer to write to us, send an email to hello@elevacademy.com or fill out the following form if you prefer:

How to Properly Inspect Lifting Equipment for Safety and Longevity
Tag It Right: The Critical Role of Load Identification & Labelling in Safe Rigging