A load chart tells you what a crane can lift in a specific configuration. Misreading it is one of the fastest routes to an overturn or structural failure.
Start with the configuration
Charts are only valid for the configuration they describe: counterweight, outrigger extension, boom length and whether a jib is fitted. Confirm every item matches the crane as it is set up.
Radius is measured, not estimated
Radius is the horizontal distance from the centre of rotation to the centre of the hook. Measure it, and remember that radius increases as the boom deflects under load.
Account for everything below the boom tip
The chart capacity must cover the load plus the hook block, slings, shackles, spreader beams and any other lifting accessories. Deductions for stowed or erected jibs may also apply.
Know the limiting factor
- Structural limits usually govern at short radius.
- Stability limits usually govern at long radius.
- Never rely on the machine’s indicator alone; it supports judgement but does not replace planning.
Load-chart interpretation is practised step by step in ILEES mobile crane and lift-planning courses until it becomes second nature.
