Unsecured sheave pin fell from crane
- Safety Flash
- Published on 28 April 2026
- Generated on 28 April 2026
- IMCA SF 08/26
- 2 minute read
A sheave pin weighing 1.3 kg was found on deck.
What happened?
It fell from a 600 tonne crawler crane supplied by a third party. The pin likely fell from 30m height after the crane wire came into contact with its split pin, causing it to snap or to become dislodged. No-one was in the line of fire at the time, and there were no injuries. However, the incident posed a significant potential risk.
What went wrong?
- The sheave was not required for the crane’s operational configuration and was not referenced in the assembly documentation.
- Assembly instructions did not cover the sheave assembly, and securing methods were not reviewed for this configuration.
- During assembly, it had been verbally agreed to leave the sheave in a raised position, but this agreement was not documented.
- There was no secondary retention present for the pin.
Lessons to learn
- Are all components, including those not required for the current configuration, considered in assembly and operational drawings, procedures and risk assessments.
- How might changes or omissions in equipment setup lead to hazards, such as dropped objects?
- Ensure there is a written record of all configuration justifications during assembly, especially when deviating from standard procedures or manuals.
- Don’t forget the importance of additional safeguards (such as secondary retention) for pins and other parts that could become dropped objects.
- Subcontracted equipment does not mean subcontracted risk ownership – have a clear understanding of risks, roles and responsibilities when dealing with sub-contracted third-party equipment.
A causal factor in all the following incidents is that complex equipment being used was not correctly described in the drawings or documentation.
Related Safety Flashes
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IMCA SF 05/26
17 March 2026
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IMCA SF 02/26
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IMCA SF 01/26
12 January 2026
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IMCA SF 17/25
17 September 2025
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