Near miss: Winch wire snagged and released suddenly

  • Safety Flash
  • Published on 20 March 2019
  • Generated on 27 November 2024
  • IMCA SF 05/19
  • 2 minute read

During drilling operations on a land-based drilling rig, the thimble within the hard eye of the winch wire momentarily caught (snagged) on the edge of the drill rig chassis.  It then released in an uncontrolled manner very close to the driller. 

What happened?

The incident occurred when the driller found it necessary to raise the drill mast, resulting in the winch wire being pulled upwards.  As the winch wire was pulled up, the thimble caught on the edge of the drill rig chassis.

The driller failed to notice that the winch wire had become snagged and continued to raise the mast, thus continuing to increase the tension in the wire until the steel thimble bent, causing the wire and attached hoist plug to release in an uncontrolled manner.

The incident occurred when the driller found it necessary to raise the drill mast, resulting in the winch wire being pulled upwards

The sudden and uncontrolled release of the winch wire and the attached hoist plug had the potential to cause significant personal injuries had it struck a member of the drill crew.

What were the causes?

  • Failure to identify and recognise snagging hazard.

  • Incipient complacency in what was seen as a ‘routine’ task.

What lessons were learned?

  • Investigate engineering/practical solution: retract the winch wire to a safe position when not in use; where this is not possible, lower the winch wire to a safe location away from all structures and other potential snagging hazards. Keep contained within a trip tray or bucket to prevent a tripping hazard.

  • Highlight the importance of managing all lifting operations, including winch operations and awareness of complacency creeping into routine tasks.

  • Review procedures and task risk assessments to ensure that the potential for lifting equipment (winch wires) becoming snagged is appropriately considered and mitigated. All control measures should be included.

  • Careful check of potential snagging hazards before operation of the winch or the lowering/raising of the drill mast.

Members may wish to refer to:

  • Guidelines for lifting operations (IMCA HSS019)

Latest Safety Flashes:

Diver exposed to unplanned release of production gas

A diver was exposed to a sudden and unplanned release of hydrocarbon gas under pressure.

Read more
Dropped object – wooden packing block

Dropped object – wooden packing block

Read more
BSEE: person fell through open hatch

BSEE: person fell through open hatch

Read more
Snagging hazards

Snagging hazards

Read more
Main Crane failure during load test

At maximum load, the crane main block wires broke and the testing load fell, along with the main block, into the water.

Read more

IMCA Safety Flashes summarise key safety matters and incidents, allowing lessons to be more easily learnt for the benefit of the entire offshore industry.

The effectiveness of the IMCA Safety Flash system depends on the industry sharing information and so avoiding repeat incidents. Incidents are classified according to IOGP's Life Saving Rules.

All information is anonymised or sanitised, as appropriate, and warnings for graphic content included where possible.

IMCA makes every effort to ensure both the accuracy and reliability of the information shared, but is not be liable for any guidance and/or recommendation and/or statement herein contained.

The information contained in this document does not fulfil or replace any individual's or Member's legal, regulatory or other duties or obligations in respect of their operations. Individuals and Members remain solely responsible for the safe, lawful and proper conduct of their operations.

Share your safety incidents with IMCA online. Sign-up to receive Safety Flashes straight to your email.