Dropped object – Crane auxiliary block dropped from crane boom

  • Safety Flash
  • Published on 8 April 2021
  • Generated on 26 December 2024
  • IMCA SF 10/21
  • 2 minute read

Two sub-contracted crane technicians were mobilised to the vessel to inspect the pipelay system 15Te crane before a load and rock test of the crane took place. 

What happened?

Following completion of the inspection, which included a function test of all equipment and interlocks, no issues were detected and the pipelay team then began preparations for the testing utilising water weight bags. 

The crane operator was instructed by the banksman, who was situated on the main deck to extend the boom so it was positioned over the basket containing the water bags, sited on the main deck. It was during the extension of the boom that the auxiliary crane wire failed and the block, weighing 30 kg dropped from crane boom to main deck (approximately 30 metres). The block landed directly into a steel container that was used for storing tensioner pads.

What was the cause?

The cause of the failure was due to the double blocking of the auxiliary block and chandelier, also the interlock overload protection failed to activate.

Screenshot 2021 04 08 084728

Lessons learned and actions

This incident is currently under investigation and further information may be available at a later time.

  • The following good practices were noted:

    • The operation was being controlled under a Permit to Work.

    • A task specific risk assessment had been developed which clearly identified potential dropped objects, the need for barriers and sentries and restricted access to the deck.

  • The following immediate improvement was identified:

    • Although a banksman was in place for this task, he was too far away to effectively monitor the full movement of the crane. An additional spotter should have been used.

  • Further discussion points:

    • Ensure crane checks are carried out daily.

    • Ensure crane operators do not rely solely on their crane limits to stop a movement.

    • The banksman should at all times direct the crane operator when the crane is on the move, from start up when removing the crane from the rest, through to until it is parked and made secure.

    • Where applicable, additional spotters should be used to monitor positions of crane blocks.

Members may wish to refer to:

Latest Safety Flashes:

Structural failure of rescue boat

A rescue boat suffered a catastrophic structural failure whilst unattended on the davit.

Read more
High potential: spontaneous opening of hydraulic release shackle (HRS) pin

During lifting operations on a vessel, a hydraulic release shackle pin opened on its own.

Read more
NTSB: diesel generator engine failure

The National Transportation Safety Board of the United States (NTSB) published "Safer Seas Digest 2023".

Read more
LTI: fall from height during anchor chain handling operation

A worker fell through an opening from one deck to another, and was injured as a result.

Read more
Sudden disconnection of pressurised hose

A contractor was performing maintenance on the bulk cargo methanol system on deck of a vessel.

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.