201929 Incomplete re-assembly causes serious injury

26 Apr 2019 MARS 2019

While at sea, two deck crew were occupied with the maintenance of the emergency towing arrangement (ETA). This job was routine maintenance and was described in the company’s job-specific procedure for the ETA. The crew were new to this task, which included the lubrication of the ETA, the dismounting and maintenance of the airdriven motor and, as a last step, the operational test of the motor in its mounted position.

Before work started, the job was discussed and recorded via a toolbox talk. The two crew reviewed a risk assessment. However, this assessment covered only the lubrication aspect of the work and not the testing of the motor.

The motor, which weighed about 50kg, was dismounted and transferred to the engine room for lubrication and maintenance. Once completed, the motor was brought back on deck and re-installed using the three mounting bolts. The bolts were inserted but, for reasons unknown, were not tightened up completely.

The air supply valve of the motor had been closed and properly tagged during the maintenance, but now the valve was reopened to proceed with the test. As the air pressure turned the motor a strong torque developed and the motor began vibrating rapidly and unequally due to the unsecured bolts. The motor quickly came away from its mounting and struck the two crew members. Both were injured severely enough to require shore treatment and repatriation.

 

Lessons learned

  • Humans are fallible and a slip, lapse or mistake can happen. Always review and cross-check your work before testing a newly installed or maintained piece of machinery.
  • Risk assessments should be completed for all aspects of a job and safeguards established against all identified risks.

Editor’s note:

For our readers’ information, please see the following definitions: Slip, an unintentional action where the failure involves attention (or lack of attention). Lapse, an unintentional action where the failure involves memory. Mistake, an intentional action where there is an error in the planning process but no deliberate decision to act against a rule or procedure.