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MAIB: A heavy sheave fell over causing an LTI

What happened

A bosun suffered a broken leg when a heavy sheave he was trying to manoeuvre, fell against him. On a vessel going into port, crew were preparing to offload equipment. Very early in the morning, the bosun decided to prepare a 0.5t sheave, which was due to be lifted ashore. He removed the lashings that were securing the sheave vertically against some pipework and started to roll it toward the port side hatch in readiness for offload. The bosun was manoeuvring the sheave past some oil drums when he lost control and the sheave toppled over, struck his thigh and then trapped him under its weight. With difficulty he managed to raise the alarm using his handheld radio. The crew mustered quickly, lifted the sheave off his leg and administered first aid. Once in port the bosun was taken to hospital with multiple fractures to his leg and was unable to return to work for several months.

What went wrong

  • The bosun worked alone;
  • The sheave, half a ton and over 1m in diameter was not stowed in an authorised location;
  • The crew had no lifting plan in place to move it across the space. The sheave was unwieldy and careful planning and thought would have been required before it could be moved safely, despite it being easy to roll;
  • The bosun was unaware of the weight of the sheave and had underestimated the risks and hazards involved in both its removal and relocation.


  • Don’t just “crack on” with a task rather than bother other people to get help – STOP and THINK;
  • Have a clear, communicated and fully understood plan for moving an object of this size and weight.

Members may wish to refer to

Safety Event

Published: 12 June 2023
Download: IMCA SF 14/23

Relevant life-saving rules:
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