Lifting equipment failure: Objects dropped into moonpool

The incident occurred when crew were moving moonpool carriages and frames into position during mobilisation of multibeam echosounder equipment through the moonpool. The moonpool carriage was successfully positioned.

As the crew lowered the second moonpool frame into position, the chain on the hoist crane suddenly parted and the frame and carriage fell into the moonpool damaging one of the stopper bars on the wall of the moonpool before being stopped by the other stopper bars.

There were no injuries. There was some damage to the stopper bars and brackets.

Our member’s investigation noted the following:

• Before starting the job, all personnel involved took part in a toolbox meeting and job safety analysis (JSA). A permit to work had been granted.
  
  
• The first lift, using the crane in remote control mode, was successful.
  
  
• The hoist crane had a safe working load (SWL) of 5 tons.
  
  
• The immediate cause of the incident was found to be that during the lifting of the frame, it was obstructed by one of the bracket stoppers.
  
  
• The underlying cause was stress and subsequent failure of the chain of the hoisting crane.
  
  
• The root causes were:
  • Lack of specific procedure regarding lifting a moonpool frame.
  • Lack of awareness from crew who handled lifting moonpool frames to ensure smooth process during lifting.