Lost time injury (LTI): Deadman anchor (DMA) toppled over, injuring a diver

The incident occurred whilst a diving support vessel (DSV) was working on preparation to install a closing spool. Three DMAs were being deployed to use static and mechanical hold backs attached to the spool. Two DMAs were deployed by the DSV. The third had been previously deployed and wet stored by a 3rd party vessel. The DSV had no involvement in the deployment to the seabed of this third Deadman anchor (DMA3), but upon arriving on site found it to be placed in the correct location and decided to use it rather than deploy the DMA identified on the approved dive plan.

Holdbacks were attached to DMA3 and as Diver 2 took up the slack in the rigging, it toppled over, trapping the diver on the seabed by his left leg. Diver 1 went to his assistance and helped free him.

Both divers made their way safely back to the bell and were recovered to surface. After decompression, diver 2 was flown ashore to hospital and was diagnosed with a fracture of the fibula and a torn ankle ligament. The diver has since made a full recovery and is expected to return to his normal work activities.

• DMA3 that toppled over (blue DMA image above) was different in weight and design from the one required in company procedures.
  
  
• DMA3 had a very narrow footprint and tall body with a high centre of gravity, making it unstable and unsuitable for rigging under tension and deploying in an upright position.
  
  
• The dive plan identified deployment of a 10te DMA (yellow DMA image above). However, the team decided to use the one deployed by the 3^rd party vessel.
  
  
• Whilst this was convenient, no check was made to ascertain whether or not it was fit for purpose.
  
  
• No management of change (MoC) process was initiated, and the risk of this DMA toppling was not identified.

The root cause identified was that the risk management process for the use of DMA3 was not effectively utilised and the work team risk perception on this occasion was poor.

Our Member suggested that the following things went wrong:

• Existing procedures and risk assessments for the use of subsea DMAs were too generic.
  
  
• There was a ‘change’ which introduced an increased risk. However, the level of risk presented by the use of DMA3 was not adequately assessed and was perceived as being low.
  
  
• DMA3 was procured and sent offshore [by others] for another task. It was identified subsequently that DMA3 was in fact a crane counterweight and was not the most suitable piece of equipment for the task it was being used for.
  
  
• The lifting points on DMA3 were located on the top of the weight and it could only be deployed in the vertical position, offering a small footprint and high centre of gravity.
  
  
• The rigging arrangement placed the diver in close proximity to DMA3 during attachment, adjustment and detachment.
  
  
• There was a level of complacency within the offshore team – the hazards associated with the non-standard DMA3 were not immediately recognised and therefore not considered.