Equipment Damage: Dropped Object from tiltable lay system

What happened A bracket weighing 10.5kg fell 16m to deck. The incident occurred during a function test of a tensioner on a pipelay system. The tensioner doors had to be moved into the firing line, closed, and then retracted to the parked position.

As the tensioner doors were being closed, the port side door made contact with a hinged bracket that was part of an inspection manhole gate which had been left open. This resulted in the bracket, weighing 10.5 kg, dropping approximately 16m to the work table below.

What went right

Robust and stringent controls, restricting personnel from entering the drop zone, reduced the potential for harm. These included hard barriers at deck level directly underneath the work area, and additional temporary barriers to create a wider exclusion zone to take into consideration the dropped object cone of exposure. No personnel were in the line of fire at the time of the incident.

What went wrong – what were the underlying causes?

• Before this event, the inspection manhole gate had been damaged in a previous unreported incident. Subsequently some minor repair work had been undertaken which involved the removal of the grating from the gate/bracket. The hinged bracket was seized in the upright position and at the time it was not considered a dropped object hazard due to it being firmly secured to the TLS structure.
  • The seized bracket was not fully repaired following the original incident;
  • The latent hazard posed by seized bracket was not identified as a potential DROPS or as a clashing hazard.

Learning

• Although the first incident was recorded within the pipelay team handover notes, there was a failure to formally report it within the company incident reporting system – all damage incidents should be reported to ensure the correct level of investigation, and so that corrective and preventative actions are identified and implemented;
• The equipment design and layout failed to identify the clash points created when manhole gates were left in the open position.

Members may wish to refer to:

• Crane contact with pipelay tower resulting in dropped object
• Equipment on quay damaged when vessel started listing