A recent IMCA Safety Flash focuses on an incident in which a lift bag while being inflated, ascended through the engineered rigging arrangement and was caught by the contingency rigging, during the over-boarding of a spool, to provide lessons learned.
The diver had rigged the lift bag inappropriately for the conditions. The lift bag was hooked into one eye of the sling, the sling then slipped out as the lift bag became inflated and was inverted with the safety strap. Our member considered this incident to have had the potential for a serious injury or fatality.
What went wrong
- Assumptions were made by the diver and by the supervisor, about the rigging, perhaps owing to:
- Poor visibility.
- Diver inexperience with lift bag operations.
- Complacency.
- The rigging arrangements were not correct nor verified as per procedure:
- Spool rigging and local in-field adjustment began to happen without proper documentation or formal management of change (MoC).
- The divers were multi-tasking, working in different locations on different concurrent tasks, and communications between the divers and diver supervisor were complex and unclear.
- The rigging had been changed earlier but this change had not been communicated to the dive team.
- As the final spool was lowered, late at night, rigging changes were not noticed.
- Existing procedures were not specific to this task:
- A 4-ton lift bag was identified in the procedure but was not available.
- The inverter rigging was not one size fit all, as the bags were different sizes, thus creating a scenario where diver rigging was required to lengthen or shorten the existing rigging.
- There were changes of personnel during the job:
- Superintendents were changed out.
- The bell run was split such that the diver that de-rigged the spool was not the same diver as inflated the lift bag that came loose.
- During the job, a finger incident occurred on the bell clump basket, and there was a safety stand down.
Lessons learned
- Ensure one single person is accountable for rigging, reporting to the Superintendent and collaborating with the dive team.
- Improve management and installation of rigging configurations.
- Ensure written procedures are not generic, are up to date, and reflect the details of the task in hand.
- Minimise multitasking to eliminate distractions and fatigue.
- Be additionally vigilant and ensure there is thorough communication:
- At crew change and at shift change.
- Between shore-side or yard and vessel.
- Between crew of different departments – dive, deck, bridge, project, etc.
