The Bureau of Safety and Environmental Enforcement (BSEE) has issued a safety alert regarding an incident of umbilical termination failure that led to dropped remotely operated vehicle (ROV).
According to BSEE, the incident occurred at a Gulf of America facility involving a remotely operated vehicle (ROV) that dropped into the water and descended to the seafloor.
The ROV operator had completed an inspection dive of the drilling riser and Blow Out Preventer (BOP) and was in the process of recovering the unit from the water. After the ROV was nested in the Launch and Recovery System (LARS) cursor, it cleared the surface and traveled along the vessel cursor rails to the transition point.
At this point, the operator stopped hauling in the umbilical winch and cursor assist tuggers to switch the umbilical winch to low-tension mode. As the ROV reached the cursor rail transition point, the umbilical parted, causing the ROV to fall to the seafloor.
The ROV was later located and recovered using its transponder. No damage to seabed assets or harm to personnel occurred.
Cause
The incident was traced to a flaw in the initial umbilical attachment. A resin was used to secure the umbilical to the ROV, but the resin case was faulty, and the armored strands were improperly centered and distributed during the attachment process.
Despite passing a previous pull test, these defects led to the failure.
Lessons learned:
- Develop and implement an umbilical termination inspection procedure and training program to ensure proper inspection of resin condition and the assessment of armored strand separation. The program should also include training on re-termination of umbilicals.
- Incorporate umbilical inspections into pre-job checks and maintenance procedures to ensure the integrity of the connection is verified prior to use.
