Subsea Spool Tie-In Incident

• During subsea spool tie-in operations, a diver's helmet was struck by a crane hook

What Happened

• Divers were working on the seabed in poor visibility during subsea spool tie-in operations
• After the pipe handling frame (PHF) landed, the Diving Supervisor told the crane operator to lower the crane hook to the seabed to disconnect rigging
• The crane operator reported 'no weight' on the crane wire, so the Diving Supervisor assumed the hook was on the seabed and told the diver to disconnect the PHF
• The crane hook unexpectedly struck the diver's helmet when the diver was positioned beneath the PHF disconnecting the rigging
• The diver was unharmed and safely returned to the dive bell, then the dive was aborted
• The diver's reclaim helmet was damaged beyond repair, including the side block, but the helmet's integrity was maintained
• The diver was unharmed

What Went Right

• Diver 2 helped Diver 1, ensuring that no injuries occurred
• Both divers returned to the bell safely immediately
• Both divers and the crane block had locating beacons for accurate tracking
• All procedures, lifting plans and Job Hazard Analysis (JHA's) were followed
• Protective equipment worked, because the diver was uninjured because the impact was absorbed by the helmet

What Went Wrong

• When the crane hook was lowered for PHF rigging disconnection, it rested on the top beam of the PHF, resulting in a 'no weight' reading and operator assumption the hook touched the seabed
• When the diver approached the disconnection point, the hook slipped off the beam and struck the side of the diver's helmet

Causes

• Inadequate crane pennant or stinger length failed to provide sufficient distance between the divers and the crane hook
• Poor visibility hindered the ability to accurately observe the crane hook

Lessons and Actions

• Ensure adequate distance between divers and crane hook by using a long enough crane pennant/stinger to maintain a safe distance
• Enhanced visibility aids and monitoring should be used such as additional locating beacons, underwater cameras, or sonar
• Reinforce communications, challenge assumptions to minimize assumptions regarding equipment position
• Clear communication and confirmation procedures between the dive supervisor, crane operator, and divers should be reinforced
• Member companies should update project procedures to specify minimum pennant lengths for different operations
• Conduct pre-operation inspections of all rigging and lifting equipment, including crane hooks and pennants, to ensure compliance
• Update the Job Hazard Analysis (JHA) to incorporate lessons learned from this incident regarding safe distances, visibility, and communication requirements for subsea lifting operations