Subsea Spool Tie-In Incident

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

What Happened

• Divers were working on the seabed in poor visibility during subsea spool tie-in operations.
• After landing the pipe handling frame (PHF), the Diving Supervisor ordered the crane operator to lower the crane hook to the seabed to disconnect rigging.
• The crane operator reported no weight on the crane wire, and the Diving Supervisor assumed the hook was on the seabed.
• The supervisor instructed the diver to disconnect the PHF from the crane.
• While the diver was disconnecting the rigging beneath the PHF, the crane hook hit the diver's helmet.
• The diver was uninjured and immediately returned to the dive bell, and the dive was aborted.
• The diver's reclaim helmet was damaged beyond repair upon later inspection
• The helmet's integrity was maintained, proving the diving helmets' durability.

What Went Right

• Diver 2 assisted Diver 1, confirming no injuries.
• Both divers returned to the bell safely.
• Divers and the crane block had locating beacons for accurate tracking.
• Procedures, lifting plans, and Job Hazard Analysis (JHA's) were followed.
• Protective equipment worked, and the diver was uninjured due to the helmet absorbing the impact.

What Went Wrong

• When lowered for PHF rigging disconnection, the crane hook rested on the PHF's top beam resulting in a 'no weight' reading.
• It led the crane operator to assume the hook was on the seabed.
• As the diver approached the disconnection point, the hook slipped off the beam and hit the side of the diver's helmet.

What Was the Cause

• The crane pennant/stinger was an inadequate length and didn't provide enough distance between the divers and the crane hook.
• Poor-visibility hindered the ability to accurately observe the position of the crane hook.

Lessons and Actions

• Ensure adequate distance between divers and crane hook: Use a sufficiently sized crane pennant/stinger to maintain a safe distance between the divers and the crane hook, especially in limited visibility.
• Enhanced visibility aids and monitoring: Use alternative methods such as additional locating beacons, underwater cameras, or sonar in low-visibility environments to better track the crane hook's position.
• Reinforce communications, challenge assumptions: Minimize assumptions about equipment position.
• Clear communication and confirmation procedures between the dive supervisor, crane operator, and divers should be reinforced to ensure all parties are fully aware of the equipment's location at all times.
• Updated project procedures to specify minimum pennant lengths for different operations.
• Conducted pre-operation inspections of all rigging and lifting equipment including crane hooks and pennants, to ensure they meet safety standards.
• Updated the Job Hazard Analysis (JHA) to incorporate lessons learned regarding safe distances, visibility, and communication requirements for subsea lifting operations.