Subsea Spool Tie-In Incident

• During subsea spool tie-in operations, a crane hook struck a diver's helmet unexpectedly.
• The incident occurred during subsea spool tie-in operations in conditions of poor visibility.
• The diver was unharmed, but the helmet was damaged beyond repair, including the side block.

Sequence of events

• After landing the pipe handling frame (PHF) on the seabed, the Diving Supervisor instructed the crane operator to lower the crane hook to allow the diver to disconnect rigging.
• The crane operator reported "no weight" on the crane wire.
• The Diving Supervisor assumed the hook reached the seabed.
• The supervisor instructed the diver to disconnect the PHF from the crane.
• While positioned beneath the PHF, the crane hook struck the diver's helmet.

Positive Outcomes

• Diver 2 assisted Diver 1 promptly to ensure no injuries occurred.
• Both divers returned to the bell safely.
• Divers and the crane block had locating beacons.
• All procedures, lifting plans, and Job Hazard Analysis (JHA's) were followed.
• Protective equipment prevented injury due to impact absorption.

Negative Outcomes

• The crane landed on top beam of the PHF, resulting in a 'no weight' reading.
• This outcome caused the crane operator to assume the hook had reached the seabed.
• The hook slipped off the beam and struck the side of the diver's helmet.

Causes of the incident

• The crane pennant/stinger's length was inadequate and did not provide enough distance between the divers and the crane hook.
• Visibility was poor, hindering accurate observation of the crane hook's position.

Lessons and Actions

• Ensure adequate distance between divers and crane hook: The crane pennant/stinger should be long enough for safe distance.
  • Improves safety in particularly limited visibility conditions.
• Improve visibility aids and monitoring: Use alternate methods in conditions of poor visibility.
  • Alternative methods could include extra locating beacons, underwater cameras or sonar to improve tracking
  • This can help prevent misjudgments regarding the location of the crane hook.
• Reinforce communications, challenge assumptions: Assumptions regarding equipment position should be minimised.
  • Should reinforce clear communication and confirmation procedures to ensure all parties are fully aware of the equipment's location at all times.
• 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 they meet safety standards and are appropriate for the operation;
• Update the Job Hazard Analysis (JHA) to incorporate lessons learned from this incident, particularly regarding safe distances, visibility, and communication requirements for subsea lifting operations.