Diver safety: Crane Hook Incident

Study Notes

During subsea spool tie-in operations, a diver's helmet was struck by a crane hook.
This safety flash was published and generated on March 6, 2025, as IMCA SF 04/25.

Divers were working on the seabed with poor visibility during subsea spool tie-in operations.
After landing the pipe handling frame (PHF), the Diving Supervisor told the crane operator to lower the crane hook to the seabed for rigging disconnection.
The crane operator reported 'no weight' on the crane wire.
The Diving Supervisor assumed the hook had reached the seabed and instructed the diver to proceed with disconnecting the PHF.
While the diver was positioned beneath the PHF, the crane hook unexpectedly struck the diver's helmet.
The diver reported being unharmed and immediately returned to the dive bell, aborting the dive.
Inspection revealed the diver's reclaim helmet was damaged beyond repair, including the side block.
The helmet's integrity was maintained despite the impact, proving the high quality and durability of diving helmets; the diver unharmed.

Diver 2 promptly assisted Diver 1, preventing injuries and ensuring both divers returned to the bell safely.
Both divers and the crane block had locating beacons for accurate tracking.
All procedures, lifting plans, and Job Hazard Analysis (JHA's) were followed during the operation.
Protective equipment absorbed the impact, preventing injury to the diver.

The crane hook came to rest on the top beam of the PHF, resulting in a 'no weight' reading and causing the crane operator to assume it had reached the seabed.
When the diver approached the disconnection point, the hook slipped and struck the side of the diver's helmet.

The crane pennant/stinger was not long enough, failing to provide enough distance between the divers and the crane hook.
Poor visibility hindered the ability to accurately see the position of the crane hook.

Ensure there is enough distance between divers and crane hook by using a sufficiently long crane pennant/stinger during subsea operations to reduce the risk of accidental contact, especially in limited visibility conditions.
Use enhanced visibility aids and monitoring, such as additional locating beacons, underwater cameras, or sonar, to track the position of critical equipment like the crane hook in environments with poor visibility to prevent miscalculations.
Reinforce communications and challenge assumptions, minimizing assumptions regarding equipment position.
The dive supervisor, crane operator, and divers should reinforce clear communication and confirmation procedures to ensure all parties are fully aware of the equipment's location.

Project procedures were updated to specify minimum pennant lengths for different operations.
Pre-operation inspections of all rigging and lifting equipment, including crane hooks and pennants, were conducted to ensure they meet safety standards and are appropriate for the operation.
The Job Hazard Analysis (JHA) was updated to incorporate lessons learned from this incident, particularly regarding safe distances, visibility, and communication requirements for subsea lifting operations.