Lightning Conductor Fell – Dropped Object Near Miss

What happened?

A lightning conductor mounted on top of a service crane came free from its mounting and dropped 75 meters.  The conductor fell through the deck carousel hatch and landed on the carousel bottom plate.  Five crew members were working in the carousel; however, they were not positioned under the open deck hatch area.

The vessel was in dry dock at the time of the incident.  There were no injuries.

   Mast and lightning conductor                Lightning conductor

What were the causes?  What went wrong?

Initial investigation has indicated:

• The mast has been vibrating during high winds causing the lightning conductor to work itself free from the threaded housing;
• There was no material failure;
• The lightning conductor was not secured to its housing by any means other than the threaded connection – no secondary securing;
• The potential for the lightening conductor to become unscrewed was not recognised;
• The connection is not easily visible during regular drops inspections;
• Equipment was not part of planned maintenance system.

What actions were taken?

• Consider the potential for a similar incident to occur on your vessels;
• Perform an inspection of all similar equipment at height and assess the secondary securing arrangements in place.

Members may wish to refer to:

• Dropped object near miss: Antenna parts worked loose and fell to deck
• Near miss: Dropped object – falling camera
• High potential dropped object near-miss: antenna fell to deck