A floodlight fell from its position on the knuckle boom of the vessel’s crane. The floodlight arrangement was supported on a stainless steel bracket, comprising a bar and attachment plate that is bolted to the knuckle boom head. This arrangement allowed the floodlight to swivel and illuminate the load area.
What went wrong? What were the causes?
The weld between the bar and the attachment plate failed due to the poor quality of the weld, which upon inspection revealed undercut, poor penetration and overdressing, resulting in a minimal fusion area which was insufficient to withstand vibration and exposure in the marine environment.
The underlying causes were found to be:
- Inadequate engineering;
- Inadequate QC/monitoring of design and build at point of fabrication (crane manufacturer).
What actions were taken?
The floodlight was restored to its original position, with a security chain installed as a retrofit attachment.
Members may wish to review the following:
- Serious dropped object incidents [arising from corrosion]
- Crane boom dropped object [failure of tack weld]
- Galvanic corrosion causes dropped object – satellite dome fell from mast
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