On January 8, 2024, a dry bulk carrier broke free from its moorings at a dock in the Brownsville Ship Channel, Texas, during high winds. The incident, investigated by the National Transportation Safety Board (NTSB), resulted in multiple vessel collisions and structural damage, though no injuries or pollution were reported.
What Happened
That morning, the vessel was moored port side to the pier at dock no. 12 for cargo discharge. It was initially secured with ten polypropylene mooring lines. As wind speeds increased throughout the morning, reaching approximately 50–55 knots by early afternoon, the vessel’s crew deployed additional lines, increasing the total to sixteen.
Around 12:35 local time, high lateral wind force acting on the vessel’s increased sail area caused several forward mooring lines to part. This initiated a cascading failure of the remaining lines and two dockside bollards. Despite efforts to anchor, the vessel drifted across the 800-foot-wide channel and collided with a moored tugboat on the opposite pier. The impact led to a chain reaction of collisions involving two additional tugboats and the destruction of the pier infrastructure. Additionally, propeller wash from one of the tugs capsized a small harbor police boat and damaged its dock.
Why It Happened
The probable cause was the wind force acting on the vessel’s exposed freeboard, which exceeded the breaking strength of the mooring lines. The vessel’s increasing freeboard due to offloading cargo made it more susceptible to wind loading. Although the mooring lines were certified and in good condition during their last inspection, no post-incident testing or bollard assessments were conducted. Therefore, potential contributions from weakened or overloaded components could not be definitively ruled out.
Actions Taken
The crew deployed all available mooring lines before the breakaway. Anchors were dropped, and the vessel’s engine was started but not used due to concerns about fouling from loose lines in the water. Tugboats responded promptly to control the vessel post-collision.
Lessons Learned
- Monitor weather advisories and proactively assess mooring adequacy as wind conditions escalate.
- Consider dynamic forces acting on a vessel’s freeboard when offloading cargo in adverse weather.
- Ensure redundancy in mooring arrangements in exposed berths, especially during forecasted gales.
- Post-incident assessments of failed components (e.g., mooring lines, bollards) are critical for identifying contributing factors and preventing recurrence.
Did you subscribe to our Daily newsletter?
It’s Free! Click here to Subscribe!
Source: NTSB
