Bulk carrier Sirocco after the casualty.

​Bulk carrier Sirocco after the casualty.​​​

Breakaway of Bulk Carrier Sirocco and Subsequent Collision with Moored Barge

What Happened

​​On March 27, 2023, about 0208 local time, the bulk carrier Sirocco broke free from its moorings at the Convent Marine Terminal, located at mile 160.9 on the Lower Mississippi River in Convent, Louisiana, drifted downriver, and at 0249 collided with a barge moored at the Mosaic Uncle Sam dock at mile 160.4. There were no injuries, and no pollution was reported. The Sirocco, the barge, and the Mosaic Uncle Sam dock sustained damage totaling about $5 million. 

What We Found

​We determined that the probable cause of the breakaway of the bulk carrier Sirocco from the Convent Marine Terminal dock and the subsequent collision with moored barge MEM 5087 was the bow coming off the dock during cargo loading in the forward holds, exposing more of the vessel’s underwater hull to the strong river current, resulting in the brake-holding capacities of the ship’s mooring winches being exceeded and the lines paying out until the vessel broke free from the dock.​

Lessons Learned

​Preventing Vessel Breakaways While Loading in Strong Currents

To reduce the risk of a vessel breakaway, it is important for vessel crews to understand the forces that act on a vessel when it is moored into a strong current at a dock. Crews should ensure that slack is taken out of lines as the vessel loads, especially as the forward draft increases and the bow begins to sit lower in the water, exposing more of the hull to the current. Continuously monitoring and taking up any slack from bow lines as forward holds are loaded can help to ensure that the bow does not come away from the dock. Developing a response plan for a breakaway can ensure that crews are prepared to respond when one occurs. Vessel masters should also consider incorporating additional safety measures such as keeping propulsion, thrusters, and steering systems on short standby and having anchors ready for immediate use (even if not required by the loading facility). Vessel masters should be familiar with how to request tug support on short notice.


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