The National Transportation Safety Board (NTSB) has released an investigation report on the bulk carrier Sirocco which broke away from its moorings and drifted in March 2023.
The incident
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. The vessel 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.
Probable cause
The National Transportation Safety Board determined that the probable cause of the breakaway of the Sirocco was the bow coming off the dock during cargo loading in the forward holds. This exposed more of the vessel’s underwater hull to the strong river current, exceeding the brake-holding capacities of the ship’s mooring winches and causing the lines to pay out, leading to the vessel breaking free and colliding with barge MEM 5087.
Lessons learned
To reduce the risk of vessel breakaways, it is essential for crews to understand the forces acting on a vessel moored in strong currents. Crews should ensure that slack is consistently taken out of the lines as the vessel loads, especially as the forward draft increases and the bow sits lower, exposing more hull to the current. Continuously monitoring and adjusting bow lines during forward hold loading can prevent the bow from coming off the dock. Additionally, developing a breakaway response plan and incorporating safety measures—such as keeping propulsion, thrusters, and steering systems on short standby—can improve preparedness. Masters should also be familiar with how to request tug support on short notice.
Did you subscribe to our daily Newsletter?
It’s Free Click here to Subscribe!
Source: NTSB
