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Accidents

Sirocco (2023)

On 27 March 2023, the Panama-flagged bulk carrier Sirocco broke free from its moorings at Convent Marine Terminal on the Lower Mississippi River while loading coal. The vessel drifted about half a mile downriver and at 0249 collided with the moored barge MEM 5087 at the Mosaic Uncle Sam dock. The NTSB reported no injuries or pollution and estimated total property damage at approximately USD 5 million.

Classification

  • Incident Type: Collision
  • Initiating event: Mooring breakaway
  • Severity: High, because the casualty caused a constructive total loss of MEM 5087 and approximately USD 5 million in property damage.
  • Tug involvement: Yes

Vessel Details

FieldValue
Vessel NameSirocco
Vessel TypeBulk carrier
Flag StatePanama [PA]
IMO Number9603996
Gross Tonnage43,974 GT ITC
LOA (m)229.5
Breadth (m)32.2
Year Built2014
Persons aboard31
OwnerMazovia Investments Inc.
OperatorV.Ships Asia Group Pte Ltd
ChartererOldendorff Carriers GmbH

Other involved craft

CraftRole
MEM 5087Moored barge struck by Sirocco
Glenn SMoored crane barge at the Mosaic Uncle Sam dock
Burnside IIMoored deck barge at the Mosaic Uncle Sam dock
Savannah, South Carolina, Elizabeth BTugs that responded or assisted after the breakaway

Incident Details

FieldValue
Date2023-03-27
Breakaway locationConvent Marine Terminal, Lower Mississippi River mile 160.9
Collision locationMosaic Uncle Sam dock, Lower Mississippi River mile 160.4, Convent, Louisiana
Coordinates30.0382, -90.8362
RegionUnited States
Persons aboard31 on Sirocco; 0 on MEM 5087
Fatalities
Injuries0
Missing
CargoApproximately 73,014 tons of coal loaded
Direct DamageApproximately USD 5 million in property damage
Economic Damage
Environmental damageNone reported

Key facts

  • The Sirocco broke away at approximately 0208 local time while loading coal at Convent Marine Terminal.
  • Its bow came off the dock during loading of the forward holds, exposing more underwater hull to a strong river current.
  • The vessel drifted approximately half a mile downriver before its starboard quarter struck MEM 5087 at 0249.
  • The NTSB identified the Sirocco, MEM 5087, and the Mosaic Uncle Sam dock as sustaining damage totaling approximately USD 5 million.
  • MEM 5087 suffered extensive hull and structural damage and was considered a constructive total loss; Glenn S and Burnside II and the dock also sustained damage.
  • The NTSB reported no injuries and no pollution. It did not provide a separate normalized economic-loss figure.

Narrative

The Sirocco arrived at Convent Marine Terminal on the Lower Mississippi River on 26 March 2023 and moored starboard side to the north dock with 16 lines. The vessel was scheduled to load approximately 73,014 tons of coal. Two hold-in tugs initially pushed the vessel into the dock under the terminal's high-water loading arrangement.

The Carrollton gage fell below the terminal's 12-foot threshold on 26 March. The aft tug was released at 1315 and the forward tug at 1500, although the master had expressed concern about the strength of the river current. The NTSB recorded current readings of approximately 3.2 to 4.5 knots and repeated observations of slack mooring lines.

At 0050 on 27 March, loading shifted to forward hold no. 2. At about 0145, the second officer and an able seaman found the bow approximately 1.5 metres off the dock and could not heave it back alongside. The master requested immediate tug assistance at 0201. At 0208 the bow moved farther away from the dock, and at about 0213 a mooring line parted while the remaining lines paid out.

The Sirocco's anchors and responding tugs slowed the drift but did not prevent the vessel from reaching the Mosaic Uncle Sam dock. At 0249 the starboard quarter struck the port side of MEM 5087. The Sirocco, MEM 5087, the nearby barges, and the dock were damaged. A third tug and a pilot later assisted the vessel to Grandview anchorage, where it was secured with both anchors holding.

Sequence of events

Date/timeEvent
2023-03-14The Carrollton gage exceeded 12 feet, activating the terminal's high-water loading plan.
2023-03-26 0100Sirocco moored at Convent Marine Terminal with 16 lines.
2023-03-26 0300Coal loading began.
2023-03-26 1315The aft hold-in tug was released.
2023-03-26 1500The forward hold-in tug was released.
2023-03-27 0050Loading shifted to forward hold no. 2.
2023-03-27 approximately 0145The bow was found approximately 1.5 metres off the dock.
2023-03-27 0201The master requested immediate tug assistance.
2023-03-27 0208The bow began moving farther away from the dock.
2023-03-27 approximately 0213A mooring line parted and the vessel broke free.
2023-03-27 0249Sirocco struck MEM 5087 at the Mosaic Uncle Sam dock.
2023-03-27 approximately 0305A pilot boarded and took the conn.
2023-03-27 approximately 0600Sirocco reached Grandview anchorage.

Contributing factors

FactorEvidence statusDescription
Bow came off the dock during forward loadingConfirmed findingThe NTSB's probable cause was that forward cargo loading increased the exposed underwater hull area and the resulting current force exceeded the mooring winch brake capacity.
Mooring winch brake capacityConfirmed findingPost-casualty inspection found extreme heat and friction on the forward brake liners, consistent with line tension exceeding brake capacity.
Simultaneous deck dutiesReportedThe NTSB analysis records that watchstanders tended mooring lines while also performing cargo, hatch, sounding, and security duties.
Release of hold-in tugsReportedThe terminal no longer required hold-in tugs after the Carrollton gage fell below 12 feet, even though the current remained strong.
Limited starboard-anchor deploymentReportedThe starboard anchor was released to one shot, which was insufficient to reach the river bottom at the reported depth and deck height.
A longer starboard-anchor deployment might have arrested the driftSuspectedThe NTSB treated this as a conditional possibility, not a certain outcome.

Investigation

The National Transportation Safety Board completed marine investigation DCA23FM024 and issued Marine Investigation Report MIR-24-25 on 29 August 2024. The NTSB's probable cause was the bow coming off the dock during forward-hold loading, exposing more underwater hull to the strong current, exceeding the mooring winches' brake-holding capacity, and allowing the lines to pay out until the vessel broke free. The investigation was conducted with cooperation from Coast Guard Sector New Orleans.

References

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