NTSB Reports on Pipeline Damage and Oil Spill Incident
The U.S. National Trasport Safety Board (NTSB) has released its report into the anchor contact of the articulated tug and barge Clyde S VanEnkevort / Erie Trader with underwater cables and pipelines finding several contributing factors.
On April 1, 2018, the articulated tug and barge (ATB) Clyde S VanEnkevort/ Erie Trader was westbound with a crew of 14 in the Straits of Mackinac, Michigan, when the barge’s starboard anchor, which had unknowingly released and was dragging on the bottom, struck and damaged three underwater electrical transmission cables and two oil pipelines.
About 800 gallons of dielectric mineral oil leaked into the water from the cables; the oil pipelines sustained only superficial damage. Repair and replacement of the cables was estimated at more than $100 million. No injuries were reported.
The NTSB has determined that the probable cause of the anchor contact with underwater electricity transmission cables and oil pipelines was the failure of the anchor detail to secure the barge’s starboard anchor, and the improper adjustment of the anchor brake band after the engineering crew replaced the brake liner, the combination of which allowed the anchor and chain to pay out under way.
During the accident voyage, the anchors were first ordered cleared when the vessel passed Gros Cap Reef. Neither of the two ABs on board, who were responsible for clearing and securing the anchors, stated that they cleared the starboard anchor. Although the second mate said he ordered the anchors secured when departing De Tour Reef (the last order to secure them before the accident), the AB on watch at the time stated he did not actually secure the starboard anchor despite communicating to the wheelhouse that all anchors were secured. Due to conflicting statements and lack of definitive information, it could not be determined when the starboard anchor was last cleared.
The report is available here.