(WASHINGTON) — On Jan. 11 at 2:50 a.m. local time, the integrated tug and barge (ITB) Krystal Sea/Cordova Provider was transiting Prince William Sound in Alaska when the four lines connecting the tug to the barge parted, causing the barge to uncouple from the tug. The barge drifted, eventually grounding on the coast of Axel Lind Island, Alaska, at about 6:35 a.m.
There were no injuries and no pollution was reported. The barge Cordova Provider, valued at $2.9 million, was declared a constructive total loss by the vessel’s owner. The tug Krystal Sea was not damaged.
The National Transportation Safety Board (NTSB) determined that the probable cause of the grounding of Cordova Provider was due to shock loading that led to the parting of the push lines connecting the barge to Krystal Sea.
“When the lines parted, the seas were 4 to 6 feet with about 35-knot winds on the vessel’s port quarter, weather conditions that the vessel regularly encountered on its normal transit route,” the National Transportation Safety Board (NTSB) said in its analysis. “Since it was nighttime when the incident occurred, the mate and crewmember in the wheelhouse did not see what caused the lines to part or which line parted first. Five days before the casualty, the captain visually inspected the four push lines and noted no deficiencies. A post-casualty visual inspection of the recovered lines by a technician from a local industrial and maritime supply company found that the lines were in fair condition with no visible deficiencies and determined that all the push lines and the soft shackle parted due to the lines exceeding their breaking strength, likely due to shock loading.”
“Given that the ITB was in regularly encountered conditions and the lines were reported as properly rigged, it is undetermined how the first push line that parted was shock loaded. Once the first push line parted, this likely began a cascading failure as the remaining three push lines took up the additional strain,” the NTSB said.
Click here to read the complete report.
– National Transportation Safety Board
