NTSB: Shock Loading Caused Catastrophic Line Failure in Alaska ITB Grounding
An integrated tug and barge (ITB) operating in Alaska’s Prince William Sound suffered a complete connection failure when all four push lines parted during routine transit conditions, leading to a constructive total loss of the barge valued at $2.9 million, according to a National Transportation Safety Board investigation.
Investigators believe that after the first push line parted due to shock loading, the remaining three lines experienced a cascading failure as they took up additional strain. However, the NTSB noted it was “undetermined how the first push line that parted was shock loaded” given that the ITB was operating in familiar conditions with properly rigged lines.