Heavy-Lift Hoist Failure Due to Corrosion: NTSB Report

The National Transportation Safety Board (NTSB) reported that undetected corrosion and wear led to the failure of a wire rope during the hoisting of a wind turbine component on the heavy lift ship Thorco Basilisk, resulting in $3-5 million in damages. The incident occurred on July 23, 2022, when a wire rope on a shipboard crane broke while offloading a 68-tonne wind turbine nacelle at the Greensport Terminal on the Houston Ship Channel. The failure caused the component to drop onto the vessel’s cargo hold tween deck, resulting in significant damage to the ship and the nacelle.

Investigations revealed that the 1.5-inch wire rope showed obvious signs of external corrosion and wear, with sections on either side of the location where the rope had parted exhibiting a significant level of external corrosion. The crew had followed the common maritime industry practice of leaving the old grease on their wire ropes during maintenance, as removing the old lubricant would be impractical without specialized equipment. Despite the wire rope being within the standard 10-year service lifetime, NTSB determined that it was near the end of its service life and should have been discarded. As a result, vessel operator Auerbach Marine updated its maintenance schedule to require crane wire rope replacement every five years, in line with NTSB recommendations.

The NTSB emphasized that saltwater and humid ocean air cause corrosion of metals, presenting challenges for the maintenance of high-strength steel wire ropes on vessels. The deteriorated wire rope directly affects a crane’s ability to handle loads safely and reliably, highlighting the importance of regular maintenance and replacement of wire ropes to prevent similar incidents in the future.

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