In yet another instance of the cost of catastrophic failure likely outweighing the cost of maintenance, a rope has racked up millions in damages after failing.
In July 2022, cargo ship Thorco Basilisk was offloading part of a wind turbine at Greensport Terminal on the Houston Ship Channel in Houston. In the process, a hoisting rope broke on the ship-mounted crane. When it did, it caused the component to fall onto the ship’s cargo tween deck, causing between $3 million and $5 million in damages to the ship and the wind turbine part.
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At the time, the National Transportation Safety Board pinned the blame on the wire rope. Now, after an examination of the hoisting wire rope, the agency said it was definitely the rope’s fault. The agency said the rope showed significant external corrosion and wear that were obscured by the grease on the rope. The ship’s crew had been performing annual surveys on the wire ropes, but they couldn’t see any problems through all that grease.
The NTSB said the rope was still within its 10-year window for normal usage, but obviously it should have been discarded. The company has since changed its maintenance program and now requires wire ropes to be replaced every five years.
The report said “Saltwater and humid ocean air cause corrosion of metals, presenting challenges for the maintenance of high-strength steel wire ropes on vessels. A deteriorated wire rope directly affects a crane’s ability to safely and reliably handle loads up to its rated capacity. Therefore, diligent inspection, maintenance, and management of wire ropes are essential. Working wires should be changed at recommended intervals, or more frequently, depending on operating conditions and use.”
So, check your ropes, everybody.
