The U.S. Coast Guard is urging vessel owners and managers to routinely check anchor equipment for signs of wear and corrosion and make sure vessel crews are trained to spot problems.
When changing a ship’s anchor, it is important to use a replacement model that fits snugly and meets the vessel’s technical specifications, the agency said.
The Coast Guard issued a safety alert in May following an incident where the anchor chain on a freighter slipped up to 15 chain links during transit. The situation went unnoticed until the vessel’s hull was punctured from the repeated smashing of the anchor as the ship sailed through 15-foot seas. Crews learned of the problem when the ship’s forepeak flood alarms sounded.
“As a result, seawater flooded the bow thruster and emergency fire pump compartment,” the alert said. “The casualty resulted in excess of $1 million in vessel damage and a month’s lost revenues while the vessel was out of service.”
During repairs, officials learned components in the anchor system were severely worn. The windlass brake pads were reduced to less than 3 mm, severely hampering its ability to grab onto the massive anchor and chain.
“It was also discovered that the involved anchor had dissimilar specifications to the original anchor it had replaced,” the Coast Guard wrote. “As a result, the replacement anchor’s relative position in the hawsepipe was not the same because of its different shank length and connecting linkages.”
“The size difference prevented the riding pawl from properly engaging the anchor chain,” the alert continued.
Investigators learned that a wire sling had been threaded through an anchor chain as an additional slip-prevention measure. The wire sling was attached to the vessel and fitted with a pelican hook for ease of use by the crew, according to the alert. Positioning in this manner produced a sharp bend in the sling, exposing the interior wire strands to corrosion.
“The wire sling was inspected regularly, however, those performing the inspections were not instructed on how to examine and determine its serviceability,” Coast Guard investigators determined.
John Hess, a project manager with Safety Management Systems Inc. in Portland, Maine, likened the loose swinging anchor to a wrecking ball constantly pounding the side of the ship. Hess said situations like this are relatively uncommon. They are entirely preventable.
Based on the Coast Guard’s findings, there were multiple failures on the affected ship, which the Coast Guard did not name. Hess said the vessel’s original anchor was replaced with another model that didn’t fit exactly right. He said the vessel’s owner or operator should procure and install components that meet precise specifications, while inspection of this equipment falls to the vessel’s classification society.
Hess highlighted the importance of preventive maintenance and proper training for ship personnel. Even if components are inspected regularly, he said the crew needs to be able to recognize problems.
It’s critical that the ship’s owner/operator provide sufficient resources to ensure safe operation. Hess said it’s usually up to the chief engineer or chief mate to request new brake pads for the windlass.
The safety alert did not disclose whether or not spare brake pads for the windlass were carried on board, Hess noted. Brake pads of this type are typically replaced when they are worn to 9 or 10 mm thickness, a process that can be performed by the ship’s crew. In this case, he described the amount of wear as “dangerously excessive.”
“My point is age-old in the maritime industry: The crew cannot fulfill the requirements of the ship’s safety management system, which includes preventive maintenance, if the ship is not provided the financial resources required to make it happen,” he said.
The safety alert also did not disclose whether or not a locking bar at the riding chock was installed.
“A locking bar lays over an anchor chain link and is designed to keep the anchor chain from moving. It is like barring a door,” Hess said. “The locking bar is used when the anchor is deployed to take the strain off the anchor brake. But it can be engaged when the anchor is home to keep the chain from slipping if it lines up with the anchor chain links correctly, a condition that may not exist if the anchor is of an incorrect length.”
He said it is standard practice to attach a chain stopper just above the hawsepipe to keep the anchor chain from slipping when the ship is at sea.
“The parted wire sling may have been part of such assembly, but similar arrangements, often employing turnbuckles and appropriately sized shackles, prove more durable,” said Hess.
The Coast Guard issued a series of recommendations, some of which mirror Hess’ suggestions. The agency urged vessel owners and operators to update and follow preventive maintenance programs for anchor equipment, including the windlass.
When possible, specific instructions should explain when repairs are needed for the brake assemblies, the alert said. The Coast Guard suggested that vessel owners and operators make sure replacement components such as anchors are proper fits for the vessel. Maintenance personnel on board also should be training to recognize when components are due for upgrades or repairs.
“Lastly, the Coast Guard strongly reminds all maritime operators of the importance of performing regular maintenance and inspections on anchor-handling components to keep them ready for immediate release,” the alert said.
Coast Guard Sector Los Angeles developed the safety alert, which referred questions to Lt. Patrick Brown. Attempts to reach Brown were not successful because he has enrolled in a college program and is no longer with the sector, according to a Los Angeles-based spokeswoman. She was not aware of the anchor incident that led to the safety alert or the freighter involved.
Although anchor-related mishaps are rare, the incident shows they can be costly and dangerous.
“They were able to catch this early,” Hess said. “It could have been a lot worse.”