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Shipping industry experts were taken aback following a federal report describing last year's anchor strike on the controversial Line 5 oil pipeline in the Straits of Mackinac. 

A 12,000-pound anchor accidentally dropped into the Straits, sliced five cables, dinged the dual oil pipeline and lost its flukes and crown, and wasn't discovered until the tug and barge to which it belonged neared Indiana Harbor. At the other end of Lake Michigan. Two days later. 

“That’s a bunch of bull----,” said a flabbergasted Frank Frisk, a Great Lakes maritime consultant who worked on Great Lakes freighters. “The shipping company’s at fault for that one, for not having the boat properly manned.”

The April 1, 2018 anchor strike hastened negotiations between the state of Michigan and Line 5 owner Enbridge about the future of the 66-year-old pipeline on the Straits lake bed. And the June National Transportation Safety Board report on the incident was featured in Attorney General Dana Nessel’s lawsuit seeking a permanent injunction from the courts on the operation of Line 5’s Straits segment.

A report issued a year prior to the April 2018 incident cited anchor strikes as the biggest risk to Line 5 pipeline, but records of such strikes in the area are hard to find.

Prior to the 2018 incident, state agencies have records for one to three anchor strikes in the Straits that date back to the late 1970s. Federal agencies have no ready records to prove any other anchor strikes in the Straits or the Great Lakes other than the 2018 incident.

That's not to say anchor strikes don't happen — in the Great Lakes and elsewhere. A 2017 study by a Norwegian maritime and oil and gas risk analysis group estimated that globally there were seven to 10 anchor losses per 1,000 ships between 2007 and 2015 and cited concerns about an increase in anchor strikes.

All it takes is one of those lost anchors to snag or hook into the pipeline and reap disaster, as was nearly the case in 2018, said Capt. Dan Gallagher, president of the Lake Pilots Association.

“There’s always a risk, yes,” Gallagher said. “I think everybody in the maritime community has taken this very seriously.”

Few records on strikes

A state-commissioned 2017 study meant to analyze the potential risks associated with the Straits pipeline noted anchor strikes represent 75% of the annualized total failure probability. An engineer from the group that conducted the analysis said there was about a 1-in-60 chance of failure on the roughly 4-mile segment over 35 years. 

But in the Great Lakes, records indicating such inadvertent strikes, dragging or snagging are scarce.

The only state evidence of an anchor strike prior to the 2018 incident traces back to a letter sent by Consumers Power Company to the Michigan Department of Natural Resources in June 1979, correspondence referenced in Nessel’s lawsuit.

The letter notes that an April 1979 outage on the company’s 46-kilovolt cables crossing the Straits was believed to have occurred because “a ship dragging anchor accidentally hooked into the cables,” severing two and damaging two others. The Consumers Power’s easement required it to notify the DNR of the repairs, one of the only reasons the DNR had a record of the assumed anchor strike. 

Two other letters between the department and Consumers Power in 1983 and 1986 also mentioned damage to submerged Straits cables, but don't cite the cause of the damage.

The National Transportation Safety Board said the 2018 incident in the Straits is the only Great Lakes anchor strike it has investigated in the past decade.

The Detroit News submitted a Freedom of Information Act request to the U.S. Coast Guard for records of prior anchor strikes in the Great Lakes. The agency said such a search would require personnel to look through more than 6,000 marine casualty reports to determine which ones involved an anchor strike, a roughly 1,000-hour task.

Even if the Coast Guard reviewed each report, evidence of anchor strikes are probably scant, said Lorne Thomas, a former maritime investigator who is now chief of external affairs for the Coast Guard’s 9th District in Cleveland.

“I’ve been in the Cleveland office since 2002 — close to 17 years. I have not been made aware of an anchor strike prior to the one last year,” Thomas said.

The Norway-based DNV GL found the loss of an anchor was one of the top five incidents cited for shipping insurance claims in 2016 and occurred seven to 10 times per 1,000 ships each year between 2007 and 2015. The study, an earlier version of which was cited in the state's 2017 Line 5 risk analysis, noted that incidents of lost anchors, while more easily tracked, are not necessarily the same as dragged or snagged anchors.

The Line 5 twin spans are in a busy shipping lane and lie exposed on top of the lake bed in shallow water relative to the anchor chains of passing vessels, making them more vulnerable to such an incident, according to the Dynamic Risk Assessment Systems report.

“Furthermore, a 20-inch diameter pipeline is small enough to fit between the shank and flukes of a stockless anchor for a large cargo vessel, and thus, is physically capable of being hooked,” the study concluded.

Anchor, pipeline oversight

The risk would not necessarily be reduced by anchor warnings posted in and around the Straits since the study largely looked at inadvertent deployment, as happened in April 2018.

The National Transportation Safety Board concluded the Straits anchor strike resulted from human error and mechanical failure associated with a newly repaired anchor brake band.

Sometime before the Clyde S. VanEnkevort tug boat and the Erie Trader barge proceeded west through the Straits April 1, the vessel’s 12,000-pound anchor let out and dragged across the Straits bed.

The anchor is believed to have sliced through three American Transmission Company cables, spilling more than 800 gallons of dielectric mineral oil, hit two other Consumers Energy retired lines and dented Line 5. The damage to the ATC cables alone was estimated to be about $100 million.

Two days later, as the tug and barge neared Indiana Harbor near Chicago, a crew member noticed the anchor chain was rubbing against the barge’s hull and realized the anchor had been inadvertently released. When the anchor was pulled back on board, it was missing two flukes and the anchor crown, which have yet to be located.

The captain notified his company and proceeded to the ship's next port, reportedly feeling no need to notify the U.S. Coast Guard because the agency only requires one anchor.

Soon after the 2018 incident, state and federal agencies created no-anchor zones in the Straits. At the request of Michigan Gov. Gretchen Whitmer, the DNR is expected to meet with the Coast Guard this month to develop a system requiring U.S.-flag and foreign vessels to notify authorities that their anchor is up before crossing the Straits, said DNR spokesman Ed Golder. 

A web of federal and state agencies oversee and enforce different aspects of pipeline safety, a network that widens when it comes to submerged pipelines, said Nick Assendelft, a spokesman for the Michigan Public Service Commission.

While the commission or the federal Pipeline Hazardous Materials Safety Administration would oversee damage assessment, repairs and safety on a pipeline, the U.S. Environmental Protection Agency, Coast Guard, DNR or Department of Environment, Great Lakes and Energy may step in to lead a spill response.

“The lead agency, whether local, state or federal, depends on where the incident occurred, the type of pipeline involved, the severity of the incident and other factors,” Assendelft said. “All these agencies and responsibilities would be coordinated through an Incident Command System.”

The federal pipeline safety administration's website records 274 pipeline incidents from 1999 through 2018. While it notes Enbridge’s 2010 oil spill in Marshall — the largest inland spill in U.S. history — the 2018 anchor strike is not included because no oil was spilled.

The Coast Guard has yet to issue its final report on the 2018 incident, but generally the agency requires ships to make a marine casualty report for any collision or significant failure in the ship's function, Thomas said. There is no special requirement for reporting an anchor strike, he said, given the low occurrence of such an event.

“This doesn’t happen that often where you would have a need for a robust system to track individual vessels and get the whereabouts of their anchor at all times," he said.

From the captains quarters

Nonetheless, there are rules and designated areas where a ship can and can’t drop anchor, and any captain worth his or her salt knows where they are, said Gallagher of the Lake Pilots Association, a group of American and Canadian pilots who shepherd foreign vessels through designated U.S. and Canadian waterways.

“If there’s pipelines around, of course you would never drop the anchor,” Gallagher said.

There are exceptions. When ships proceed through confined waterways like the St. Mary’s River or when preparing to make dock, they “clear” the anchor to prepare it for emergency deployment, said Jim Weakley, president of the Lake Carriers Association. In such close quarters, the ability to drop an anchor may be the only way to stop a collision in the event of a steering or engine failure.

“It gives you the ability to change the pivot point to the anchor … to maneuver based on that anchor’s position and also, hopefully, gives you the ability to stop the ship,” he said.

But those emergencies requiring a dropped anchor in an undesignated area are few and far between, said Sam Buchanan, who delivers mail to freighters on the Detroit River aboard the J.W. Westcott.

“I’ve been on the river for 34 years,” Buchanan said. “I’ve only seen a handful of ships have to drop it on the river because of a problem, and it's only because they’ve lost their steerage or their engine.”

Interlake Steamship Company’s 1,000-foot vessels on the Great Lakes have cameras near the anchor to check them from the pilot house and avoid an inadvertent drop, said Paul Christensen, director of vessel operations for the company.

“It’s very rare to release the anchor unintentionally,” he said.  

A recent incident in the Detroit River is an example of such a similar emergency deployment, Christensen said. 

On June 15, when ropes tying a 730-foot freighter to shore snapped in Sandwich town, across from Zug Island in Detroit, the ship dropped its anchor to stop from drifting. The anchor landed about 100 feet downstream from a liquid ethane pipeline and propane pipeline buried about nine and 10 feet below the riverbed.

The pipelines were undamaged, but Whitmer said the second unplanned anchor release in a little over a year reinforced the need to get Line 5 out of the Great Lakes.  

The Detroit River scare, she said, “just confirms for me that we have to take this very seriously, and an oil pipeline going through the Straits of Mackinac is an incredibly risky thing to do.”

eleblanc@detroitnews.com

(517) 371-3661

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