Just minutes before the cargo ship Dali was scheduled to pass under the Francis Scott Key Bridge in Baltimore, alarm signals began blaring on the ship. The lights turned off. The engine stopped. Even the rudder, which the crew uses to maneuver the ship, was frozen.
During frantic efforts to revive the ship, the pilot quickly realized that the aimless ship was heading towards disaster and called for help.
The cascading collapse of the ship’s vital operating systems sent the Dali drifting until it finally collided with the Key Bridge, sending the span into the river and killing six people. But as crews this week continued to ponder tips on how to disentangle the ship and get better the bodies of the dead, investigators also turned to the biggest query: What could have caused such a catastrophic failure at the worst possible moment?
Engineers, captains and shipping officials around the world are waiting for that answer at a time when the industry’s largest ships can carry 4 times more cargo than those of just a few a long time ago, passing through crowded urban ports under bridges that may carry tens of 1000’s of people. people per day,
Several key questions are already emerging, in accordance with engineers and shipping experts monitoring the investigation, most of which point to the electrical generators that power almost every system on the 300-meter-long ship, not only lighting, navigation and steering, but in addition the pumps that provide fuel, oil and water for a huge diesel engine.
The “total power outage” reported by the pilot is difficult to clarify in today’s shipping world, where large industrial vessels now operate equipped with an array of automation, computerized monitoring, and built-in redundancy and backup systems designed to avoid just such a disaster.
“The level of redundancies has increased significantly over the last 30 to 40 years,” said John Carlton, a City professor of marine engineering at the University of London. “The ship today is very different from the ship it was 30 years ago.”
But there are various possible aspects contributing to the failure that investigators might want to trace as they interview crew members, check fuel supplies and check the ship’s systems that went down that night.
Improper maintenance could have caused a delay in starting the emergency standby generator, or an electrical failure could have prevented it from remaining on. Contaminated fuel or an by accident closed valve could have contaminated or starved the predominant generators. Human error could have caused problems or did not overcome them. The ship’s own automation could have led to equipment failures. A fireplace could also break out and damage key equipment.
The answers will impact not only international shipping, but in addition who’s liable for the damage, which S&P Global Ratings estimates at greater than $2 billion.
Grace Ocean Private, the Singaporean company that owns Dali, said it was “fully cooperating with government agencies at the federal and state levels.” Grace Ocean is owned by Yoshimasa Abe, a Japanese national who owns a minimum of two shipping lines and greater than 50 ships, including several of the largest container ships in the world. Although Dali was insured, Mr. Abe’s company could potentially face large claims, depending on investigators’ findings.
Given the scope of the failure, it is feasible that there have been multiple problems. Timothy McCoy, a professor specializing in marine engineering at the University of Michigan, said that, like a plane crash, a widespread failure of a ship’s systems normally involves a sequence of events.
An in depth have a look at the potential aspects involves many of the most vital elements of a modern cargo ship’s operation, including the fuel that powers the 55,000-horsepower diesel engine, which in turn powers the ship’s propeller.
The fuel also powers huge generators that provide electricity to container ships. And a ship like Dali needs electricity to run its predominant engine – its fuel injectors, for instance, are electrically powered – and control its rudder. Without electricity, the ship may drift.
An outbreak of fuel contamination led to problems reported last August on 32 ships sailing from Texas to Singapore, – said maritime industry officialsand a few of them reported loss of power and propulsion at sea.
Last 12 months in Washington state, a large passenger ferry ran aground after losing power resulting from bacterial and fungal growth in the ship’s fuel tanks, contaminating the ship’s filtration systems.
According to S&P Maritime Portal, a shipping data service, Dali had 4 generators when it was built in 2015. They normally don’t all operate at the same time, but container ships leaving port will normally be equipped with an extra generator to offer reserve power when needed. “At least two people should be online at the same time,” said Mark Bulaclac, a maritime researcher who also worked as an engineer on container ships.
If all generators were to run on the same source of bad fuel, it could cause them to fail.
Henry Lipian, a forensic accident investigator who previously worked for the Coast Guard, said the sudden loss of the ship’s generators led him to think about fuel problems as a possible perpetrator.
He said investigators would want to take a look at the fuel on board, the way it was delivered, whether it had been previously checked and what filtration systems were on the ship. However, he said one other explanation may very well be a problem with the fuel valves.
“I would like to start tracking all these fuel lines,” he said.
In Baltimore, investigators were taking a sample of Dali’s fuel to envision for quality, viscosity and signs of possible contamination, said Jennifer Homendy, chairwoman of the National Transportation Safety Board.
Still other experts said there have been also reasons to doubt the fuel contamination scenario. New fuels are typically tested, and duplicate filtration systems might help remove problematic ingredients that weren’t flagged during testing. There have been no reports of other ships experiencing problems with the same batch of fuel.
Marine engineers say the electrical chain response could even have knocked out all generators. If one generator fails, there could also be a situation in which there is just too much demand and too little electricity supply. Other generators are then in danger of damage, so the system will shut them down as well, said Richard Burke, a professor of naval architecture and marine engineering at SUNY Maritime College in New York.
“It was like we were both holding a big weight and I let go,” he said. “You can’t support it on your own, so you drop the burden.”
The power generator could also damage the ship’s electrical distribution system, said Capt. Morgan McManus, an instructor at SUNY Maritime College.
In the event of a failure of all predominant generators, ships depend on a standby generator, which is generally positioned above the waterline elsewhere in the ship and has its own fuel source.
Marine engineers say backup generators provide electricity to power some lights, the navigation system and, most significantly, the ship’s control system. Without a minimum of emergency power, you may’t move the rudder.
Since some lights got here back on after the initial power outage in Dali, it seems that the backup generator did indeed kick in, but only after a delay of about a minute. Even then, the lights appeared to exit after which come back on, increasing the possibility of a problem with the backup generator.
Ms. Homendy of the NTSB said this week that investigators had collected data “indicating a power outage” but were still trying to find out its extent.
Clay Diamond, head of the American Pilots Association, an industry group that’s in close contact with the Maryland port pilots, said control was restored after the emergency generator was activated. But even with a hard left turn and anchoring, there was not enough time to show or stop the ship.
Mr. Bulaclac, a shipping engineer, said backup generators must be tested recurrently by turning them on once a month for 2 hours. “I would like to know when the last time this emergency diesel generator was tested,” he said.
The Coast Guard inspected the Dali after docking in New York Harbor in September but found no deficiencies on the vessel. The Coast Guard didn’t provide details of what it conducted.
Ship modernization could have caused ships to fail in other ways. They increasingly depend on computers to watch problems and take motion after they are identified. In a sense, it’s a built-in layer of automatic protection: if one of the components becomes overloaded, it will possibly routinely shut all the way down to prevent further damage. But these downtimes could cause problems in themselves.
“I couldn’t rule out that some computer failure would close all the valves or pumps supplying fuel,” Lipian said.
Michael Forsythe AND Jenny Gross reporting contributed.
