How many ships hit bridges, lose power every year? Data shows jarring numbers on the rise.

An alarm wails onboard the container ship as it approaches the Francis Scott Key Bridge during what had until that moment seemed like a routine departure from the Port of Baltimore.

For the past half hour, the crew navigated the hulking vessel through relatively calm waters and lined it up to pass perfectly under the main truss of the steel bridge, softly lit in the early morning darkness.

Now, just a half mile from the span, the vessel has gone dark – no power, no steering, no propulsion. Inside the ship’s towering command center, the crew tries to re-engage the system but no luck. The nearly 100,000-ton ship is adrift.

“Captain, we are on a collision course with the bridge support,” announces the officer of the watch, who recommends dropping its anchor. No change. A desperate call goes out to the shore to stop traffic from crossing the bridge.

The captain realizes the hard truth: The Dali is “at the point of extremis,” he says – the point of no return.

The crew watches helplessly as the bridge looms larger and larger until, just four minutes after the alarm sounded, their vessel slams into one of its main support columns.

“At this point there is absolutely, certainly nothing that we could do on our own,” said Chief Mate Kevin Calnan from inside California State University Maritime Academy’s 360-degree mission simulator during an eerily vivid replication of the Baltimore bridge disaster.

The state-of-the-art simulator – one of just three of its kind nationwide – showed how a total loss of power on a container ship the size and weight of the Dali could turn it into an uncontrollable weapon of mass destruction – a transformation counted in precisely calculated currents and breezes, velocity and minutes, not hours.

Moments after the Dali struck it, the Francis Scott Key Bridge collapsed into Patapsco River, killing at least six construction workers, likely causing billions of dollars in damage and forever altering the Baltimore skyline.

Although such disasters are rare, the conditions that could cause them are frighteningly common, according to a USA TODAY analysis of U.S. Coast Guard maritime incident data, which includes any reportable maritime event involving a death or injury, collision, grounding, environmental harm, or the loss of power and propulsion.

Map: Where ships have struck bridges, lost power

This map shows issues categorized as "major" or "significant" marine casualties and “serious marine incidents” in U.S. Coast Guard incident investigation reports that mention a freight ship, freight barge, tank ship, tank barge or ocean cruise vessel striking a bridge. It also includes cases where ships lost power, propulsion or steering within two kilometers of a highway bridge over navigable waters. Don't see a map? Click here.

At least 6,000 times in the past 22 years – an average of more than five times a week – crews on board massive cargo ships, oil tankers, container barges and even cruise vessels have reported what befell the Dali: a loss of power, loss of propulsion, loss of steering, or some combination of the three, a USA TODAY data analysis reveals.

At least 900 of them occurred near bridges identified by the U.S. Department of Transportation as spanning navigable waters. The vast majority were classified as routine but a dozen were labeled major or significant.

Some damaged both the ships and the structures they hit. Others left crew members with broken bones or other injuries. But most, including cases remarkably similar to what happened last month in Baltimore, have never been made public, buried deep in a federal database.

Often the dividing line between major and routine came down to a last-minute effort by the crew or rescue teams.

The Verrazzano-Narrows Bridge had an earlier close call, in 2018

On March 16, 2018, the bulk carrier Strategic Alliance lost power and propulsion on the Delaware River just north of the Commodore Barry Bridge, a 2.6-mile span connecting Philadelphia to New Jersey and carrying more than 41,000 vehicles a day.

The Singapore-flagged vessel, about half the size of the Dali, dropped anchor in the channel without incident early that Friday morning and was able to regain propulsion and generator power after clearing its clogged cooling water strainers of debris. Nearly two years later, the Dali-sized container ship Maersk Chicago lost power in New York’s Lower Bay Channel as it approached the Verrazzano-Narrows Bridge late on a Wednesday night.

Roughly 500 feet from the country’s longest suspension span – crossed by nearly a quarter-million vehicles a day – the ship was adrift with no steering, no propulsion and no engine. Fortunately, a pair of tugboats were able to rescue the U.S.-flagged vessel and tow it to safety, where it was determined a broken air compressor valve was to blame.

Just last week, another container ship lost propulsion near the same bridge. The Liberia-flagged vessel, Qingdao, experienced the failure around 8:30 p.m. on Saturday as it navigated through the Kill Van Kull shipping lane between Staten Island and Bayonne, New Jersey.

It took three tugboats to bring the vessel under control.

Unlike most incidents in the Coast Guard database, the Qingdao made the news as images of the gigantic ship floating near the bridge spooked jittery Americans still reeling from the recent Baltimore disaster.

That the two events happened in close succession was not so much a coincidence, but rather a fairly common occurrence that’s bound to happen when tens of thousands of ships from all over the world travel in and out of U.S. waters every year, several maritime experts told USA TODAY.

Statistically, the experts said, such failures are more likely to happen in ports and harbors, as well as in close proximity to bridges, because that’s when the ships are under the most stress.

“That’s when you’re giving all your engine orders,” said Calnan, the assistant professor of marine transportation who ran the simulation at Cal Maritime for USA TODAY. Calnan has operated large ships himself and has experienced what is sometimes known as a dark ship, though only while out at sea.

“It’s just like in the car; if you’re going 65 on the highway, there’s not a lot happening,” he said, “But when you’re doing a lot of stop and go and changing engine orders, it’s putting stress on the engine, and if something is mechanically wrong with the engine itself, there’s a higher chance it will happen when you’re using it more.”

Mechanical failure, human error and a host of other conditions can conspire to shut down a vessel’s engine, seize up its propulsion system or thwart its crew’s ability to steer.

Sometimes a simple miscalculation can cause a crew to lose command of a ship – or cause an otherwise seaworthy ship to hit a bridge.

USA TODAY’s data analysis revealed at least 2,600 bridge strikes occurring in U.S. waters since 2002, the earliest year for which such data is available. Three of these allisions were fatal, claiming 16 lives in all. The majority, however, were minor – a ship’s antenna or mast hitting a bridge, or a barge clipping a bridge’s protective fender.

But maritime problems – which international governing agencies call “casualty incidents” – have been steadily rising over the past decade, according to a report by Lloyd’s List Intelligence, a global maritime data and analytics company.

That’s especially true for those caused by machinery damage or failure.

The Lloyd’s report cites 700 such reported events in the third quarter of 2022 – the highest in 14 years – and attributed the increase to several factors. Among them: fewer ship inspections and internal audits, an unavailability of dry docks and technicians to perform maintenance and repairs, as well as supply chain delays in getting spare parts.

Lloyd’s was unable to provide updated data, but a representative told USA TODAY incidents have continued to rise.

The crew could do little to avert catastrophe

The frequency of such malfunctions and the risks to life and property are at the heart of Cal Maritime’s simulation exercises, which train students how to react to the worst disasters in a controlled environment.

In the case of the Dali simulation, the unfortunate lesson was that there was little they could do to avoid a catastrophe once the power was down except alert others to their plight.

“Making that emergency call and alerting all of the other traffic in the area that, ‘Hey, we’re this ship and we can’t maneuver anymore, we’re not under command’ – that call itself is what we see in this accident in Baltimore,” Calnan said. “That singular call… saved countless lives.”

While most power outages cause minimal harm, the one that darkened the Dali occurred at a most unfortunate place and time: about 0.6 nautical miles from the Francis Scott Key Bridge while the laden ship was moving at a speed of roughly 8 knots and the wind was blowing from the northeast, according to real-time data fed into the simulator.

When the blackout occurred, the ship’s rudder was turned 3 degrees to the starboard side and remained stuck there as the vessel drifted off course. Its towering stack of containers acted as a sail for the wind, which aimed it directly at the bridge’s support column.

Even if the engine had been working, Calnan said, it would have taken 0.8 nautical miles to bring that particular vessel under those particular conditions to a full stop – farther than the distance to the bridge it was about to hit. Simply put, time had run out.

“During any situation on board any type of vessel, we have a concept which we call the point of extremis, which essentially means there’s a point in every situation where no matter what you do, it's going to lead to some form of undesirable outcome,” he said. “Basically, it’s the point of no return.”

National Transportation Safety Board and U.S. Coast Guard investigators are still working to determine the cause of the blackout on the Dali. They have retrieved documents and interviewed the crew, as well as others who witnessed or were involved in the crash. But it could be months before they release their findings.

In the meantime, maritime experts have offered a number of possible causes based on their own experience with engine failure.

“There are 101 potential reasons for a blackout,” said Capt. Ashok Pandey, a master mariner and associate professor of international maritime business at the Massachusetts Maritime Academy.

They include inexperienced crew members accidentally switching off a valve that shuts down the fuel supply, water forming inside poorly maintained fuel tanks and knocking out the engine, and countless situations involving dirty fuel gumming up the ship’s filters, pumps and injectors.

Deep-sea vessels like the Dali burn what’s known as heavy fuel oil – sometimes called bunker fuel – a cheap, tar-like residue that the crew processes onboard the ship by heating, filtering and purifying it before feeding it into the combustion system.

Sometimes the heavy fuel itself is particularly bad and can clog the ship’s strainers. Other times the crew fails to properly maintain its onboard processing system and dirty fuel gets into the engine. Either way, it can lead to disaster.

“We have all been through bad fuel situations – you get bad fuel and it clogs the strainers, and every engineer has had to go down and clean the strainers,” said Keith Deirup, a licensed chief engineer with 20 years of experience in the U.S. merchant marine industry. “If you lose an engine, it's a total loss of propulsion, and it takes a while to get it back online.”

Accidents, dirty fuel and fish cause blackouts 

Coast Guard incident reports blame a host of culprits for the power outages reported by hundreds of ships over the years. They include unpredictable events like lightning strikes, fires on board or even fish clogging water inlets meant to help cool the engines.

Several incident reports attribute power losses to dirty – or degraded – fuel, as was the case in June 2017, when the Hong Kong-flagged Mallika Naree went dark on the Elizabeth River outside Norfolk, Virginia. The bulk carrier dragged a buoy nearly 400 yards before running aground. The investigation revealed about 16 gallons of water had leaked into the fuel oil supply tank.

Delayed maintenance also shows up as a common cause of power outages. “Poor maintenance” on a fuel oil valve led to a power outage that ran the 681-foot-long Alexander Dimitrov aground east of New Orleans in January 2002. The report states “the valves should have been checked as part of routine maintenance.”

“Lack of inspection, testing replacement/maintenance of the time delay relays” was to blame in February 2019, when the captain of the Portuguese container ship EMS Trader ordered an emergency lowering of the anchor. The ship had lost power, steering and propulsion not far from the Commodore Barry Bridge southwest of Philadelphia.

Many of the incident reports blame human error and inattention.

The 1,096-foot-long container ship Ever Lotus lost power while mooring at the Port of Los Angeles in November 2016. Even though the vessel’s crew was trained to slowly increase the pitch of the bow thruster so as to not overload the generators, “the pilot adjusted the pitch from 0% to 100% instantly,” according to the incident report.

Three years earlier, the 604-foot-long Manistee went dark as it was backing out of Ashtabula Harbor east of Cleveland. The engineer on watch forgot to throw a switch that would prevent the generators from overheating, leading to the outage.

Such incidents reinforce the need for extra precaution when ships navigate near critical infrastructure, said Pandey of Massachusetts Maritime, who advocated for mandatory tug escorts regardless of the ship, its cargo or the port. 

Protecting bridges:Baltimore's Key Bridge, opened in 1977, had few ship defenses. Are modern bridges better?

“Increasingly, the use of tugs is considered too old-fashioned, maybe too expensive, simply because we have the technology,” he said. “It’s something we don’t talk enough about.”

Other experts said nothing can prevent every disaster, and the Dali might be a case in point.

“Naval engineers will look at the root causes and ask what we can do to prevent it from happening again,” said a senior government official and former Coast Guard officer who spoke to USA TODAY on the condition of anonymity because he was not authorized to talk to the media.

"And maybe there isn’t anything we can do,” he said. ”Maybe fate just caught up with it.”

More than half of major bridge collapses are in the U.S. 

Despite the frequency of power failures and bridge strikes reported to the Coast Guard, the maritime shipping industry has had relatively few major accidents like the one that toppled the Francis Scott Key Bridge.

Until this March, the last incident identified by USA TODAY in which a ship knocked down a U.S. bridge was on Jan. 26, 2012, when the Delta Mariner cargo vessel carrying rocket components down the Tennessee River from Alabama to Florida slammed into the Eggner’s Ferry Bridge near Aurora, Kentucky.

The ship, going about 10 knots, tore away a 322-foot span of the bridge as it attempted to pass under a section with insufficient clearance.

Fortunately, traffic was light and vehicles stopped before reaching the missing portion of the bridge, according to an National Transportation Safety Board report of the crash. There were no deaths or injuries, but the bridge sustained major damage. It was repaired and reopened later that year but permanently closed in 2016 after a new bridge was built in its place.

Three years earlier, in March 2009, a tugboat pushing eight barges on the Mississippi River knocked out the Popps Ferry Bridge in Biloxi, Mississippi, when it crashed into one of its pilings and sent a section of the span tumbling into the water. Again, nobody died.

Other ship-on-bridge allisions killed people but did not topple the span. This includes the July 2015 death of a construction worker on the Eads Bridge in St. Louis when a tugboat pushing two loaded barges struck his scaffolding as it was passing under the span. And the August 2014 death of a tugboat master when his crane barge hit the Florida Avenue lift bridge in New Orleans and the crane’s mast fell onto the wheelhouse, crushing him.

The last U.S. ship-on-bridge allision to cause both fatalities and bring down the bridge, according to USA TODAY’s review of the data, happened more than two decades ago.

On May 26, 2002, the towboat Robert Y. Love was pushing two empty asphalt tank barges on the Arkansas River when it veered off course and struck a pier supporting the Interstate 40 highway bridge near Webbers Falls, Oklahoma.

The impact sent a 503-foot section of the bridge tumbling into the river. Unlike the Kentucky bridge collapse, highway traffic on the I-40 span had continued to “drive into the void,” according to the NTSB report.

Fourteen people died and five were injured in the accident, which the report said caused an estimated $30.1 million in damage to the bridge and $276,000 to the barges.

Worldwide, between 1960 and 2015 ships or barges caused 35 major bridge collapses that killed 342 people, according to a 2018 report from the World Association for Waterborne Transport Infrastructure.More than half occurred in the United States.

Yet the United States has some of the strictest maritime standards in the world, according to the experts. Its rules and regulations – which include a host of technical, personnel and environmental practices – go far beyond those set by the International Maritime Organization, which governs all global shipping.

They ensure that U.S ships are built and maintained to the highest standards and that its crews follow industry best practices. These rules also apply, to a certain extent, to foreign-flagged ships in U.S. waters, even though those ships might operate under what some experts described as subpar conditions.

“Many of the world’s shipping companies are based out of countries like Liberia, Marshall Islands and Panama” Deirup said. “They do that to save on costs and liability, so they get to run these ships really cheaply. They hire mariners from whatever country they can offer the cheapest wages and will run a really shoddy operation without much oversight.”

Many of the ships, he said, “are just ramshackle.”

The U.S. Coast Guard has jurisdiction in U.S. waters and can detain a ship for safety issues, Deirup said, “but they’re spread really thin.”

Detainments typically happen when a Coast Guard inspection finds significant issues with a ship, but it takes years to train the marine inspectors and there aren’t nearly enough of them in the field, said the former Coast Guard officer who was not authorized to speak to the media.

Not all ships are inspected, either, he said. The Coast Guard uses an algorithm based on the vessel’s history and previous ports of call and current port to determine which ships to check.

Exacerbating the situation are the extremely tight schedules ships’ crews face to unload outgoing cargo and pickup inbound cargo before racing to the next port. That’s especially true of container ships, experts said, whose slots at ports are scheduled weeks in advance and must make it on time or miss the window.

“For this ship, the Dali, in Baltimore, they were probably under that pressure,” Deirup said. “That’s why if they had problems with their generators – just theorizing – but they might have been under a lot of pressure to just make it work and get off that dock.”

That type of pressure is difficult to mimic in a simulator, which is perhaps why the crew on the bridge of Cal Maritime’s digital ship operated with calm efficiency each time they ran through the scenario. Blackout, steering out, ship dead in the water, bridge looming, crash. Again and again and again.

Only one run involving tug boats averted the disaster, and even then only when two tugs at full power were tethered to the ship all the way under the bridge. That lineup is not a current day reality except in rare situations, such as tankers transporting oil or other toxins in certain ports.

Solutions:Tugboats left before ship reached Baltimore bridge. They might have saved it.

“No matter what nationality the crew was or what their training was like, I think in the end, it’s an unlucky situation at an unlucky point,” said Conor Finnerty, a Cal Maritime senior who assumed the role of officer of the watch during the simulation.

One of the most critical positions on the ship, the officer of the watch ensures the vessel navigates safely regardless of obstacles or conditions. During the simulation, Finnerty gave orders to the crew to continue testing the equipment, then to drop the anchor and, finally, to sound the danger signal warning anyone on the water that collision was imminent.

“There’s really not much that could have been done about it,” Finnerty said of the unfolding disaster, “except just watch it.”

USA TODAY reporter Dinah Voyles Pulver contributed to this report.