Could tugboats have prevented the Baltimore bridge collapse? They would have helped, experts say

As the focus in the Baltimore bridge collapse shiftsfrom a rescue operation to aninvestigation of why it happened, some maritimeexperts have questioned why the ship didn't have tugboat guides with it right before impact and if they could have made a difference.

Early Tuesday morning, two tugboats owned by McAllister Towinghelped the container ship Dali out of the dock, according to marine shipping data analyzed bythe Baltimore Banner.They then left the cargo ship around 1:09a.m., the newspaper reported. At 1:25 a.m., the ship began veering right.

Theshipslammed into the pillar of the Francis Scott Key Bridge after losing power around 1:30 a.m. Tuesday. Thiscaused a long span of the bridge, a major link in the region's transport networks, to crumple into the Patapsco River.

WATCH | The moment the bridge collapsed:

Watch the moment when a ship hits a bridge in Baltimore, triggering collapse

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A container ship hit a major bridge in Baltimore, causing several vehicles to fall into the Patapsco River. Fire officials initially said crews were searching for at least seven people in the waters.

"The obvious answer is yes, they could have helped," Trevor Heaver, professor emeritus of transport operations and logistics at the University of British Columbia, told CBCNews.

"With tugboats attached, you have immediate power available to modify the movement of a vessel."

In Vancouver, any loaded tankermoving under the Ironworkers Memorial Bridge is assisted by tugboats, according tothe Vancouver Fraser Port Authority.

That said,it'snot really possible to say if tugboats could have stopped theaccident in Baltimore if they'dstill been attached to the vessel, Heaver added,because there werea number of factors at play, including the speed of the container ship, how far the ship was from the bridge when it lost power, and the size and power of the tugboats.

"They obviously would have helped. How much they would have helped, we have no idea."

At least eight people fell into the water as the bridge collapsed.Two were rescued, but the other six, part of a construction crew that had been filling potholes on the bridge, were missing and presumed dead. A search for their bodieswas underwayWednesday morning, according to Maryland State Police spokesperson Elena Russo.

Ina statement to CBC News, a spokesperson for McAllisterTowing said all its crew are "well andaccounted for," and its foremost concern is for the victims.

The role of tugboats

Tugboats areused to tow and pushlarger vessels, and one of their primary tasks is to "assist with the berthing and unberthing of ships, particularly in ports with challenging navigational conditions," according to the Marine Safety Consultantswebsite.

The Dali probably left the tugboatsafter departurein order to gain speed, Capt. Alain Arsenault, the executive director with the National Centre of Expertise on Maritime Pilotage, told CBC News Network.

He saidin some parts of the world, ships have what are called "tethering tugs" that go in front of the ship "and can help if something happens."

"But we don't have thatmany of that in the U.S."

LISTEN | How tugboats play arole in Halfax harbour:

Information Morning - NS8:24Halifax harbour master talks bridge safety in the wake of Baltimore tragedy

A full container ship lost power in Baltimore's harbour, just moments before it crashed into and collapsed the Francis Scott Key Bridge. We ask harbour master Captain Adam Parsons how might an incident with a drifting vessel play out in Halifax.

The port inHalifaxhas a number of safetymechanisms in place to avoid a similar tragicsituation,harbour master Capt.Adam Parsons told Metro Morning.That includes a requirement that any vessel over a specific length has one or two tugs tethered to it, Parsons said.

"So that if you have a situation or one of these incidents, the tugvesselscan bring the ship to safety."

Even with a fully loaded and massivecontainer ship, like the Dali, tugboats could "absolutely" stop it from drifting.

"The theory is, and the concept is, thatthe tugs can assistand stop the vessel depending on its location."

WATCH | How protected are Canadianbridges?:

How protected are Canadian bridges from collisions?

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The collapse of the Francis Scott Key Bridge in Baltimore has some experts questioning whether Canadian infrastructure could withstand such a devastating container ship crash.

'There are few things scarier'

Federal and state officials have said the crash appeared to be an accident.Capt. Michael Burns Jr. of the Maritime Center for Responsible Energy said bringing a ship into or out of ports in restricted waters with limited room to manoeuvre is "one of the most technically challenging and demanding things that we do."

There are "few things that are scarier than a loss of power in restricted waters," he said. And when a ship loses propulsion and steering, "then it's really at the mercy of the wind and the current."

When a ship loses propulsion power, it loses its ability to manoeuvre itself, Jin Wang, a professor of marine technology at Liverpool John Moores University, said on the Science Media Centre website.

"To avoid the shipping drift randomly to lead to possible collisions with other objects, the best way of mitigating possible consequences is to anchor the ship and also to ask emergency response and rescue services (e.g., tugs or similar ships) to assist the ship," Wang wrote.

Tom Sharpe, a former Royal Navyofficer, wrote in the Telegraph thatgiven the speed of the Dali, a tug forward would have struggled to have any"lateraleffect" on the collisioncourse. But a tugboat attheaft, or rear of the ship, may have made a difference.

"There is no reason (other than time and money) why [the ship] couldn't have had a tug attached aft or at least had one close by. This would have given the ship so many more options."