Expert Pawel Ziegler on the shipwreck in Baltimore: In this case the ship cannot maneuver

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Early Tuesday morning, the cargo ship Dali collided with the Francis Scott Key Bridge in the port of the American city in Baltimore. The ship drove towards one of the bridge’s two main support pillars, leading to its collapse. The crew had previously made a “Mayday” call and the power turned out to be causing problems, so the crew reported the loss of propulsion. As Pawel Ziegler, professor of nautical engineering and ship navigation at the University of Flensburg, says in an interview with Blick, such incidents can occur.

“Machine breakdowns occur in shipping for technical reasons,” says the expert. What can cause problems, however, is that if the ship is in narrow waters with potentially dangerous objects, things can become critical. In such a situation, the following applies: “In the event of an engine failure, the ship cannot maneuver.”

That could also have happened with the Dali

According to the crew, after leaving port they lost propulsion – at that time the Dali was traveling at a speed of only 8 knots, the equivalent of about 14.5 km/h. According to Ziegler, there is not enough current through the propeller to steer the ship with the rudder – so it remains on the last course without being able to maneuver. “The navigation systems are powered by an emergency battery in the event of a power failure on board,” he explains. “The rudder may even be temporarily disturbed.” It is possible that propulsion was lost first, making maneuvering impossible and that the power failure also rendered the rudders useless.

But there are two other options to help in such a case. The most important factor is enough time. This means that any existing bow and stern thrusters can minimally change the course – or an emergency anchor maneuver can be initiated: “But this emergency anchor maneuver also needs time and therefore also travel distance before it can have an effect (braking).”

The expert suspects that the short time and distance between the engine failure and the collision made it impossible for the crew to take emergency measures.

No autopilot in the game

According to Ziegler, these types of large ships in the area (ports, approaches, narrow waters, rivers, etc.) are manually steered with the support of a local pilot who is familiar with the waters. “This means that a helmsman on the bridge at the helm constantly receives heading or rudder angle commands from the captain or ship’s officer on watch,” says the expert. “The existing neighborhood pilot advises, advises and supports.” In the Baltimore case, a pilot was said to have been at the helm at the time of the accident.

According to Ziegler, the use of an autopilot at this point in Baltimore is unlikely: “Autopilot is only used for longer, clear and non-complex passages.”

The ship is probably further equipped with the standard safety mechanisms: navigation aids such as radar and electronic nautical charts (ECDIS). “The latter warns of shoals and the approach of collision objects if this function is correctly programmed and activated,” says Ziegler. What exactly happened on board and why the ship rammed the bridge remains unclear for the time being.

Source: Blick