Those piecing together what caused the accident will undoubtedly look at speed. The ship’s last known speed was 13.5 knots at 7:28 a.m., 12 minutes before the grounding, according to Bloomberg data.
That would have surpassed the speed limit of about 7.6 knots (8.7 miles an hour) to 8.6 knots that is listed as the maximum speed vessels are “allowed to transit" through the canal, according to the Suez authority’s rules of navigation handbook posted on its website.
Captains interviewed for this story said it can pay to increase the speed in the face of a strong wind to maneuver the ship better.
“Speeding up to a certain point is effective," said Chris Gillard, who was captain of a 300-meter container ship that crossed the Suez monthly for nearly a decade until 2019. “More than that and it becomes counter effective because the bow will get sucked down deep into the water. Then, adding too much power does nothing but exacerbate the problem."
Bloomberg data also show that the 300-meter Maersk Denver traveling behind the Ever Given also posted a top speed of 10.6 knots at 7:28 a.m. A spokesperson for Maersk in Denmark declined to comment. Ship captains and local pilots said it’s not unusual to travel through the canal around that speed despite the lower limit.
The Cosco Galaxy, a container ship marginally smaller than the Ever Given, was immediately ahead and appears to have travelled at a similar speed, though with a tugboat. The one ahead of the Cosco, the Al Nasriyah, also had an escort. The escorts are not mandatory, according to the Suez authority’s rules of navigation, though the authority can require it for ships if they deem it necessary.
“The biggest vessels often travel with a tugboat in close proximity, an escort boat, to facilitate the transit," said Captain Theologos Gampierakis at commodity trading house Trafigura Group in Athens.
A cargo ship with containers stacked high like the Ever Given can be particularly hard to navigate since the ship’s hull and wall of containers can act as a huge sail, said Kinsey, the former captain, who made his last trip through Suez in 2006 .
“You might find yourself positioning the ship in one direction, and you’re actually moving in another direction," said Kinsey. “There’s a very fine line between having enough speed to maneuver and not having too much speed that the air and hydrodynamics become unstable. Any deviation can get real bad real quick because it’s so tight."
About 20 minutes after the incident, the first of two tugboats accompanying the vessels ahead of the Ever Given came back to push its port side in an effort to dislodge it, according to data compiled by Bloomberg. Later, eight tugboats were deployed to push both sides of the container vessel, but to no avail.
