The Danish shipping giant has also ordered all seven other E-class ships not use their stern thrusters until investigators discover what caused the incident.

Reports say the engine room of the 15,500-teu Emma Maersk (built 2006) has been left under eighteen metres of water.

Maersk Line’s Head of Ship Management, Palle Laursen, said the investigation into the incident was still ongoing, and that repairs will take time.

“Initial inspections by divers show that the water ingress was caused by damage to one of the stern thrusters,” says Laursen.

“It is now known that several propeller blades have broken off and there is severe damage to the propeller mounting, resulting in a crack in the forward stern thruster tunnel which caused the ingress of water.”

While it is still unclear what caused the damage, Palle rules out any human error by the crew. “The crew handled the situation very well and did exactly what they should at all stages,” he said.

“The E-class has been sailing well since 2006, and the thrusters are used at every port call,” Palle adds, stressing that for now it is seen as an isolated incident.

“Until we know the exact reason, we have as a precautionary measure instructed the other vessels in the E-class fleet not to use their stern thrusters.”

Maersk Line was keen to point out that at no point was the ABS-classed Emma Maersk in danger of sinking.

“Naval architects have confirmed that a fully loaded E-class vessel can sustain full flooding of the engine room and still stay afloat,” it said.

“Large container vessels have a natural better stability than smaller vessels. Had the incident occurred at sea, it would have been a matter of getting an oceangoing tugboat in place to assist.”

Palle says making the Emma Maersk seaworthy again is a complicated process, and admits it is probably a matter of months before she can enter service again.

“The first priority is to preserve the equipment, which ironically means keeping it submerged for the time being,” he says.

“Due to its exposure to salt water, any contact with oxygen will result in corrosion. So the plan is to have underwater welders plug the hole before lifting the vessel further, after which the remaining cargo onboard will be unloaded, water will be pumped out, and the equipment will be washed with fresh water, dismantled and retrofitted.”

Palle says several uncertainties remain including whether a full dry-dock operation is needed for the 397 metre long ship.

Even if it can be done while the vessel is waterborne, Palle says there is the question of location: is Suez suitable for the operation, or will it be necessary to tow the vessel to another location.

“These and other questions will be determined during the coming days and weeks. Cargo operations and customer relations continue according to plan to minimise the disruption as much as possible.”