The 'Svendborg Maersk' was in the Bay of Biscay last week as hurricane-force winds battered the Atlantic coast of Europe. Amid waves of 30 feet and winds of 60 knots, the Svendborg began losing containers off northern France.
After the ship arrived in the Spanish port of Malaga, Maersk discovered that about 520 containers were unaccounted for. Stacks of others had collapsed.
It is the biggest recorded loss of containers overboard in a single incident, CNN reported.
The company said that the extreme weather had an unexpectedly forceful impact on the ship's movements.
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It said 85 per cent of the lost containers were empty and others included such dry goods as frozen meat. None contained dangerous goods. Maersk is now contacting customers to tell them that their shipments are at the bottom of the ocean, the report said.
The Svendborg, which was on its way from Rotterdam in the Netherlands to Colombo in Sri Lanka via the Suez Canal, warned French maritime authorities that vessels should look out for floating containers, but most sank quickly in the mountainous seas. Thirteen have now been recovered, according to French officials.
The group claimed the containers were a lasting danger to fishing vessels and the environment.
Most containers will not float for long, especially in heavy seas. But one that is refrigerated may be buoyed by its insulation, and the use of polystyrene as packaging for goods also aids flotation.
In 2011, the World Shipping Council estimated that including "catastrophic losses" such as the capsizing of a vessel, about 675 containers were lost at sea annually.