The loss overboard of containers stowed on deck, a casualty whose frequency depends on a few extreme events and engages three covers at once.
Containers lost overboard means boxes stowed on deck falling into the sea through parametric rolling, lashing failure, excessive list or fire. The phenomenon changed scale with ship size, a modern container ship stacking up to eleven tiers above deck, the height where accelerations are greatest and inspection hardest. Three causes recur in investigations: weight under-declaration by the shipper, which corrupts the stability calculation, speed maintained in a beam sea, and fatigue in lashing gear. For insurance, a single event calls on the cargo policy for the goods, the hull policy for damage to the ship and liability cover for the locating and recovery costs imposed by coastal authorities, quite apart from a general average declaration if the ship jettisoned deliberately. The problem the industry has tried to solve is under-declaration, to which mandatory verified gross mass before loading has been a partial answer since 2016.
The container ship ONE Apus lost 1,816 containers in the North Pacific on November 30, 2020, one of the heaviest events on record. The World Shipping Council counted 3,924 containers lost in 2020 against 221 in 2023: the annual average says almost nothing in a distribution where two or three casualties make the statistic.
conteneurs tombés à la mer, boîtes perdues