At 0127 on 20 January 2018, the UK flagged container ship CMA CGM G. Washington unexpectedly rolled 20° to starboard, paused for several seconds then rolled 20° to port. The ship was experiencing heavy seas in the North Pacific Ocean while on passage from Xiamen, China to Los Angeles, USA. As the sun rose later that morning, it was discovered that container bays 18, 54 and 58 had collapsed; 137 containers were lost overboard and a further 85 were damaged.
The MAIB investigation concluded that the collapse of all three bays probably occurred during the 20° rolls. The amplitude of the rolls exceeded the container ship’s estimated roll limits and was almost certainly the consequence of parametric rolling, which had been recorded by the ship’s motion monitoring decision support tool. The risk of parametric rolling was not identified by the master or his bridge team because they were unaware of the full capabilities of the decision support tool, and therefore were unaware of its predictions.
The investigation identified several factors that would have adversely affected the safety of the container stows on deck. These included: reduced structural strength of non-standard 53ft containers, inaccurate container weight declarations, mis-stowed containers and loose lashings.
The report concluded that:
– Bay 54 collapsed because the acceleration forces generated during the large rolls exceeded the structural strength of the non-standard 53ft containers stowed in the bay.
– Bay 58 collapsed because some of its containers were struck by the 53ft containers as they toppled overboard.
– Bay 18 collapsed as a result of a combination of factors and was probably initiated by the structural failure of one or more containers.
Action has been taken by CMA Ships, in conjunction with ABB, the manufacturer of the Octopus decision support tool, to improve its presentation of ship-handling advice to masters in bad weather. The training package for operators of this system has also been reviewed. Bureau Veritas, CMA CGM G. Washington’s classification society, has now amended its rules for the carriage of 53ft containers.
Recommendations have been made to:
– CMA ships, to ensure that, where container terminals routinely weigh containers prior to loading, the cargo plan is updated to reflect these weights.
– The Maritime and Coastguard Agency, to promote UK container owners’ involvement in Bureau Internationale des Containers databases.
– Bureau Veritas, to amend its rules to require the approved lashing software installed on the onboard loading and lashing computer to calculate and display maximum roll and pitch angles associated with ship loading condition and intended passage; and, review its rules and approval procedure to ensure Container Safety Certification data is accurately reflected within the contaainer ship’s loading and lashing computer, whatever the type of container, compliant with ISO standard or not.
Read the pdf report in full: 2020-2-CMACGMGWashington
Read the pdf annexes: 2020-2-CMACGMGWashington_Annexes