Cargo ships account for the majority of the around 53,000 merchant ships trading internationally, and it is those ships in which containers are stacked for transport. However, not all those boxes make their destination, with an average of 1,390 containers lost at sea each year.
Hardly comforting news for the offshore sailor.
When the 1200-foot G. Washington lost 137 containers, the Marine Accident Investigation Branch (MAIB), a UK government organization authorized to investigate all maritime accidents in UK waters and accidents involving UK registered ships worldwide, sought to determine why this happened. Here’s their report:
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 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.
For the full report, click here.
Published on February 10th, 2020