A report on large container ship safety, growing out of the loss of the container ship MOL Comfort
, which broke in half in the Indian Ocean June 17, has been released, setting visual safety inspection and weight verification recommendations for large vessels.
Both halves of the ship later sank as they were being towed to port, but no members of the crew were lost in the accident.
English excerpts of the report were made available on the website of Japan’s Ministry of Land, Infrastructure, Transport and Tourism
, which established a Committee on Large Container Ship Safety to develop measures to ensure the safety of large container vessels. Nippon Kaiji Kyokai (ClassNK), the Japanese classification society, established a special Casualty Investigation Team in order to study and determine the cause of the casualty and was a member of the committee.
The committee said it is “still in the process of extrapolating the accident scenario and developing upon safety measures,” but recommended a number of actions be carried out on ships with loading capacities similar to or greater than 8,000 TEU class as temporary safety measures.
- “Visual safety inspections on the bottom shell plates to the extent possible should be conducted on large container ships which do not require ballast water to maintain stability.” It said these were primarily ships over 45 meters in breadth, carrying 8,000 TEU or more, and that the inspections are needed to look for buckling deformations. Where the deformations are found, it said a shipowner should consult with a classification society regarding the proper measures to be taken.
- With regard to the proper management of cargo weight on the hull for large container ships in the 8,000 TEU class and over in particular, the report said “cargo loading planning for actual voyages could be frequently reached to the maximum permissible still water bending moment (hogging condition).” It said in accordance with the deliberations at the International Maritime Organization (IMO) related to the enforcement of container weight verification prior to loading, “verification of the actual weight of container cargoes provided by the shipper is recommended as a safety measure for large container ships.” While an IMO committee recommended rules earlier this year to require verification of container weights, the rules have been strongly criticized by some groups such as the European Shippers Council and Asian Shipper Council.
- Other general items for caution include rough sea avoidance maneuvers such as speed reduction.
Class NK said that its casualty investigation team will continue to carry out numerical simulations of hull strength and acting loads, as well as conduct full-scale stress measurements of actual ships in order to develop comprehensive measures to ensure the safety of large container vessels, including potential amendments to existing classification rules related to hull structures.
Class NK also said it will work closely with a large container ship safety project team newly established by the International Association of Classification Societies’ (IACS) "to ensure that findings from the casualty investigation are reflected in IACS regulatory work."
MOL noted that it conducted emergency safety inspections targeting all six of the sister vessels of MOL Comfort
and then arranged docking for work to reinforce their hull structures as additional safety measures. With this step, MOL said the ships "secured about twice the hull strength of the standard" set by Class NK, which complies with IACS standards.
MOL said it "continues to pay special attention to the operation of this type of six sister vessels to reduce the stress on hulls by adjusting ballast water volume."
MOL said it also conducted safety inspections on the outer bottom shell plates of its operated large containerships in addition to the MOL Comfort
sister ships and "confirmed there is no safety problem."