Tokyo-based classification society ClassNK has released draft amendments to its rules and guidance for container carriers, approved by the ClassNK Technical Committee on November 19.
The rules are scheduled to apply to container ships contracted for construction on or after 1 April 2016, three months before the application of the International Association of Classification Societies (IACS) new Longitudinal Strength Standard for Container Ships (Unified Requirement S11A) and Functional Requirements on Load Cases for Strength Assessment of Container Ships by Finite Element Analysis (Unified Requirement S34).
The amendments will come into effect after receiving approval from ClassNK’s Board of Directors.
The draft amendments are a result of the ClassNK’s response to Mitsui O.S.K. Lines’ MOL Comfort containership fire and subsequent sinking in June 2013, when it established the Investigative Panel on Large Container Ship Safety to investigate the possibility of casualty occurrence and the structural safety of large container carriers. The results from the investigation and ClassNK’s action plan were released in the Investigation Report on Structural Safety of Large Container Ships in September 2014.
The investigation concluded that it was actually possible that the load of the vertical bending moment exceeded the hull girder ultimate strength at the time of the accident when the effects of the deviations of the uncertainty factors like sea state of the time, yield stress etc were taken into account. Although, the report indicates that the overlap between the strength and the load was very narrow.
Japan’s Ministry of Land, Infrastructure, Transport and Tourism (MLIT) Committee on Large Container Ship Safety recommendations of requirements for large container ships, released in its Final Report in March 2015, also affected the amendments to relevant rules and guidance.