ClassNK releases amendments to class rules including structural strength requirements of container carriers

By Curious

Leading classification society ClassNK has announced that it released amendments to its Rules and Guidance for the Survey and Construction of Steel Ships on 25 December 2015, including structural strength requirements of container carriers.

In response to a large container ship casualty in June 2013, ClassNK established The Investigative Panel on Large Container Ship Safety, which comprised of shipbuilders, shipping companies, and people with relevant knowledge and experience, 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.

ClassNK releases amendments to class rules including structural strength requirements of container carriers

On the other hand, Japan’s Ministry of Land, Infrastructure, Transport and Tourism (MLIT) Committee on Large Container Ship Safety released recommendations of requirements for large container ships in its Final Report in March 2015.

Furthermore, the International Association of Classification Societies (IACS) adopted the 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).

In line with its action plan for rule amendments and the recommendations by the MLIT Committee, ClassNK has updated its independent longitudinal strength requirements in consideration of the effects of whipping*, and the effects of sea water pressure and container loads. The amendments also reflect the new IACS Unified Requirements (UR) S11A and S34.These amendments will apply to container ships contracted for construction on or after 1 April 2016, three months before the application of the IACS UR S11A and S34.

Mr. Yasushi Nakamura, ClassNK Representative Director and Executive Vice President said:

“The development and application of the container ship rule amendments reflects our firm commitment to providing the industry with the appropriate technical standards. The new rules will contribute to even safer ship building and design and we will continue devoting our effort to further improving safety in the maritime industry.”

The amendments also include requirements related to the following:

  • Propeller shaft and stern tube shaft surveys;
  • Welding procedures and related specifications;
  • Scope of application of fire-resistant cables;
  • Fire safety measures for vehicle carriers transporting motor vehicles powered by compressed hydrogen or compressed natural gas;

( * whipping - Transient elastic vibration of the ship hull girder caused by wave impact loads on the hull such as slamming)