Classification society ClassNK has released the second edition of its Guidelines for Container Stowage and Securing Arrangements in response to the increasing size of containerships.

Last year, the average size of newbuilding was more than 7,000 TEU and new securing technologies have been developed to enhance loading containers on board these ever-growing vessels, said the ClassNK statement.

"Consequently, it has become important to evaluate the adequacy of such container stowage and securing arrangements. Taking into consideration ISO standards, the growing diversity of actual stowage and securing methods on container vessels and loads acting on containers due to ship motions, ClassNK has developed strength evaluation methods for safer stowage and securing arrangements," the statement said.

The news guidelines include amendments to evaluation methods to allow for the consideration of the effect of sea routes on stowage and securing.

"For those vessels installed with lashing calculation programmes capable of evaluating container lashing strength, a new class notation can be affixed," the statement said.

In addition, procedures related to affixing class notations for ships in compliance with the IMO regulations on providing safe working conditions for securing of containers on deck in CSS Code (Code of Safe Practice for Cargo Stowage and Securing) Annex 14 have also been included in the updated guidelines, it said.

"Although this is a non-mandatory code, a number of states have been requiring that containerships calling at their ports comply with the CSS Code, and the ClassNK guidelines now include an audit of ships to ascertain that they comply with the CSS Code Annex 14," said ClassNK.