CLASSNK has released its “Guidelines for Container Stowage and Securing Arrangements (Edition 3.0)” and its “Guidelines for Parametric Roll Countermeasures”. It said the guidelines aim to achieve safer and more efficient marine transportation of containers.

The class society said the releases were in response to rapid increases in the size of container ships and advances in lashing technology. They provide evaluation methods for loading and lashing containers, incorporate the latest trends.

According to ClassNK, the guidelines reflect the load analysis combined with data from AIS and oceanographic data conducted during the comprehensive revision of ClassNK ship structural rules (Part C of its Rules and Guidance for the Survey and Construction of Steel Ships), and enable optimal stowage operations that take into account not only the route but also seasonal effects.

ClassNK said the Guidelines for Parametric Roll Countermeasures support the consideration of measures against parametric roll, which has been referred to as a factor in the recent cargo collapses on large containerships.

In addition to evaluation based on Interim Guideline on the Second Generation Intact Stability Criteria (MSC.1/Circ.1627), the guidelines outline the requirements for granting notation of ships with equipment and operational parametric roll measures. They also cover a wide range of aspects, both in theory and in practice, including the mechanism of parametric roll, its features and precautions, an overview of parametric roll response calculation, and devices and methods for countermeasures such as a practical and reasonable way for creating a polar chart that illustrates the danger of parametric roll.