New initiative to tackle boxship roll
Illustration of a container ship equipped with ART (areas coloured in yellow indicate ART)
(Source: ClassNK)
ClassNK, Nihon Shipyard Co Ltd and IMC Co Ltd have signed an R&D agreement to expand anti-roll tank (ART) applications to large container ships. ARTs are designed to limit a ship’s rolling motion by the transfer of liquid, usually water, in the reverse direction of roll. Ships with large flared decks are susceptible to the phenomenon.
Effective limitation of roll motions improves seakeeping and operational safety, and can raise container loading efficiency. Most importantly, it can prevent parametric roll, a phenomenon that can cause ships to roll to very large angles, even in moderate sea conditions. This can lead to the collapse of container stacks, the loss of boxes overboard, or in extreme cases, severe risk to the ship itself.
In its ‘Guidelines on Preventive Measures against Parametric Rolling (Edition 1.0)’, ClassNK has set out the requirements that will enable it to grant a notation to ships equipped with ART. The move follows a programme of ART-related research and development carried out last year.
In the joint project, Nihon Shipyard will produce an optimal installation plan of ART for large container ships. IMC will demonstrate the efficacy of the system in operation on a vessel, and ClassNK will establish appropriate evaluation methods, and update guidelines and regulations with practical requirements.
