Container losses during voyage in rough weather

Published in: Tech Session #3 2021, INAvation, Institute of Naval Architects, India

Author: Karan Doshi, Sharad Dhavalikar

Date of Publication: 24th Apr 2021

Container shift, damage and losses in rough weather are becoming more frequent as exemplified by recent incidents. Loss of Containers also poses a threat to the environment (especially when they are loaded with dangerous goods), a hazard for navigation especially for small ships and fishing vessels and of course financial losses.

Container loss incidents from 2010-2020 were identified. Available investigation reports of such accidents were collected and a study was performed to identify key trends & statistics, contributing factors and recommendations to prevent such events. The study highlighted that such incidents are more frequent for the Ships with Post-Panamax and higher sizes and these take place more frequently during the winter seasons in the Northern and Southern Hemispheres. The study identified that for prevention of such accidents, the container stowage and securing onboard should be implemented in accordance with the approved cargo securing manual. The actual container stowing configuration within stacks should be assessed using an approved lashing calculation program to ensure that the forces on the containers and the securing components do not exceed permissible limits. The study also identified that it would be beneficial if safe stowage plan considering the above is developed by shore offices and provided to the ship. Education and training of the ship crew along with support from onshore offices during rough weather to anticipate and avoid scenarios such as synchronous and parametric roll may also contribute to prevention of such incidents.

Further, there may be a need to review the computation of ship motions (and consequently the forces on the containers within the stack) considering various factors such as impact of climate change on waves, flexibility of the container stacks, possibility of parametric/synchronous rolling etc. It was highlighted that in order to unify the requirements towards container securing system design multiple numerical and experimental studies are required. Such studies are required to be validated with on-board measured data. Overall, this humungous task will require collaborative efforts from research bodies, flag states, classification societies, ship owners / operators and container securing system components manufacturers.

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