Study and analysis of container ship roll motions in adverse weather conditions remains an important issue for research in maritime industry as this aspect continue to expose the ships to dangerous situations that leads to loss of ships and cargoes. Once high and dangerous roll motions are developed, especially by the ships with large flares fore and aft, as container ships, it generates accelerations in the lashing equipment that exceeds the threshold values, leading to collapse of container stows as well as loos of containers overboard. In this paper is presented the results of the analysis of a container ship roll motions in adverse weather conditions in a particular area of navigation from North Atlantic Ocean. The analysis is based on a real case scenario of a container ship casualty occurred in a very common navigation route, generated by high roll motions and resulted in the collapse of container stows and a massive loss of containers overboard. The aim of this paper is to identify the causes and analyse the factors that generated the dangerous situation and the casualty. The simulations carried out and presented in this paper were performed by using the OCTOPUS Office 6 (AMARCON) software that can reveal the response on the ship in modelled energy spectrum environmental conditions. The results will lead to a better understanding of the root causes that generated the exposure of the ship to such dangerous situation and can be used as recommendations in order to avoid similar situations in the future.
Ships are mainly built to sail and transport cargo at sea. Environmental conditions and state of the sea are communicated to vessels through periodic weather forecasts. Despite officers being aware of the sea state, their sea time experience is a decisive factor when the vessel encounters severe environmental conditions. Another important factor is the loading condition of the vessel, which triggers different behaviour in similar marine environmental conditions. This paper aims to analyse the behaviour of a port container vessel in severe environmental conditions and to estimate the potential conditions of parametric roll resonance. Octopus software simulation is employed to simulate vessel motions under certain conditions of the sea, with possibility to analyse the behaviour of ships and the impact of high waves on ships due to specific wave encounter situations. The study should be regarded as a supporting tool during the decision making process.