Comparative study of assessment the tanker ship behaviour in damage stability situations

Although the design of the actual tanker ships is in a continuous process of improving, in order that these ships to be safer constructed and operated, the casualties continue to occur. Such casualties, like collision or grounding, are generating damage to ship's hull that apart from the fact that can considerably reduce the ship strengths it can lead to dangerous situations in respect of ships stability. Damage stability assessment, especially for tanker ships, is a topic of high importance and continuous improvement. This aspect is evidenced by the activity of International Maritime Organizations and Classification Societies, which improve continuously the regulations in this respect. The objective of the present paper is to illustrate a study that reveals the assessment of a particular tanker ship behaviour in damage stability situations. The study was carried out for particular situations of damage to ship's hull, resulting in flooding of a number of compartments, combined with particular loading conditions of the tanker vessel. It is presented an analysis, based of calculations, between vessel's stability prior and upon occurring the flooding. The stability criteria, intact and damaged, defined by international conventions was assessed for each particular situation of damage. Moreover, the study point out if the ship's damage stability condition, for particular situations presented, is in line with the international requirements in force and if any improvements for damage stability are necessary. This study recommends that tanker ships to have a safe range of intact stability to prevent the occurrence of unstable equilibrium in case if stability is affected by flooding. It can be a benefit for the officers working on board tanker ships being used as a possible guidance for the situations of damage stability as it demonstrate that intact stability margins in different loading conditions can be close to lower limits in case of damage stability.