The Study On Second Criterion For Dead-ship Stability

In the past ten years, more and more sea accidents have happened. In order to ensure the safety of Marine life and property, International Maritime Organization (IMO) is now drafting the second generation intact stability criterion. Starting from the second generation intact stability criterion has been put forward and after several years of development, this criterion is divided into five parts:Parametric roll, pure loss of stability, dead-ship condition, surf-riding/ broaching and excessive accelerations. Five failure modes all have three tier criterion. computational accuracy is higher and higher from the first to the third tier.The first and second tier criterion have been defined for parametric roll and pure loss of stability. The IMO weather criterion is proposed to be the first tier criterion for the dead ship condition. The second tier criterion becomes an advanced research hotspot. Researchers in Italy and Japan proposed two different methods about how to simplify GZ curve. Two methods are based on the calculation of the probability of capsizing in certain conditions. Now, IMO determined using the draft of this two countries for the second tier criterion. According to the draft submitted by Italy and Japan, the main work is did as follows:Firstly, the paper studies the calculation method on the draft. Then it calculates the capsizing index based on two numerical computation methods submitted by Japan and Italy. Combing the calculation process and understanding the assumptions of the method.Secondly, a numerical calculation program is developed to calculate the capsizing index This paper calculates the C11 ship and CEHIPAR2792 to compare with the results gave by IMO.Thirdly, this paper collects a lot of particular of ship and makes a comparison of the stability performance of this vessels under two numerical computation methods.Finally, after a further research about two numerical computation methods, this paper presents some improvement measures in order to make the second generation intact stability criterion more reasonable.