Research On The Draft Vulnerability Criteria Of The Pure Loss Of Stability Of Ship

Ship’s stability is one of main parameter in the process of ship design. And research about it is very popular. At present, the worldwide used stability criteria is the<2008intact stability criteria>, But more and more ship’s accidents due to loss of the stability shows that a ship which though meets the demand of the intact stability criteria, a stability loss accident could happen So it shows that criteria which is based on the hydrostatic theories and the experience couldn’t meet the needs of all the ship styles such as PoRax ship,also the stability problem when ship is sailing in the waves. On the other hand, IMO and others ship professors intend to apply the hydrodynamics theory to the ship stability criteria. Based on the two points,IMO is on the work of Second Generation Intact Stability Criteria. Pure loss of stability is one of the five failure modes. And the study on its draft vulnerability criteria will provide some basis for the new stability criteria, and promote it.The main works of the article is study on the draft criteria of pure loss of stability vulnerability criteria and its program development. The contents are as follows:(1) GM and GZ calculation. Give a brief introduction of GM and GZ’s solution in still water. And for the GZ curve, give introduction to its character value. GZ’s calculation in waves is based on Froude-Krylov assumption.(2) wave conditions. The article gives two different ways to convert random waves into regular waves. The two different methods both make use of IACS Rec.34. Then, introduce how to definite the wave length, wave height and its weight factor.(3) the draft vulnerable criteria of pure loss of stability and its program development.The article firstly analyzed the GZ’s change low in wave and introduced the failure mode’s possible scenario and its draft vulnerable criteria. Then, take on the program development using Visual Basic6.0. Cl1container ship is calculated to verify the program.(4) Sample calculation and comments on draft vulnerability of pure loss of stability. The article used the system calculated the NO.l sample ship and NO.3sample ship of LiaoNing province and made comments.