engleski

Statistics of still water bending moments on double hull tankers

The paper deals with statistical description of the still water bending moments, which is important step in ship structural reliability assessments. Mean values and standard deviations of still water bending moments are calculated by analysing data from loading manuals of double hull tankers of different sizes. Loading conditions are grouped according to three characteristic modes of operation of tankers: full load, partial load and ballast. Partial loading condition is further divided into two sub modes: one giving hogging and the other one giving sagging bending moment at midship. Ballast condition is also divided in two separate sub modes: normal ballast and emergency ballast condition. Statistical properties for these modes and sub modes are compared and their dependency on ship size is investigated. Loading conditions giving maximum bending moments in hogging and sagging are identified and these values are compared to minimum design re-quirements of still water bending moments from Common Structural Rules. Statistics of differences between still water bending moments at departure and arrival are also analysed and presented in tabular and graphical forms. The paper ends with conclusions that may be useful for researchers dealing with ship structural reli-ability and also for ship designers applying Common Structural Rules.

tanker; structural reliability; still water loads

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