Sensitivity analysis of the ultimate limit state variables for a tanker and a bulk carrier

Reliability analyses are performed for a SUEZMAX tanker ship and a HANDYMAX bulk carrier. Three loading conditions are considered for the bulk carrier, namely: homogenous loading condition, alternative hold loading condition and ballast condition. For the tanker ship only the full load condition is considered. After performing the reliability analyses, the importance of variables included in the ultimate limit state function for both Ships is calculated and compared. Since the ultimate sagging bending moment is the most critical capacity variable, the effect of modifying the structural design by increasing the deck plating by a certain factor while keeping the scantlings of the sides, bulkheads and bottom structure constant is studied. The influence of increasing the scantlings on the reliability and the sensitivity of the variables is Studied.