Effects of uncertainties in loading conditions of bulk carriers on hull girder still water loads

This paper reports a study on the uncertainties in assessing loading conditions of handy size bulk carriers. Loading conditions and the corresponding hull girder still-water loads are important for the safety of bulk carriers. Unfortunately, statistical studies on this topic remain very few, partly because of the difficulty in fully understanding the impact of loading/unloading operation process and partly because of intrinsic uncertainties in measuring cargo loading conditions data. Three handy-size bulk carriers were investigated and their actual loading conditions, spanning several voyages in 22 months, were collected. Statistical analyses of the collected data resulted in an estimate of the uncertainties in the loading/unloading process. Based on these analyses, probability distribution models for weights in cargo holds, water ballast tanks, fuel tanks as well as consumable tanks are proposed best fitting the collected data; hull girder still water loads statistical distributions are also obtained. It is expected that these analytical models can be used in structural reliability analyses that require the definition of uncertainties of loading conditions and of resulting still water loads.