engleski

The Assessment of Ship Hull Weight Using Tolerances of Rolled Steel Plates and Sections

The paper considers the assessment of uncertainties of the ship hull steel weight with respect to uncertainties of built-in steel products. First, a general procedure for worst-case approach based on tolerances is presented. A review of tolerances on rolled plates and sections provided for shipbuilding, according to the Classification Societies, international standards as well as the tolerances defined by the steelworks, are given herein. Using tolerances of plates and sections, the deviations of weights of the hull, structural parts and substructures from the nominal weights are assessed by application of the worst-case approach. Rates of changes of weights with respect to basic scantlings are introduced. Additionally, the influence of the geometrical tolerance in production, like cutting, welding and other workmanship, on the weights of the ship hull has been checked. Five typical stiffened panel types, most frequently used in the ship construction are subject to weight deviation analysis. Next, a typical bulk carrier midship section has been investigated from weight deviation point of view. Finally, for a bulk-carrier built in Croatian shipyards, a review of overall ship hull weight distribution, according to plate thickness and dimensions of sections as well as the maximal possible deviations of the nominal weights due to tolerances, are summarised.

ship hull; weight; assessment

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