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The paper presents some results on investigations concerning development of a hybrid model for assessment of performance of the ro-ro ships in damaged conditions. The model is devoted towards assessing the performance of the damaged ro-ro ships at the preliminary stage of design. The key problems associated with preparing of such the model are associated with working out a method of assessment of the damaged roro ships performance, investigating all the phenomena which associated with the flooding process of the damaged ro-ro ships and preparing the model itself. Introducing the method of assessment of the damaged roro ships performance it has been assumed that there is a dependence between the arrangement of internal spaces of a ro-ro ship and flooding process. The major phenomena which have been decided to take into account when considering flooding of the ro-ro ships are the flooding understood as the flow of external water into the data damaged compartment, impact of the flooding water on the ship structure and damaged ro-ro ship motion. Knowing the damaged ro-ro ship motion characteristics in time domain it is relatively easy to assess the damaged ro-ro ship performance according to the heeling angle and assess the ro-ro ship design according to the data arrangement of internal spaces. The last research issue is to investigate if the proposed model may be appropriate tool for assessing the performance of the ro-ro ships in damaged conditions at the preliminary stage of design. The aim of this paper is to show how to incorporate the dynamics of the damaged ro-ro ships when assessing the ship performance and safety at the preliminary stage of design. The basic information on the model for estimation of the damaged ro-ro ship behavior during the flooding process is presented. The complexity of this model is shown depending on the approach applied to consider the flooding process itself. The model is devoted towards assessment of performance of the damaged ro-ro ships and it is still under the development according to a Ph.D. research at the Faculty of Mechanical Engineering Gdańsk University of Technology. [ABSTRACT FROM AUTHOR]

Abstract: Simplified mathematical models based upon semi-empirical regression formulae describing forces and moments acting on the hull during manoeuvres are commonly used for the preliminary evaluation of ship steering capabilities. Many semi-empirical regressions have been developed, and are broadly adopted, for the manoeuvrability prediction of single screw slow/medium speed ships. Their application for the study of twin screw vessels (cruise ships, RoRo ferries, megayachts, naval vessels, for which dedicated regression formulae are scarce) manoeuvring capabilities could lead to misleading results. These ships are usually characterised by different hull forms and more complex stern configuration due to the presence of appendages like skegs, shaft lines and brackets, which can strongly affect manoeuvrability behaviour. In this work a novel procedure to properly account for the particular geometric and stern appendage characteristics of these kind of vessels is described. A thorough analysis has been performed on a ship model equipped with 13 different stern appendage configurations and new formulae have been developed in order to describe accurately their influence on ship manoeuvring behaviour. [Copyright &y& Elsevier]