Study of the Hydrodynamic Performances of a Trimaran Ship for Fast Transportation

The increasing demand for high speed in the ferry market has induced a great number of applications which range from deep-V monohulls to different kind of twin hulls (Catamarans, SWATHs, …). Contemporarily, several studies appeared in the literature about the hydrodynamic advantages of trimaran hulls and some application examples have also been given. In this context, the Universities of Ancona, Genova, Napoli and Trieste, in the frame of an interuniversity project supported by The Ministry of University, Scientific and Technological Research, undertook the study on the application of the trimaran concept to high speed commercial vessels, as an alternative to the current design practice. After an initial survey of the market of high speed commercial vessels, the study has focused on passenger fast ferries, suitable for service in the Mediterranean and Northern Seas. The target mission profile and carrying capacity requirements have been chosen according to some existing solutions in order to allow a direct comparison of performances. The research project is now at the model testing phase in order to assess both resistance performances and sea keeping characteristics. Resistance tests have been performed in the towing tank of the University of Genova while the seakeeping and the dynamic stability, including the behaviour in beam waves and the mathematical modelling of roll motion, are under study at University of Trieste on an experimental basis. In this paper, results of a systematic series of towing tank tests conducted on different configurations are presented together with a preliminary assessment of dynamic stability in waves. The towing test matrix included a total of 12 configurations obtained by three longitudinal outriggers positions and four transversal outrigger position.