Design Features of an Unconventional Passenger Vessel with Low Environmental Impact

The paper refers to an unconventional passenger vessel which matches hydrofoil and SWATH principles in order to achieve high transfer speed, low environmental impact and reduced wave washing phenomena. This innovative, hybrid vessel, called ENVIROALISWATH, should be able to provide high performances, manoeuvrability and controllability typical of hydrofoils and, at the same time, good sea keeping qualities and low installed power, typical of SWATH solution. The design has been developed through a joint research program between Rodriquez Cantieri Navali S.p.A of Messina and the University of Genova. In this paper the main phases of the structural design are described. At first a preliminary scantling of the main cross section was performed, applying the regulations for High Speed Craft (HSC) of three different classification Societies: Registro Italiano Navale, American Bureau of Shipping and Det Norske Veritas. Preliminary studies, on simplified numerical models, are also performed to evaluate the mutual interaction between the hull and the submerged structure. The main information have been collected in order to setup a finite element model suitable to simulate the behaviour of the structure as a whole. Starting from this model subsequent implementations have been carried out improving the investigation of stress and strain distributions. Local and global effects have been considered. For the numerical detailed investigation the FEM code Maestro has been used for both complete model and structural detail analysis.