IMDEX ’97 International Maritime Defence Exhibition & Conference, Greenwich-London, October 1997 Design Aspects and Applications of Deep-V Hull Forms to High Speed Crafts Stefano Brizzolara & Luigi Grossi Hydrodynamic and Acoustic Department FINCANTIERI Naval Shipbuilding Division, Genova - Italy Abstract: The recent increase of the demand for high speed which is being experienced especially in the market of commercial ships, has given most shipyards the opportunity to improve and employ their know-how in the design of fast vessels. The combined low powering and good seaworthiness requirements, which are of vital importance in fast transportation, have stressed the research and development of unconventional hull forms and determined the growth of new ships typologies. Nowadays talking about vessels of more than 4000 tons of displacement which can sail in calm seas at more than 40 knots and grant good seakeeping and speed performances also for sea states higher that 4, is common. This is the field where hard-chine monohulls and multihulls of various types have found their specific range of applicability. Looking into the future, speed limits greater than 50 knots at the same cargo capacity are awaiting the market maturity and extensive research activities are being carried out at present by shipbuilders. For these requirements other types of ships, such as SES, seems to be more suitable. In this paper an assessment of the newest unconventional hull types which are currently under construction or object of research projects in FINCANTIERI, is reviewed, focusing the attention either on the methodology and tools employed in the design phase, either on the peculiar hydrodynamic characteristics of each hull type. The use of the modern computational fluodynamic tools (CFD) in the preliminary stage of the project is useful to reach a satisfying solution which can fulfill the specifications. The validity and effectiveness of these types of computer simulation programmes are discussed on the base of the results achieved in the application on the latest designed ships which were tested in model scale and/or built. Some criteria on the evaluation of the data which such programmes can provide is also included. The powering, seakeeping and manoeuvring performances of Deep-V monohulls over conventional round bilge hulls are analysed and critically discussed within their application to fast ferries. Some interesting full scale results will be presented as well, with the aim to validate the computational design methods.