Seakeeping and Added Resistance of a Fast Semi-Swath Ship

Multi-hull vessels, including SWATH vehicles, are interesting design solutions for a number of marine applications, from coastal ferries to workboats. Some hybrid and unconventional configurations, able to combine good quality of more classic designs, appear to be also attractive. This is the case of Semi-SWATHs, that merge the stern shapes of high speed catamarans with the bow shapes of conventional SWATHs. The aim of the proposed work is to go deeper into its seakeeping behavior also evaluating the added resistance. The analysis is carried out by means of a three dimensional Boundary Element Method (BEM), that makes use of a Rankine source distribution over the hull and the free surface. Incoming head waves only are considered in this study. Both the response amplitude operators of heave and pitch motions and the added resistance of the high speed catamaran are compared with available experimental data. The same analysis is carried out on the proposed Semi-SWATH vessel and results are critically discussed.