STAGGERED CATAMARANS: EXPERIMENTAL DATA AND FEASIBILITY STUDY FOR ENVIRONMENT FRIENDLY SERVICE

In the last years, displacement hulls for intermediate Froude numbers (Fn<0.6) have been studied at the Dipartimento di Ingegneria Navale of the Università degli Studi di Napoli FEDERICO II (DIN). Amongst the solutions tested, asymmetric multihulls seem to be quite interesting. Particularly, the scarce amount of experimental data available for staggered catamarans led to a research program in the towing tank, to evaluate the relation between total resistance of ship, stagger of demihulls and displacement. In this paper we will present the experimental data obtained in the first step of the carried out research. Particularly, hull performances evaluated for three Length to Displacement Ratios (L/1/3 = 4.62, 5.08, 5.76) and four staggers (6, 10, 20, 30 % of LWL) are shown for Fn < 0.5. The obtained results highlighted the suitability of the studied solutions for inland waterways and especially for urban services, where low environmental impact (wave wash and atmospheric pollution) is growing in social interest. The feasibility of the tested solutions was evaluated through a case study about passenger ferries in urban service. In the paper, general arrangements and cost considerations are presented