Motion Analysis of Swath Vessel Using Strip Theory Based Program (Sedos) With Experimental Validation

The paper presents a study on motion analysis of SWATH vessel through a strip theory-based program (SEDOS) with experimental validation in waves. The concept of the SWATH has been developed over the last few decades, and today they are being constructed for a variety of different missions, relating to naval surveillance, oceanographic research and transportation of passengers or crew to floating installations such as offshore wind-farms. SWATH vessels are inherently more prone to larger pitching motions as compared with mono-hulls due to the characteristic slender water-plane area design feature. This paper presents the comparison of damping and restoring coefficient of SWATH and monohull of equivalent displacement. Also, pitch and heave motion responses of SWATH vessel using strip theory-based algorithm (SEDOS) with experimental validation are discussed. The results obtained from the analysis shows damping and restoring coefficient in pitch and heave for SWATH vessel are comparably less than equivalent displacement monohull. Pitch and hurl responses of SWATH without any appendages obtained from SEDOS and a result shows a reasonable agreement with experiments. However, the pitch response obtained in the analytical solution (SEDOS) seems to be over-predicting the response at resonance. The heave response at peak gives the reasonable match. However, there is a degree of scattering of the experimentally obtained values as compared to the analytical prediction.