Experimental measurements of the seakeeping characteristics of fast displacement catamarans in long-crested head-seas

The report describes an experimental investigation into the seakeeping properties of catamarans. Three geometrically similar hull forms were tested covering a range of Length:Displacement ratio from 7.4 to 9.5. The hulls are of round bilge transom stern form and are based on the NPL round bilge series. A number of hull configurations, including monohull and two catamaran demihull spacings, were tested at three Froude numbers (F subscript n = 0.2, 0.53, 0.8) and over a range of wavelengths. Long-crested head-seas were used for all experiments. Measurements of heave, pitch, vertical acceleration at two stations and added resistance in waves were made. Response functions have been calculated from both regular and irregular wave experiments