Experimental measurements of hull pressures on fast displacement catamarans during motions in long-crested head-seas

Piezoresistive pressure transducers have been used to measure the pressure variations at six points on a catamaran hull moving in regular, long-crested, head-seas. Preliminary results demonstrate the feasibility of this experimental approach although a more refined experimental procedure may be required to obtain greater accuracy in the pressure measurements.The pressure measurements were carried out for one demihull spacing at two speeds in calm water and also in regular waves of differing wave periods. The mean pressures from both calm water and regular wave tests are presented along with the RMS variation from the mean during the tests in regular waves

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