Comparative Analysis of High Speed Craft Hydrodynamic Characterization Algorithms

This work presents hydrodynamic characterization and comparative analysis of high speed crafts (HSCs). HSCs performance characterizing is a serious concern to Hydrodynamicists because of the wide variation of total resistance with hull-form, trim, draft and speed. Conversely, these parameters are not duly analyzed during design due to inadequate theories. Therefore, this research investigates total resistance, wetted surface and effective trim of four different HSC hull-forms. An interactive computer-program is developed based on Savitsky and CAHI algorithms, and the results compared against test-data. The analysis correctly predicts quantitatively the resistances of the four hull-forms at high speeds but with some discrepancies at speeds below 12 knots. The average standard-deviation for resistance predictions by CAHI = 4.69 kN and Savitsky= 6.13 KN. Also, the results indicate that the transition from bow-wetting to full-planing occurs at 12 knots, and beyond which the effective trim is fairly constant. Again, the wetted length-beam ratio (λm) drops rapidly from bowwetting speeds to a plateau at speeds >12knot where hydrodynamic lift prevails. Standard-deviations of λm by Savitsky's and CAHI are 1.07 and 1.41, respectively. In conclusion, model-predictors are reasonably in good agreement with measurement.