Ride Severity Index - A New Approach to Quantifying the Comparison of Acceleration Responses of High-Speed Craft

This paper presents a simplified approach to quantifying the comparison of acceleration responses of high-speed in rough seas. Statistical acceleration values, used to characterize craft seakeeping responses, including average of the highest 1/3 rd , 1/10 th , and 1/100 th peak accelerations and the rootmean-square (RMS) acceleration, are used to define the relative Ride Quality Index (RQI). The paper first summarizes an unambiguous computational procedure for multiple investigators to calculate similar acceleration values. It then explains the theory and rational for relating statistical acceleration ratios to an indication of potential damage, whether due to cumulative wave impacts or single severe slam events, that can be used in comparative assessments of structural integrity, equipment susceptibility to malfunction, or personnel comfort and safety. Example ride quality comparison plots and computed values of RQI are presented to illustrate the simplicity of the approach, and to demonstrate the ability to quantify what heretofore has relied primarily upon the subjective experience of operators.