Seakeeping Characteristics of the XR-5, A High Length-Beam Ratio Manned Surface Effect Testcraft:III. Results of Random Wave Experiments Investigation of Linear Superposition for Ship Motions and Trim and Draft in Random Waves,

摘要

Motion responses derived from model experimental results in regular and irregular head waves for the XR-5 high length-beam ratio surface effect ship are presented. Frequency response functions for pitch, heave, relative bow motion, heave acceleration and bow acceleration were computed from the random wave experiments and are presented herein. Comparisons are made with responses derived from regular wave experiments. The results indicate that the rigid body motions are reasonably linear for the Froude numbers and sea conditions investigated. Nonlinear effects that increase with the severity of the sea state are evident in the accelerations. In addition, the motion of the stern seal with respect to the relative motion at the stern is presented. These responses are generally linear although some nonlinear effects appear with increasing Froude number. Probability distributions for the double amplitude of wave height, heave and pitch are presented. Comparisons are made with Rayleigh probability distributions based on the variances of the sample data and on the minimum Chi Square estimators computed from the distributions. (Author)