Automated processing of free roll decay experimental data

This work presents an efficient numerical and modular approach to assessing viscous roll damping coefficients from free decay tests. In order to reduce the time consumed during analysis, numerical pre-processing of the data without visual inspection is suggested. The method involves breaking down multiple decay motions recorded in a single time series, numerically determining the beginning and the end of valid decay motion, eliminating the outlying data from the experimental analysis and obtaining the linear and non-linear roll damping coefficients. None of the pre-processing steps depend on each other and they can be used separately in a modular structure. The process is exemplified using decay test samples of a fishing vessel. To use these analysis results in numerical simulations that extend beyond identical conditions with the experiments, a 3D surface approach is examined. The surface also reveals the effect of speed on the coefficients obtained from the sample set.