Examination of the transverse stability of fishing vessels by residual energy

In this study, the transverse stability of eight fishing vessels is analyzed by determining their residual energy for different sea and weather conditions. For this aim, the single degree of freedom rolling motion is modeled by a nonlinear differential equation including steady wind and gust moments. In the method of residual energy, firstly the nonlinear equation is integrated for a bounded area of initial conditions. Second, capsizing initial conditions and their energies are determined. Finally, the smallest energy of the capsizing initial conditions is chosen as residual energy which shows the width of safe domain of fishing vessel. If it is equal to zero, there is no safe domain of fishing vessel. From the results of this study, it can be concluded that the capsizing probability of the fishing vessels increases dramatically by increment of wind forces and decrement of beam.