Dynamic analysis of launch & recovery system of seafloor drill under irregular waves

Based on the launch & recovery system of a seafloor drill, the nonlinear coupling mechanism among the movement of the ship, the umbilical cable, and the seafloor drill caused by irregular waves is investigated, and the dynamic model that considers the influence of the seawater resistance for launch & recovery system of seafloor drill is established in this paper. Under different sea state conditions, the movement of the seafloor drill and the tension of the umbilical cable are calculated and analyzed for the seafloor drill before entering water and at different water depths. The research results showed that there are significant differences in the movement of the seafloor drill and the tension of the umbilical cable for different stages. The seawater resistance has obvious inhibition effect on reducing the erratic fluctuation of the movement of the seafloor drill and the tension of the umbilical cable. The analysis results can provide theoretical guidance for the studying of heave compensation and the constant tension automatic control of the umbilical cable.