Dynamic Line Force and Oscillatory Motion of a Vessel Being Winched down in Ocean - Two Computer Solutions

摘要

Two computer programs written in Fortran language were developed, one to estimate the line force response to waves of a surface buoy with taut mooring, and the other to estimate the oscillatory motions of a submerged vessel moored in an ocean current. A mechanical impedance approach was used to obtain transfer functions of taut buoy mooring systems. Nylon rope was found superior to steel wire rope for reducing the wave-induced dynamic line forces in a selected example. The effect of sub-surface current on the mooring tension, buoy equilibrium position and the frequency of oscillation were calculated by catenary equations and pendulum analogy. The static line force in mooring was found to increase greatly as the horizontal current increases. (Author)