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A numerical model considering the seabed friction is developed to investigate the dynamic behavior of anchor cable in this paper. In the model, the anchor cable was divided into hanging and lying parts. The governing equations of hanging and lying anchor cables were established respectively based on finite difference method and coupled according to the boundary conditions. The coupled equations of anchor cable were solved by Newton iteration and the static anchor cable parameters used for the initial values were confirmed by double bisection method. To illustrate the reasonability and validity of the model, several simulations of vessel sway in wind with different time and space step sizes and different seabed friction coefficients were presented. The simulation results show that anchor cable snap load is 3–5 times of average tension, the variation of anchor cable bearing is 2 times of ship heading, and the sway amplitude of the ship's center of gravity is about one times of ship length. Compared with the experimental data, the model and algorithm in this paper can successfully provide the realistic prediction of the dynamic tension and configuration of anchor cable, and can be used as a reference for anchoring operation. Farther, this paper found out that the normal seabed friction coefficient has considerable impact on the cable tension. [ABSTRACT FROM AUTHOR]

To determine the parameters of bridle towed systems in preliminary design and describe the configuration and dynamic behavior of bridle cables during tow-ship changes its speed and course, a tug-cable-barge coupling motion model for bridle towed system is proposed. The governing equation of towing bridle was established based on finite difference method and the six-degrees-of-freedom equations of motion for tug and barge were adopted according to the MMG modeling theory. The dynamic coupling boundary conditions for bridle towed system are derived. The steady- state motion parameters of towing bridle were confirmed by double bisection method. The equations of towing bridle are solved by Newton iteration method. Tug and barge motion equations are solved by Runge-Kutta method. The computing results indicate that the model and algorithm in this paper can be used to predict the configuration and dynamic behavior, and determine the parameters in preliminary design of bridle towed systems. [ABSTRACT FROM AUTHOR]

In addition, the third sentence in the first paragraph [ABSTRACT FROM AUTHOR]