In this paper, the discrete event/discrete time simulation of the block erection by a floating crane is performed for the purpose of estimating the motion of the floating crane and the block and also calculating the tension of the wire rope between the two. At this time, the dynamic equations of motion of the floating crane and the block are set up for considering the 6-degrees-of-freedom floating crane and the 6-degreesof- freedom block based on multibody system dynamics. The nonlinear terms in the equations of motion are considered. In addition, the nonlinear hydrostatic force, the linear hydrodynamic force and the wire rope force are considered the external forces. Finally, we analyze the engineering effects of erecting the block by using the floating crane.
A floating crane is a crane-mounted ship as shown in Fig. 1. and is used to erect or to transport heavy blocks or cargos. Because a floating crane in shipyards is a barge ship, a flat-bottomed boat, it is not self-propelled and must be towed by tugboats. A floating crane is able to lift about 3,600 tons of weight by buoyancy force as well as by the force of structural stiffness. For improving the efficiency of production in shipyards, the floating crane is used more often today. The stability of the floating crane is important because it is operated in the sea. Now, the operation by the floating crane does not allowed in the heavy sea. In addition, new methods of operation the floating crane are avoided, if the stability is not guaranteed. So, the engineer planning these methods of operation must estimate the dynamic motion of the block suspended by the floating crane and calculate the tension of the wire rope between the floating crane and the block. At this time, the following facts should be considered.
