Experimental and numerical analysis of installation process using dual floating crane vessel

Abstract

In this study, installation process of pipe-type structure is conducted experimentally and numerically using dual floating crane vessels. Because installation structure is a long pipe, two crane vessels are required for the installation process. Two crane vessels are facing each other holding each end of the installation structure. In the experiment, two vessels are moored by soft spring, and various wave condition are considered. Measured items are 6DOF motions of two vessels and pipe, wire tensions at the end of the crane and mooring line tensions. In numerical analysis, motions of crane vessels are based on floating body dynamics using convolution integral, and crane wire is treated as simple spring. Installation structure is assumed as a rigid body with 6DOF motion. As in the experiment, numerical simulations in regular wave are performed. Characteristics of vessel motion and wire tension according to wave conditions are checked, and computation results are compared with experimental data. It was checked which frequency range is critical by reviewing the motions of dual crane vessels, and near the yaw motion resonance point of the pipe-type structure has the worst effect on crane vessel’s motion. Copyright ？ 2018 by the International Society of Offshore and Polar Engineers