Cable Laying Using an ROV

AbstractA remotely operated vehicle (ROV) can install submarine cables along a planned route accurately, thereby deploying cabled seafloor observatories at the intended locations. In this study, we developed an ROV-based cable-laying system. Its manual and automated versions have been successfully used for the installation of the Dense Oceanfloor Network system for Earthquakes and Tsunamis (DONET). The automated cable-laying system shows many advantages; for example, the cable-laying speed increased by approximately 0.1 knot from 0.5 knot, and the number of operators was reduced by half. Thus, the physical and mental burdens on the shipboard members including ROV operators were relieved. In this paper, we share our experiences when laying cables using an ROV during DONET installation. First, the issues that should be addressed to complete a successful cable-laying operation are discussed; subsequently, our manual and automated cable-laying systems are introduced. Then, the observations made during field operations for DONET installation are presented, which provide useful tips for developing an ROV-based cable-laying system.