ROV-Based Automated Cable-Laying System: Application to DONET2 Installation

We developed an automated cable-laying system operated through a remotely operated vehicle (ROV). This system can automatically install a thin optical-fiber submarine cable at a rate that matches the ground speed of the ROV and adjust the amount of cable slack. The use of an ROV allows accurate and safe deployment of a thin optical-fiber submarine cable on the deep seafloor. The automated cable-laying system has been successfully used in installing the dense oceanfloor network system for earthquakes and tsunamis (DONET2) off the Kii peninsula in Japan. In our previous paper, we described the development process of the automated cable-laying system in detail. The current study focuses on the application in DONET2 installation and shows the practical advantages produced through automation. First, we overview the automated cable-laying system and then report on the successful application in DONET2 installation. The operating time and number of operators were distinctly reduced. Moreover, the physical and mental burden on the operators was relieved. In addition, several lessons learned during DONET2 installation are presented, and the unmanned cable-laying using an autonomous underwater vehicle is briefly discussed.