National Maritime Research Institute, in cooperation with several research organizations, carried out a study about developing a Deep-Sea Monitoring Robot System for investigation of sunken ships in deep sea. This system is consisted of a launcher and a small vehicle, and it has an advantage of both AUV and ROV. The launcher with a small vehicle descends by gravity, and controls its rudders for approaching to a target point. The launcher can correspond with the mother ship by using optical fiber cable. Just before reach the sea bottom, a launcher releases an anchor, launches the vehicle. The vehicle receives the command and transmits the image through the launcher by using the high-speed acoustic telecommunication system. We made a prototype of the vehicle, and a model of the launcher, and carried out the experiments in the deep-sea basin to confirm its efficiency experimentally. The high-speed acoustic telecommunication system was also completed, and was examined at sea. This paper will describe about the outline of these studies.
In January 1997, Russian superannuated oil tanker HAXOTKA, fully loaded with crude petroleum, met with a stormy weather and was damaged in the Sea of Japan. The hull was destroyed to two parts. The bow part drifted during few days, and was cast ashore. The coastline suffered immense damage of oil spillage. The stern part went to the sea bottom about 3000m in depth with a lot of crude petroleum. The Japanese Government dispatched the specialist team to accident ocean area to monitor the state of sunken ship by the ROV. Many drifting wires and ropes from a hull obstructed that the ROV approach for fear that its umbilical cable got entangled in them, so it was difficult to get the effective information.
