The demand for utilization of ocean space such as quay wall in deeper sea area, embankment of reclaimed land for waste, reclaimed airport is increasing. To cope with this situation, safe and effective construction and maintenance of facilities in deeper sea area mainly port facilities are expected. One solution is mechanization of execution. However, the main problem is the lack of the vision by turbid water caused by construction work in the sea.
　We are making a research on the advanced remote control system for underwater backhoe by introducing bilateral control and haptic image to make the operation in unclear condition possible.
　Experiment was carried out by leveling unknown gravel terrain to a certain height by a land-use remote-control backhoe reconstructed for experiment.The operator was separated in the operator room from where the shape of gravel terrain and the posture of backhoe are invisible. However, the operator recognized the situation of operation by 3-D expression of haptic information and the feedback of reaction force.
　Experimental result is that error of leveling is within ±50mm. It is proved that the concept of proposed system is effective for the operation in turbid water in which the vision is hard to get.