According to acting Premier Andrew Refshauge said the 270-degree side scan sonar would enable police to search for explosives more safely and effectively. “Underwater searching by police divers is often made risky by poor visibility, strong currents and adverse underwater obstructions,” he told SMH. “This advanced technology will help overcome these obstacles. It will be a valuable addition to the state’s counter-terrorism capacity.” Meanwhile a spokesman for Police Minister Carl Scully said the sonar scanner will enable them to identify specific areas of concern and go directly to that spot. Operationally the device is towed by a police boat and it sends out sonar signals that rebound off underwater objects and processed into images of the seabed and other surfaces. The images are viewed on an onboard computer. Sonar allows the device to work in low visibility and the system’s job will be to map the floor and sides of Sydney Harbour after which time the template will be compared with regular sweeps that will hunt for variations in the underwater landscape.