Remotely operated vehicles (ROVs)
A Remotely Operated Vehicle (ROV) is a tethered underwater robot, distinguishing it from remote control vehicles that operate on land or in the air. ROVs are unmanned, highly manoeuvrable and controlled by an operator(s) aboard a vessel. They are linked to the ship by a cable known as the umbilical, a group of cables that carry electrical power, video and data signals back and forth between the operator and the vehicle.
ROVs vary in shape, size and capability depending on their task. Together with their monitoring and control equipment, launch and recovery systems, umbilical controls and winches they are a complex array of electrical, electronic, hydraulic and mechanical systems.
Many ROVs operated in the oil and gas industry are designed to dive to 3,000m, whereas specialised science ROVs can operate in the deepest of oceans, 6,500m and beyond. Some marine trenches extend to around 11,000m. Most ROVs are equipped with at least a video camera and lights. Additional equipment is commonly added to expand the vehicle’s capabilities. A science ROV’s instrumentation suite may include sonars, magnetometers, a still camera, manipulators, water samplers, and instruments that measure water clarity, light penetration and temperature.
Why do we use ROVs?
ROVs enable intricate survey of the seabed. They also allow us to take precision samples and to conduct experiments at water depths unreachable by human divers due to the water pressure. Although manned submersibles exist that can transport humans to these depths, ROVs are a more compact, portable and practical alternative without the human risk element. An ROV can be manoeuvred precisely with its thrusters (propellers). Through its eyes (cameras), the manipulators (hands) can be used to select and recover small, delicate objects more precisely than any other sampling system. Scientists can see the undisturbed area from where samples are selectively taken, providing them with a better understanding of habitats and structures. Complex in situ experiments can be achieved maintaining the environmental conditions and minimising sample damage caused by recovery to the surface.
The NOC ROV facility
The science ROV named Isis is a work-class vehicle capable of descending to a depth of 6500m. The vehicle is supported with containerised control room, workshop and spares storage, with a Launch and Recovery System (LARS). Suitably sized and dynamically positioned (DP) ships of opportunity allow the system to be freighted and operated around the world.