A Remoted Operated Vehicle, commonly referred to as an ROV, is a tethered underwater vehicle. They are common in underwater industries. ROVs are unoccupied, highly maneuverable and operated by a person aboard a vessel or ashore.
They are linked to the Rov Control Room by either a neutrally buoyant tether or often when working in rough conditions or in deeper water a load carrying umbilical cable is used along with a tether management system (TMS). The TMS is either a garage like device which contains the ROV during lowering through the splash zone, or on larger work class ROVs a separate assembly which sits on top of the ROV. The purpose of the TMS is to lengthen and shorten the tether so the effect of cable drag where there are underwater currents is minimized. The umbilical cable contains a group of cables that carry electrical power, video and data signals back and forth between the operator and the TMS.
Once at the ROV the electrical power is split and distributed between different components of the ROV.
However in high power applications most of the electrical power is used to drive a high powered electrical motor which in turn drives a hydraulic pump. The hydraulic pump is then used to power equipment such as torque tools and manipulator arms where electrical motors would be too difficult to implement sub sea.
Most ROVs are equipped with at least a video camera and lights. Additional equipment is commonly added to expand the vehicle’s capabilities. These may include sonars, magnetometers, a still camera, a manipulator or cutting arm, water samplers, and instruments that measure water clarity, light penetration and temperature.
ROVs may be "free swimming" where they operate neutrally buoyant on a tether from the launch ship or platform, or they may be "garaged" where they operate from a submersible "garage" or "tophat" on a tether attached to the heavy garage that is lowered from the ship or platform. Both techniques have their pros and cons; however very deep work is normally done with a garage.
There are five main classifications of ROV's
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Class 1: Observations vehicles.
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Class 2: Observation vehicles with payload capability.
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Class 3: Work class vehicles
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Class 4: Towed or bottom crawling vehicles
- Class 5: Specialized prototype or development vehicles.
ROV Systems vary from relatively simple camera platforms to very large complex machines capable of performing a variety of specialized tasks.
A typical ROV system will comprise the following:
- The vehicle
- A Launch and Recovery System (LARS)
- A power supply pack
- An operators console for control inputs
- Various display monitors
- Most importantly - The ROV PILOT Team
Technological development in the ROV industry has accelerated and today ROVs perform numerous tasks in many fields. Their tasks range from simple inspection of subsea structures, pipeline and platforms to connecting pipelines and placing underwater manifolds. They are used extensively both in the initial construction of a sub-sea development and the subsequent repair and maintenance.
While the oil & gas industry uses the majority of ROVs; other applications include Science, Research, Surveys, Archeology, Military and Salvage.
All ROV’s have one thing in common – they require a ROV Team to control and operate the functions that the System is capable of performing.
