A remotely operated underwater vehicle, also referred to as ROV, is an underwater vehicle which is usually tethered. The unoccupied vehicle is similar to a robot, which is fitted out with sensors and sampling tools to collect various types of data. A network of cables is utilized to establish a connection between the operator and the remotely operated vehicle, which would enable the proper movement of the ROV.
An underwater ROV is well-equipped with modern technology and consists of a lighting system and a video camera, to record a better subaquatic panorama and contribute to geology education and sea life learning. With the incessant development in the arena of technology, latest technical concepts are being imparted to remotely operated vehicle in order to amplify its original capacities to a greater extent. Extra machinery can comprise of a static camera, a water sampler or even a manipulator.
Moreover, a remotely operated underwater vehicle can also incorporate advanced instruments for an appropriate measurement and evaluation of current temperature, penetration of light and the water clarity.
ROVs or underwater robots were primarily invented to serve an industrial purpose, regarding regular pipeline inspection (both interior and exterior) and to conduct structural testing methods on certain platforms,from various offshore locations. The underwater ROVs are even useful for the exploration of oceanic water. The ROVs cater to the needs of innumerable science expeditions, and several educational programs at aquaria.
Categorization of ROVs
The underwater ROV’s can be distinguished into classes by evaluation of their weight, power, abilities and of course their sizes. The Micro ROV is small-sized and weighing below 3kg. These attributes enables the ROV to explore minuscule cavities or pipeline cracks, which is physically impossible for a diver to achieve. On the other hand, the typical Mini underwater ROV have a standard weight of around 15kg and it takes just one person to easily operate it from a boat, and carry out an underwater expedition.
The micro and mini categories of remotely operated vehicles can be termed with an alternative “eyeball” as they do not participate in intervention undertakings. The General ROV type is usually below HP (propulsion) and comprises of three finger manipulators, like in the old RCV 225. These are specially built to aid in light survey tasks as these usually bear a sonar unit. The standard underwater depth is around 1000 meters, but one ROV has been upgraded to even traverse till 7000 meters.
The Light work class remotely operated vehicle is generally below 50 HP and can support several manipulators. These ROV’s allow a maximum working depth of 2000 meters.Polyethylene, which is a kind of polymer, is used in construction which varies from the typical aluminium alloys or stainless steel.
The Heavy workclass machine supports below 220 HP with two manipulators, and can achieve a depth of 3500 meters. The Trenching ROV offers a 200-500 HP range and can be utilized till 6000 meters.
Preparation and Launching of ROVs
The size range of a remotely operated vehicle is very impressive, as it may vary from a small bread box to a minor truck. The preparation of the launch of an underwater vehicle can be very simple to operate as the robot can be merely dropped into the water from the vessel. The recovery procedure may involve big windlasses to uplift the robot from the water. Generally, A-frames are available to swing over the ROV safely onto the deck. Sometimes, extra structures called “garages” are present which are lowered to the rear end. These “garages” can act like a temporary yet secure den, and the ROVs can return once the expedition gets over. The occasional excursions carried out by employing the remotely operated vehicles are considered to be much safer compared to the usual diving expeditions which can lead to physical injury or even death.
A remotely operated underwater machine can prove to be highly efficient when it comes to dealing with a submersible, as the cutter blades or the manipulator arm can come in handy while rescuing the submersible if it is stuck and unable to move freely. Another drawback of submersible ventures is that bad weather conditions can prove to be a major hindrance, whereas a remotely operated vehicle can remain unaffected. As an added utilization, a research can initially submerge the ROV into the water to explore the detailing of the particular underwater site and then decide if it is safe enough to send a submersible.
Amongst well-known underwater ROVs, the Ventana runs on hydraulic power and can traverse to a depth of 1850 meters. The Ventana is manipulated from the RN Point Lobos ship deck. On the other hand, the MBARI franchise has purchased the ROV Doc Ricketts way back in 2008, which offer an incredible capacity of going deep down till 4000 meters. This remotely operated vehicle has undergone constant upgradation, ever since. The Doc Ricketts served as a magnificent replacement of the earlier ROV Tiburon, which could also travel down 2.5 miles.
These special submarines have enabled easy exploration of several deep sea gas and oil reserves, than before. Many oil reserves were hard to locate by the divers and hence caused a major commercial setback. Interestingly, the indefinite locations famous shipwrecks like the RMS Titanic, USS Yorktown, SS Central America and the Bismarck have been discovered due to some help from the ROV industry. In the case of SS Central America, the remotely operated underwater vehicle has also been able to retrace and fetch some important materials from the sea floor of the shipwreck.
A huge setback of a remotely operated underwater vehicle is that it lacks human presence which makes it difficult for executing the visual surveying down in the water. The vehicle remains attached to the main boat above water through intricate wiring and this leads to a restriction of free movement.
References: noaa, oceaneering, rov
Image Credits: wikipedia, astro