Qwik Connect
ROV classes Observation Observation with payload Work class Bottom crawling
ROVs: The Workhorse of Subsea Science and Exploration
Typical work-class ROV systems provide power levels ranging from 100 to 200 horsepower, and even as high as 330 HP. Trenching vehicles are equipped with 1500 HP electrical power for impressive thrust in either vertical or horizontal directions. In the past, ROVs have operated at 120V, but due to growing power requirements the industry is now adopting 270 and 240 VDC full wave rectification of 120/208 three phase AC for manned submersibles. Small inspection-class ROVs continue to operate in the 100–130 VAC range.
Small unmanned submersibles called “marine remotely operated vehicles” or ROVs are deployed throughout the oil & gas industry—and in other industries such as scientific research, fisheries and aquaculture, oceanography, underwater archaeology, ocean exploration, and military/ defense—to perform inspection, repair, and maintenance functions in water too deep or too dangerous for divers. ROVs service sea floor drilling and processing operations with capabilities as diverse as trenching and drill support. The various classes of ROVs are distinguished by their size, maneuverability, methods of propulsion. Regardless of class, all ROVs are cable connected (tethered) to their support platform. In addition, ROVs share two key characteristics: a subsea-to-topside visual feed (typically an HD/SD TV which provides real-time or slow-scan viewing) and the ability to rise or submerge subsea. Autonomous underwater vehicles (AUVs) are a far different class of submersible, and do not employ a support tether.
During operation ROVs are linked to a host ship by a neutrally buoyant tether or, 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, in the case of 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 as needed so that the cable drag effect of underwater currents is minimized. The umbilical is an armored cable that contains a group of electrical conductors and fiber optics that carry electric power, video, and data signals between the operator and the TMS. Some umbilical tethers are equipped with pneumatics to power work-class ROV equipment. Where used, the TMS then relays the signals and power for the ROV down the tether cable to power sonars, magnetometers, still cameras, manipulators, water samplers, cutting arms, or scientific instruments that measure water clarity, temperature, density, sound velocity, and light penetration.
<ROV with tether management system
Qwik Connect n October 2016
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