Remotely Operated Underwater Vehicles (ROVs) Information
Remotely-operated underwater vehicles (ROVs) are robots that complete functions underwater on behalf of a crew, located on the surface, with whom the ROV is tethered. These functions include: search/recover, inspection, equipment repair, scientific analysis, dredging/trenching, cable-laying, and surveying. This tether serves as the interface between the ROV and the ship and it provides the ROV with electric power and control commands, while providing the crew with video and data feeds. ROVs in deep or rough water will use a more robust umbilical cable and tether management system.
The abilities of ROVs are determined by what instruments are mounted to it. At minimum, an RVO will possess aquatic thrusters, a camera, and lights. Other tools commonly implemented on ROVs include: mechanical manipulators, sonar, magnetometers, various types of cameras, cutting/shearing tools, and other devices to measure characteristics of its environment. Electrical systems are outfitted in oil-filled water-tight or pressurized compartments. High-power applications and tools will receive power from an on-board hydraulic pump.
Generally speaking, there are five types of underwater ROVs and one class of autonomous underwater vehicle (UAV):
- Small electric ROVs are the smallest type of ROV. They do not utilize a hydraulic pump and are limited to depths of 1,000 feet or less. These ROVs can only be used for remote observation.
- High-capability electric ROVs also do not utilize a hydraulic pump, and its tasks are therefore limited to deep sea observation and illumination. Most high-capability ROVs are suitable for depths of 20,000 feet. It is primarily used by the scientific and military industries.
- The general class ROV is electrically driven, but may contain a primitive manipulator and sonar. A small, five horsepower electric motor is responsible for underwater locomotion.
- The work class ROV is the smallest iteration of hydraulic ROV. It is outfitted with a seven-function manipulator, a five-function grabber, and can be modified for specific applications. This type of ROV is commonly used in deep water drilling and construction applications. A 12,000-foot depth limit is normal, as is a 50 HP electric motor for propulsion.
- The heavy class ROV is the most capable type of industrial underwater ROV. These ROVs are outfitted with several multi-function manipulators and grabbers, as well as motors capable of generating several hundred horsepower. These ROVs possess the ability to lift 12,000 lb. from the sea floor to the surface, but are limited to working depths of 10,000 ft.
- Autonomous underwater vehicles (AUVs) are developed for military usage and have not yet been marketed to other industries. They primarily stalk enemy ships, protect harbors, and mine sweep. These vehicles do not require a tether or the extent of user manipulation needed for ROVs. AUVs are expected to become available for commercial applications once they have developed a niche in deep sea drilling and construction.
Video credit: Maritime Safety and Security Team Boston