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Underwater vehicles
| Submersible work platforms that can be operated either remotely or by an onboard crew. Unlike military submarines, which are essentially submerging ships, submersibles are not self-contained. All submersibles require some sort of surface-support vessel. |
History
| Perhaps the earliest underwater vehicles were the seventeenth-century ambient-pressure diving bells used mostly for recovering items from shipwrecks, in which the workers were in a dry environment but exposed to full depth pressure. Development of practical,crewed underwater vehicles began before World War I, with 1-atmosphere surface-tethered diving bells and armored diving suits. Both were intended to perform salvage tasks. Some of the bells could go to depths of several hundred feet and were equipped with external lights and a variety of tools. |
| Armored suits were one-person submersibles in the general shape of a diving suit. Depth capabilities to 700 ft (210 m) were possible since the operator/diver was not exposed to sea pressure. Bottom time at the work site was greatly increased over conventional diver capability. Problems with the flexibility and watertight integrity of the suits' articulating joints limited use of these devices prior to World War II. |
| In 1930, the United States scientist William Beebe and engineer Otis Barton developed the Bathysphere (“deep sphere”), a thick-walled steel ball lowered into the sea on a steel cable. The interior provided sufficient room for two crew members and their equipment. Two quartz glass windows permitted outside viewing and photography. The cabin had a third window opening but that window was broken during installation and was covered with a steel plate. The Bathysphere made 32 dives from 1930 to 1934 at Bermuda, ending with a dive to 3028 ft (910 m). Beebe's classic book, Half Mile Down, tells the story of this pioneering deep-sea research program. |
| In 1950, an improved bathysphere, the Benthoscope, was developed by Barton. It was successfully tested off California to depths of 4500 ft (1350 m), but made few working dives. Japan developed the Kuroshio for oceanographic research in the early 1950s. Retired in the 1960s, it was capable of diving to 650 ft (200 m). This was the world's last operational bathysphere, although the diving bells of today are not much different in concept. |
| It was not until 1948 that the first practical untethered underwater vehicle was tested: the bathyscaph (“deep ship”) FNRS-2, invented by Swiss physicist Auguste Piccard. It was an underwater free balloon, with buoyancy provided by lighter-than-water aviation gasoline contained in a large steel float (balloon). A thick-walled spherical cabin for two crew members was suspended beneath the float. The float moved vertically by adding weight (seawater) or losing weight by dropping steel ballast pellets. Small electric motors fitted with propellers provided limited horizontal and vertical movements. |
| From 1950 to 1978, the French Navy developed and operated bathyscaphs FNRS-3 (1953) and Archimede (1963). In 1953, Piccard built his last bathyscaph, Trieste, which was sold to the U.S. Navy in 1958. In 1960, a Navy expedition took Trieste to a depth of 35,800 ft (10,700 m) at Challenger Deep near the island of Guam in the western Pacific, the deepest place in the world ocean. After the original Trieste's retirement in 1963, the Navy built two improved bathyscaphs called Trieste II. Both had a maximum depth capability of 20,000 ft (6000 m). |
| Archimede was retired in 1978. It was the last crewed submersible in the world capable of diving to the deepest place in the sea. Four years later, Trieste II was retired; it was the last operating bathyscaph in the world. This type of deep submersible vehicle had served 35 years; much of this time, it was the only way to work in the deep ocean. |
| These retirements were not the end of deep-diving submersibles. New construction materials and technologies have provided the means for building submersibles that are much smaller, less costly to operate, and safer than the bathyscaphs. |
| During the 1960s and early 1970s, divers and crewed submersibles dominated the underwater scene. However, new types of vehicles were under development in research laboratories during this time. A major development was the remotely operated vehicle (ROV), a tethered vehicle controlled from the surface of the sea. The autonomous underwater vehicle (AUV), essentially an underwater robot, was also under active development but its maturity would take much longer than the ROVs. |
| Almost all early submersible designs, technologies, and operational techniques were developed by navies, the U.S. Navy in particular. Military missions and related science needs were the primary forces driving research on underwater operations during this period. By the mid-1970s, civil applications were stimulated by the steep oil price increases worldwide. This led to increased offshore oil and gas exploration and production activity. Opening new resource areas, such as the North Sea, accelerated development of better tools and techniques for conventional deep-sea divers. Beginning in 2004, this pattern of technological demand began repeating itself as oil prices soared again. Exploration and production now go to depths as great as 2 mi (3 km), where only submersibles can do the undersea work. See also: Diving; Oil and gas, offshore |
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Types
| Underwater vehicles can be grouped into three general categories: crewed deep submersible vehicles (DSVs), tethered remotely operated vehicles (ROVs), and untethered autonomous underwater vehicles (AUVs). In recent years, the term “human occupied vehicles” (HOV) has sometimes been substituted for DSV. |
| There are also hybrid vehicles, which combine two or three categories on board a single platform. Within each category of submersible, there are specially adapted vehicles for specific work tasks. These can be purpose-built or modifications of standard submersibles. |
Crewed deep submersibles
| Since the late 1950s, over 200 crewed submersibles have been put into service worldwide. By 2005, about 75 were operational; the majority support tourist operations, with marine science applications being the second greatest. There are five types of these vehicles: 1-atm untethered vehicles; 1-atm tethered vehicles, including observation/work bells; atmospheric diving suits; and diver lockout vehicles. While they differ mainly in configuration, source of power, and number of crew members, all carry a crew at 1-atm (102-kilopascal) pressure within a dry, pressure hull. The fifth type of crewed submersible is the wet submersible, in which the crew is exposed to full depth pressure. |
| The purpose of the DSV is to put the trained mind and eye to work inside the ocean, often referred to as in situ work. The earliest submersibles had very small viewing ports fitted into thick-walled steel hulls. In the mid-1960s, experimental work began on use of massive plastics (acrylics) as pressure hull materials. Today, submersibles with depth capabilities to 3300 ft (1000 m) are being manufactured with pressure hulls made entirely of acrylic. Essentially the hull is now one huge window. |
1-atmosphere untethered vehicles
| These are submersibles that carry 1–64 occupants at 1-atm pressure (Fig. 1). The submersible is battery-powered (though fuel cells have been tested), free-swimming, and capable of limited horizontal travel across the seabed. |
Fig. 1 Two-person deep submersible vehicle Deep Rover with all-acrylic pressure hull. (Deep Ocean Engineering, Inc.)
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| The four deepest-diving crewed submersibles are operated by France (1), Russia (2), and Japan (1). Three can dive to 20,000 ft (6000 m), and Japan's Shinkai 6500 can go to 21,323 ft (6500 m). Though the deepest place in the ocean is about 36,000 ft (11,000 m), there is no crewed vehicle at present that can reach this depth. However, a submersible designed to operate at 20,000 ft can reach 98% of the sea floor worldwide. Therefore, designing for two-thirds the maximum depth of the ocean is a reasonable engineering and cost goal. |
| In 2005, two programs began constructing new crewed submersibles for marine science work. At the Woods Hole Oceanographic Institution, a 21,323-ft (6500-m) vehicle is being designed to replace the 13,000-ft (4000-m) Alvin, built in 1964, and in the Peoples Republic of China a 22,460-ft (7,000-m) crewed submersible is being built. |
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Observation/work bells and 1-atm tethered vehicles
| These carry a crew of two or three at 1-atm pressure. Power is supplied by batteries, or from the surface through an umbilical cable. The vehicles (Fig. 2) always operate with a lift cable from the surface and are designed for panoramic viewing and a high degree of maneuverability and station-keeping, and are fitted with manipulators (external mechanical arms and hands) for work tasks. Many of these tethered vehicles are capable of limited maneuvering in three dimensions. They are primarily designed for performing manipulative work around underwater structures mostly in support of offshore oil and gas development. Maximum depth is 2300 ft (700 m) [Fig. 3]. |
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Atmospheric diving suits (ADS)
| These are designed for a one-person crew at atmospheric pressure. In operation, they are similar to the 1-atm tethered vehicles. In this case, the vehicle is anthropomorphically configured (Fig. 4) and power for maneuvering is manual or electrical via a surface umbilical cable. The suit offers a high degree of manipulative dexterity and maneuverability. Atmospheric diving suits derive propulsive power from thrusters or manually by the operator's walking. The maximum depth of operation is 2000 ft (600 m). |
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Diver lockout submersibles
| These can be either part of a free-swimming vehicle or a tethered bell system. They carry both an operating crew and a dive team. One section of the vehicle's pressure hull is at 1-atm pressure, while the other section can be pressurized to ambient pressure to permit diver egress. Power may be derived from batteries, advanced air-independent energy systems (such as fuel cells), or a surface-connected umbilical cable. Diver-breathing gases and heating may be carried aboard or supplied through an umbilical cable. A maximum operating depth (for diver lockout) is about 820 ft (250 m). Only a few diver lockout vehicles still exist and they are rarely used for commercial work. Navies use free-swimming ones for special warfare missions. |
| The more common way of delivering commercial divers to work sites is to use a cable-lowered diving bell called a personnel transfer capsule (PTC). The divers are delivered and recovered from the dive site in a dry bell pressurized to equal the water pressure at the dive depth. A hatch in the bottom provides a means for the divers to leave and reenter the bell. On returning to the surface, the bell is mated to a deck decompression chamber (DDC) on aboard the support vessel, where the divers can decompress over periods ranging from hours to days. |
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Wet submersibles
| There are two types of wet submersible vehicles: simple diver propulsion units in which a diver holds onto and steers through the water, and swimmer delivery vehicles (SDVs) in which the diver either rides inside (Fig. 5) or sits astride. In all cases, the personnel are exposed to full ambient pressure and water temperature. These vehicles are battery-powered and designed for shallow depths, not much more than 100 ft (30 m). The breathing air is carried in on-board tanks or on the diver's back. A few swimmer delivery vehicles are designed so that the interior of the cabin does not completely flood. The crew sits in a trapped air bubble, keeping the upper halves of their bodies in pressurized air. Facemasks or regulators are not necessary while passengers remain in the vehicle. While most of these vehicles have been developed for recreation, navy special warfare personnel also use similar vehicles. |
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Remotely operated vehicles
| The first ROVs were developed in the late 1950s for naval use. By the mid-1970s, they were being widely adapted for the civil sector. In the offshore oil and gas industry, the ROV has substantially replaced both crewed submersibles and divers. |
| The rapid acceptance of these submersibles is due to their relatively low cost and the fact that they do not put human life at risk when undertaking hazardous missions. However, their most important attribute is that they are less complex. By virtue of their surface-connecting umbilical cable, they can operate almost indefinitely since there is no human inside requiring life support and no batteries to be recharged. There are four types of ROV: tethered free-swimming, towed, bottom-reliant, and structurally reliant. |
Tethered free-swimming vehicles
| These are the dominant remotely operated vehicles, and nearly 5500 have been constructed since the early 1970s. This type of ROV can be divided into two use categories: inspection vehicles (essentially swimming cameras) and work vehicles (equipped with a variety of tools and sampling devices). Costs of ROVs range from about $15,000 to several million dollars. See also: Underwater photography |
| The vehicle itself is only part of an operating system, consisting of a control/display console, a power supply, a cable winch with a cable/vehicle handling apparatus, an umbilical cable (which transmits power and control commands down to the vehicle and data and television signals back to the surface), and the vehicle handling cage or “garage” (which is optional). The ROV is always equipped with a television camera, lights, and thrusters that provide three-dimensional maneuverability. In addition, there can be depth sensors, a wide array of manipulative and acoustic devices, and special instrumentation to perform a variety of work tasks. For complex or deep-diving operations, the submersible is often equipped with an acoustic tracking system and a high-resolution sonar. This permits the surface support vessel to maintain close control of the vehicle relative to other targets on the sea floor. These vehicles can range from the size of a personal computer to that of a compact automobile. Larger ROVs are configured as basic work platforms that can use a wide variety of optional equipment according to the mission. See also: Sonar; Underwater sound; Underwater television |
| In the late 1980s, a few remotely operated vehicles with depth capabilities to 20,000 ft (6000 m) were put into service for deep ocean inspection and object recovery missions. In March 1995, the $50 million Japanese ROV Kaiko dove to 35,798 ft (about 11,000 m) into the Challenger Deep area off the Marianas Islands, equaling the 1960 record of the U.S. Navy's crewed Bathyscaph Trieste. Subsequently Kaiko returned to this site twice, demonstrating there are no depth limits to ROV capabilities. Kaiko was lost on a 6000 m dive in 2004; however, the Japanese government plans to replace it (Fig 6). |
Fig. 6 Japan's 36,000-ft (11,000-m) Kaiko, a large working ROV. (Jamstec & Mitsui Engineering and Shipbuilding)
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| The vast majority of these vehicles have been operated at depths of less than 2000 ft (600 m). However, offshore oil and gas is being produced at depths greater than 3000 ft (1000 m), well beyond diver depths. Exploratory drilling occurs at 10,000 ft (3000 m) depth and it will not be long before production begins at these depths. Here, remotely operated vehicles are not an option but a necessity and several have been developed for these applications. Long-penetration vehicles are being developed to inspect the insides of several-mile-long aqueducts, ocean outfalls, and other large pipelines. For example, in 1998, a special ROV, Phoenix, made a record-setting 6-mi-long, (10,000-m) tunnel inspection in Finland. |
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Towed vehicles
| Often called “sleds,” these are usually equipped with instruments and imaging systems for long-range surveying, search, and reconnaissance (Fig. 7). As they are towed by a surface ship, their depth is controlled by adjusting the length of tow cable. Some sleds have fins to stabilize their underwater flight. There are two varieties within this class of vehicle. One type is towed above the bottom and is instrumented for scientific research or broad-area reconnaissance. The maximum depth of this type of vehicle is 20,000 ft (6000 m), though there are only a few in the world that can operate this deep. The second type is designed to be towed while in contact with the bottom to lay and bury pipelines or cables. These are basically specialized sea-floor plows. |
Fig. 7 Components of a towed vehicle. (Marine Physical Laboratory, Scripps Institute of Oceanography)
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Bottom-reliant vehicles
| These are generally large, massive vehicles designed for a single-purpose work such as pipeline and cable burial, pipeline inspection, bottom excavation, and trench backfilling. They are controlled by an operator team on board a dedicated support ship, and maneuver on the bottom using wheels, caterpillar-like tracks, or Archimedes screws (Fig. 8). |
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Structurally reliant vehicles
| These vehicles obtain power and control from the surface, but are designed to operate in contact with a fixed structure such as an oil platform. They can run on wheels or be propelled by push-pull rams as they crawl along a pipeline or other structure (Fig. 9). These vehicles are purpose-designed and conduct such tasks as ship hull and structure cleaning, inspection and maintenance of subsea production systems, and in-water repair tasks. |
Fig. 9 Structurally reliant vehicle used for servicing seafloor oil well structures. (Kvaener Brug A/S)
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Autonomous underwater vehicles
| These are crewless and untethered submersibles which operate independent of direct human control. Practically, AUVs are mobile instrumentation platforms with propulsion, powered by on-board batteries or fuel cells. A preprogrammed, on-board computer controls their operations, although a few experimental vehicles have been controlled by acoustic commands from the surface. The data they collect is stored and often processed on-board and, after surfacing, transmitted to other stations via satellite or radio link for further processing. Autonomous underwater vehicles' depth capability is from a few hundred feet to over 20,000 ft (6,000 m). |
| First developed by the military in the early 1970s, numerous operational AUVs have entered the civil sector in recent years. Military applications include such tasks as minefield location, mapping, and neutralization; minefield installation; submarine decoys; military oceanography; and covert intelligence collection. Several navies now have operational AUV programs which actively use these vehicles in fleet operations. |
| Civilian tasks include site monitoring, basic oceanographic data gathering, under-ice mapping, offshore structure and pipeline inspection, and bottom mapping. Autonomous submersibles are particularly useful where human presence is not required and for long-duration operations. |
| Autonomous underwater vehicles span a wide range of sizes and capabilities, related to their intended missions. Large, transport-class platforms, about 33 ft (10 m) in length and 11 tons (10 metric tons), have been designed for missions requiring long endurance, high speed, large payloads, or high-power sensors. Smaller, network-class platforms, about 3.3 ft (1 m) in length and weighing 220 lb (100 kg), address missions requiring portability, multiple platforms, adaptive spatial sampling, and sustained presence in a specific region. Historically, most vehicles have been propeller-driven, but several new, variable-buoyancy, underwater gliders are emerging in the network class. |
| Over 100 autonomous underwater vehicles have been designed and built worldwide since 1963 by government laboratories, industry, and academia. Through the mid-1990s, most AUVs in all classes were research prototypes. By 2000, an increasing number of operational military and commercial vehicles were available, particularly in the network class. Developments in microprocessors, memory, batteries, and fuel cells are leading to higher performance in smaller platforms. Likewise, fiber optics and micro-electro-mechanical systems are spawning a new generation of compact, high-precision, low-power sensors ideally suited for payloads on autonomous underwater vehicles. The Global Positioning System (GPS) and emerging global communication services are enabling timely access to data and real-time control. See also: Micro-electro-mechanical systems (MEMS); Satellite navigation systems |
| A major obstacle to more extensive use of AUVs is the limit on the amount of on-board power they can carry, thus limiting mission duration. Most submersibles of this type are powered by batteries. True long-duration missions will require an alternative to battery systems. Research is ongoing to find other power systems, such as fuel cells and solar cells which can be mounted on the vehicle. See also: Battery; Solar cell |
Transport class
| In the transport class, the Mobile Undersea Systems Test Laboratory is the world's largest autonomous underwater vehicle: 33 ft (10 m) long, 4 ft (1.2 m) in diameter, weighing 10 tons (9.2 metric tons), rated to 1970 ft (600 m) depth, with an 87-mi (140-km) range and 1.1-ton (1-metric-ton) payload capacity. Other transport-class vehicles rated to full ocean depth include the French Epaulard, the Russian MT-88, the Chinese CR-01, and the Theseus, developed for the Canadian Department of National Defense. Theseus is rated to 3280 ft (1000 m) depth with an operating range of 466 mi (750 km) and an endurance of 100 h. In 1996, Theseus completed two missions under the Arctic icecap of 218 mi (350 km) and 50 h in duration. |
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Intermediate class
| Intermediate between transport class and network class are vehicles such as the Marine Utility Vehicle System (MARIUS). At 14.8 ft (4.5 m) long, 2 × 3.6 ft (0.6 × 1.1 m) in rectangular cross section, and rated to 1970 ft (600 m) depth, MARIUS has an operating range of 31 mi (50 km) and is used for seabed inspections and environmental surveys in coastal waters. The Norwegian-built Hugin 3000 AUVs have been quite successful commercially in doing seafloor surveys to depths as great as 9000 ft (3000 m) and for missions as long as 48 h. |
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Network class
| Typical high-performance, propeller-driven vehicles in the network class include the Autonomous Benthic Explorer (ABE) and the Remote Environmental Monitoring Units (REMUS). Developed by the Woods Hole Oceanographic Institution, ABE is 992 lb (450 kg) in air, rated to 3.7 mi (6000 m) depth, and has an operating range of 62 mi (100 km). In 1997, ABE mapped magnetic anomalies associated with deep-ocean spreading zones in the North Pacific. REMUS, a highly portable, shallow-water vehicle is 5 ft (1.5 m) long, 8 in. (20 cm) in diameter, 88 lb (40 kg) weight in air, with up to a 50-mi (80-km) range (Fig. 10). REMUS has mapped water properties and performed mine reconnaissance to the edge of the surf zone. The U.S. Navy has used one of these submersibles for mine countermeasure work in the Arabian Gulf. |
Fig. 10 REMUS is rated for continental shelf depths (355 ft; 200 m) and is compact and lightweight (40 kg; 88 lb). It is depicted with its laptop computer for downloading missions and uploading data, and one of the acoustic transponders used for navigation. (Woods Hole Oceanographic Institution)
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| Network-class, buoyancy-driven vehicles are small, near-neutrally-buoyant platforms that move vertically and horizontally through the water because of small changes in buoyancy. One such vehicle, the Virtual Mooring Glider (VIRMOG), is fitted with battery-operated buoyancy controllers, and can operate with an estimated 40-day, 497-mi (800-km) range independent of temperature gradient. VIRMOG is designed for both deep- and shallow-ocean sampling, and uses changes in buoyancy for propulsion (underwater glider). Batteries are used as the energy source for the variable-buoyancy engine. One mission envisioned for VIRMOG is as a holding station at a fixed location, thus virtually emulating a mooring. |
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Hybrid vehicles
| Hybrid vehicles are those that combine crewed vehicles, remotely operated vehicles, and divers. For example, the hybrid DUPLUS II can operate either as a tethered free-swimming ROV or as a 1-atm tethered crewed vehicle. This evolved to provide capability for remotely conducting those tasks for which human skills are not needed, and then to put the human at the place where those skills are required. Other hybrid examples include ROVs that can be controlled remotely from the surface or at the work site by a diver performing maintenance and repair tasks, bottom-crawling ROVs controlled by a diver to anchor a pipeline or cut a trench, and small “scout” ROVs that can “fly off” from a larger ROV. The Woods Hole Oceanographic Institution's Argo-Jason is an example of the fly-off system. It combines a towed vehicle (Argo) with a tethered free-swimming vehicle (Jason). Argo conducts large-area search or reconnaissance, while Jason (carried within and deployed from Argo) conducts detailed inspection and manipulation of objects of interest encountered during the towing phase. |
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Applications
| Almost every conceivable underwater work task from military missions to recreational activities and from offshore oil and gas to environmental conservation has used submersibles. While there will always be a need for divers, as working depths increase the need for submersibles will continue to increase. The question of whether crewed submersibles will be replaced by ROVs and ROVs by AUVs is not valid. It is best to consider these types of vehicles, and all their variants, as a “family” of tools. The in situ worker chooses the best ones for a given job. A sample of work areas are listed below. |
Offshore oil and gas activities
| At one time, there was a clear distinction between the tasks that remotely operated vehicles performed in support of offshore oil and gas operations and those performed by divers and crewed submersibles. Over time, the capabilities of ROVs have increased to the point that almost every task once done by divers and crewed submersibles can now be done with ROVs, often better, and always at lower cost. As a result, crewed submersibles are rarely used in this business. |
Observation, and video or photographic documentation
| This is of the strongest areas of ROV uses, although in a few cases some crewed vehicles are still used. The latter tend to be the 1-atm tethered and atmospheric-diving-suit (ADS) type submersibles. In shallow depths (<115 ft or 35 m) the diver is preferred. Observational tasks include determining the geometry and position of pipelines and cables following installation, determining the condition of a pipeline's concrete coating after installation, obtaining accurate positions of pipeline tie-in locations, leak detection monitoring, inspecting a wellhead for structural integrity, investigating accidents, and accumulating information needed to develop salvage or retrieval plans. Also included are bottom surveys such as pipeline and cable route selection, verification surveys, hardware site installation surveys, and debris identification and location mapping. |
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Structural nondestructive testing
| This technique is used to locate and identify bent, broken, or missing structural members, identify and map debris location on structures, assess and remove marine growth, locate suspended pipeline and cable sections, perform structural-member thickness measurements, detect and measure cracks and flaws, and measure the effectiveness of the structural cathodic protection system. |
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Support of diver operations
| Remotely operated vehicles can provide diver support and monitoring, including initial diving-gear checkout for leaks, continuous diver monitoring of job performance, safety, assistance in locating the diver's position, topside understanding of diving conditions, evaluation of the dive site in terms of diver safety prior to dive, provision of an additional and mobile light source, monitoring and inspection of the diver's work, and television or photographic documentation of the diver's work. |
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Object search, location, and retrieval assistance
| Underwater vehicles are used to locate lost or abandoned objects, to determine the object's position relative to the surface salvage or retrieval vessel, and to provide assistance in attaching lift lines or cables to objects for retrieval. The majority of underwater vehicles cannot lift items weighing more than 110–220 lb (50–100 kg). Often separate lift systems (underwater elevators) are employed to work together with the submersible to bring heavy loads to the surface. |
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Oversight of underwater activities
| Underwater vehicle are used to monitor underwater construction from surface platforms (such as ships, barges, and docks). These tasks include grouting operations, piling installation, alignment and orientation measurements during structural installation, observation of pipeline pull-in procedures, pipeline weighting and backfilling operations, and touchdown operations (for example, pipeline installations or spudding-in of drills). |
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Drilling support assistance
| This is supplied by locating and retrieving objects, debris, and equipment; removing sediment to permit observation of components; connecting and disconnecting shackles and hydraulic/electric lines; collecting grout and bottom samples; operating valves; observing the drillstring operation and blowout preventer installation; and placing and recovering acoustic marker beacons. |
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Support of routine deepwater production operations
| With hydrocarbon production occurring in increasingly deep waters that are well beyond diver depths, the routine management, inspection, and maintenance of seafloor structures with their associated pipelines is being done with ROVs. As the AUV technologies and techniques mature, eventually they will be used for tasks where a tethered vehicle is not feasible. In all cases, the sea-floor structures will be configured to be vehicle friendly for the mechanical arms (manipulators) and electronic eyes on the submersibles. |
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Marine leisure
| This sector is the single largest user of crewed submersibles. Built in the early 1960s, the Auguste Piccard was the first tourist submarine. This 64-passenger submersible was used at the 1964 Swiss National Fair in Geneva. Crewed by pilot, copilot, and stewardess, it carried over 34,000 paying passengers during the 14-month-long fair. |
| In 1985, a Canadian company, Atlantis Submarines, built the 28-passenger Atlantis I, which was placed into service at Grand Cayman Island. This began a business sector that has employed some 60 crewed submersibles since that time. While a few of the early tourist submarines were conversions of existing DSVs, 51 were built for the business sector. The largest is the 66-passenger Atlantis XIV operating off Waikiki Beach, Hawaii. Thirteen Atlantis submarines are now in operation at Grand Cayman, Barbados; St. Thomas, U.S. Virgin Islands; Aruba; Cozumel; Hawaii; and Guam (Fig. 11). Tourist submersibles have operated in 34 countries throughout the world. By 2005, they had carried nearly 12 million passengers with no serious incidents. A typical dive lasts about 1 h and goes to depths of 100–150 ft (30–46 m). There are also two small converted commercial-type submersibles at Grand Cayman that take two passengers to depths of 1000 ft (300 m). |
| The large passenger-carrying submersible business is a mature market sector. The best sites are occupied and few new submarines will be added to the fleet in the future. There is a new development direction, the resort-sized submersible for locations that cannot support a 40–50-passenger vehicle. These DSVs have a 2–20-passenger capacity and are better suited for destination resorts and smaller marine leisure locations. In 2005, an American company launched the Alicia, a 1000-ft (300-m) tourist submersible that can carry six passengers. |
| In addition to passenger-carrying tourist submarines, there are a number of personal or recreational submersible designs now being offered to the leisure market. Most of these are wet submersibles, although in 2005 two 1-atm DSVs were delivered to private owners. |
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Military
| The most important applications are intelligence gathering, search, identification, location, retrieval, and neutralization of ordnances. These include explosive ordnance (mines, torpedoes, and bombs), downed aircraft, sunken vessels, and other objects of high national interest. Other military applications include hardware site and cable route survey, submarine rescue, wreck marking and destruction, topographic surveying, radiation measurements, water sampling, and water turbulence measurements and tests. |
| For several years, special warfare organizations, such as the U.S. Navy SEALS, have used small submersibles as swimmer delivery vehicles. In general, they are carried on submarines and the submersibles are launched and recovered while the submarine is submerged. In the larger navies, “wet” ambient-pressure vehicles are being replaced by 1-atm dry submersibles. However, many of the smaller navies in the world will continue to use the wet submersibles for covert operations. |
| Up through the 1970s, military research and development was the primary force behind the development of all types of submersibles. Today, almost all underwater submersible development is done in industry and academic research facilities. The military either contracts with them for services or buys this equipment from the private sector. |
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Scientific research
| The crewed vehicle, particularly the 1-atm untethered variety, continues to be the workhorse of the scientific community. Twenty-four are in service worldwide for support of marine research. In this role, the submersible has become a very sophisticated platform from which the scientist can directly observe and measure a variety of environmental aspects, which are best understood by direct visual observation. The best-known is the Navy-owned Alvin, which has been operated by the Woods Hole Oceanographic Institution (WHOI) since 1964. Diving as deep as 13,000 ft (4000 m), Alvin has made many significant discoveries in the deep ocean. Since the early 1980s, a family of 20,000-ft (6000-m) DSVs have been used for research work. Examples of this class are the two Russian Mir submersibles in operation since 1987 (Fig. 12). |
Fig. 12 One of the two Russian Mir 20,000-ft (6,000-m) manned submersibles. (P.P. Shirshov Institute of Oceanology)
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| In recent years, several scientific institutions have started to use remotely operated vehicles for research platforms. They offer an affordable submersible platform with excellent flexibility for a wide range of mission configurations. The rapid progress in development of microcomputers has made it possible to put much more capability into these small vehicles. See also: Microprocessor |
| Towed vehicles have been used for research tasks since the 1960s. They are used to conduct deep-water geophysical and geological surveying and reconnaissance, midwater biological and water sampling, and collection of sea-floor sediments. |
| Some scientific organizations have combined the use of remotely operated and crewed vehicles to economize operations and at-sea time. For example, studies of hydrothermal vents by the crewed submersible Alvin were preceded by observing many square miles of sea floor with the towed vehicle Angus (which actually discovered the vents). Alvin, with its human observers, was subsequently deployed to conduct closeup observations and sampling, its primary role. Later, a small remotely operated vehicle, Jason Jr., was used to swim off from Alvin to investigate places on the wreck that were too narrow or hazardous for the crewed vehicle to enter. This practice of using a towed vehicle to perform a relatively high-speed, large-area reconnaissance and a crewed vehicle (sometimes with an on-board ROV) for final significant observations saves many days, perhaps months, of effort, since the crewed submersible is not an effective high-speed search and survey platform. See also: Hydrothermal vent |
| The AUV has become a powerful new platform for oceanographic research where high-quality measurements are required but human presence is not. Eventually it should be possible for AUVs to make unattended transects of oceans, with the vehicle moving between a set depth and the surface while taking a variety of oceanographic measurements. Navigation updating and data transfer can be done by a radio link between the AUV and a satellite in space. As noted earlier, the major technical problem is getting enough power on board to support long-duration missions. In the 1990s, a Russian group proposed an AUV equipped with solar cells that can recharge batteries when the vehicle is on the surface transmitting data to a satellite. In 2003, a U.S. company put this type of AUV on the market. |
| In addition to operational AUVs, the future will bring crewed long-duration systems. Only one example exists at present, the U.S. Navy's NR-1. The small nuclear-powered NR-1 can operate with mission times of up to a month. |
| U.S. Navy nuclear submarines have been used to do scientific research under the ice in the Arctic, the least-known ocean. However, the last of the fully ice-capable submarines was retired in 2000. Military submarines are not ideal for the long-duration scientific missions, while NR-1 has relatively short endurance. The optimum platform would be a built-for-the-purpose nuclear submarine. In the early 1990s, a Canadian company and their Soviet Union partner proposed the development of Ocean Shuttle, a long-duration, multimission, crewed submarine analogous to NASA's space shuttle system. It was not built due to the end of the Cold War and a change in Canada's government. Such a submarine platform will be expensive to build and operate, but it offers the only means to do certain kinds of critical research in the world ocean. This type of underwater platform will eventually be developed because there are ocean work tasks that can only be done in this way. |
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Other uses
| As the work capabilities of underwater vehicles have been proved, additional new opportunities have opened up. This is especially true in the uses of tethered, free-swimming ROVs. They now have a wide variety of civil uses such as fisheries resources management; inspection and maintenance of ships; law enforcement and public safety; marine pollution detection, remediation, and monitoring; treasure hunting; and underwater archeology. Many of these uses take advantage of vigorous price competition at the low end of the inspection vehicle market, where an ROV can be obtained for about $15,000. The evolution of the AUV will also follow a similar path to provide affordable systems to a wide community. While these economies are being realized, the top-end submersibles will increase in complexity, capability, and price. See also: Submarine |
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Bibliography
- American Bureau of Shipping, Rules for Building and Classing Underwater Vehicles, Systems and Hyperbaric Facilities, ABS, 2002
- R. D. Ballard, The Eternal Darkness: A Personal History of Deep-Sea Exploration, Princeton University Press, 2000
- W. J. Broad, The Universe Below, Simon & Schuster, New York, 1997
- W. Forman, The History of American Deep Submersible Operations, Best Publishing, 1999
- G. Griffiths (ed.), Technology and Applications of Autonomous Underwater Vehicles, CRC Press, 2002
- Jane's Underwater Technology 2005-06, Janes Publishing, New York, 2005
- Marine Board, National Research Council, Underwater Vehicles and the National Needs, National Academy Press, Washington, DC, 1996
- G. Roberts et al. (eds.), Guidance and Control of Underwater Vehicles 2003, Elsevier, 2003
- Underwater News & Technology, Remote Operated Vehicles of the World 1998/99 Edition, Technology Systems Corp., Stuart, FL, 1999
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Additional Readings
- M. D. Ageev, The use of autonomous unmanned vehicles for deep-water search operations, Subnotes, September-October 1990
- B. Grandvaux and J. Michel, Epaulard: An acoustically remote controlled vehicle for deep ocean survey, Proc. Mar. Technol., 79:357–359, 1979
- H. Li, New robotic vessel extends deep-ocean exploration, Science, 278:1705, 1997
- D. R. Yoerger, A. M. Bradley, and B. B. Walden, The Autonomous Benthic Explorer (ABE): An AUV optimized for deep seafloor studies, Proceedings of the 7th International Symposium on Unmanned Untethered Submersible Technology, University of New Hampshire, Doc. 91-9-01, 1991.
- Autonomous underwater vehicles: A collection of groups and projects
- WHOI DSL Subsea vehicles
- AUV Resources
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How to cite this article
| | Don Walsh, "Underwater vehicles", in AccessScience@McGraw-Hill, http://www.accessscience.com, DOI 10.1036/1097-8542.720550 |
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