This section provides some history and general background information on ROVs as well as the current state of ROVs.
Background and History
The first step in understanding any technology is to understand why it exists. In the case of ROV technology the answer is quite simple. There is no other practical, safe and economically feasible way to perform deep underwater intervention.
History tells us that humans have been doing everything from gathering food to salvaging cannons and performing other tasks underwater for several centuries. The first attempts to improve diving efficiencies were recorded in the mid sixteenth century, when the first diving "helmet" was used. A drawing of this device provides evidence that is was some sort of a greased leather bag with an extension tube to the surface. From that early technology to the record 2,250-foot simulated dive made at Duke University in 1981, we witnessed an incredible evolution in humans' ability to work underwater. Open water dives have been made to nearly 2,000 feet and commercial dives have been done to 1,750 feet, but these instances are very rare, involve high risk, and are not economically feasible.
Human occupied vehicles (HOV), formally called manned submersibles, appeared to be the solution to conquering the deep for a short time in history. The problem was they suffered many of the same disadvantages as hyperbaric diving. Between the mid nineteen-sixties and mid-nineteen-seventies it looked like HOVs would allow deeper work for longer periods of time. The problem was that HOVs required substantial dedicated support vessels and still put humans at risk underwater. They also were slow to launch and recover and had limited bottom time, rendering them economically ineffective. The introduction of commercial ROVs in the mid-seventies has relegated HOVs to limited use in science and the tourist industry.
Exactly who to credit with developing the first ROV will probably remain clouded. However, there are two who deserve credit. The PUV (Programmed Underwater Vehicle) was a torpedo developed by Luppis-Whitehead Automobile in Austria in 1864, but, the first tethered ROV, named POODLE, was developed by Dimitri Rebikoff in 1953.
The United States Navy is credited with advancing the technology to an operational state in its quest to develop robots to recover underwater ordnance lost during at-sea tests. ROVs gained in fame when US Navy CURV (Cable Controlled Underwater Recovery Vehicle) systems recovered an atomic bomb lost off Palomares, Spain in an aircraft accident in 1966, and then saved the pilots of the sunken submersible Pisces off Cork, Ireland in 1973, with only minutes of air remaining in the submersible.
The next step in advancing the technology was performed by commercial firms that saw the future in ROV support of offshore oil operations. The transition from military use to the commercial world was rather rapid. Manufacturing companies like International Submarine Engineering in British Columbia, Perry Oceanographic in Riviera Beach, Florida, and Hydro Products and Ametek Strata in San Diego, California were quick to begin commercial activity based on work done for the military.
Commercial diving companies like Seaway (a small company in Norway), Martech (a small independent Gulf of Mexico company), and Taylor Diving and Salvage (a Halliburton subsidiary) were anxious to extend their capabilities with this new technology. It often became a case of "beware of what you wish for." Factory acceptance tests and sea trials, scheduled for just a few days, often became ordeals lasting weeks. Once at the work site, the operators were happy if they got the vehicle back, and were really happy if they got more than 4 hours of productive time per 24-hour day. Some of the people, like Drew Michel, Wade Abadie, Kevin Peterson and Charles Royce, who suffered through those early long days and nights are still around.
From that very "humbling" beginning, the technology and industry of today has evolved. The following paragraphs attempt to provide a synopsis of the ROV world now.
What is an "ROV"
Two publications, the MTS ROV Committee's "Operational Guidelines for ROVs" (1984) and the National Research Council Committee's "Undersea Vehicles and National Needs" (1996), describe a Remotely Operated Vehicle (ROV) as an underwater robot that allows the vehicle's operator to remain in a comfortable environment while the ROV performs the work underwater. An umbilical, or tether, carries power and command and control signals to the vehicle and the status and sensory data back to the operators topside. In larger systems, a subsea garage and tether management system (TMS) are often included.
ROVs can vary in size from small vehicles fitted with one TV camera, like the three shown below that are used for simple observation, up to complex work systems that can have several dexterous manipulators, video cameras, mechanical tools and other equipment. They are generally free flying, but some are bottom-founded on tracks. Towed bodies, such as those used to deploy side scan sonar, are not considered ROVs. Lifting and rock dumping devices employing thrusters for lateral motion only are also not normally included in listings of ROV systems.
Small (Electric) Vehicles
Many small or "flying eyeball" ROVs, some as small as a breadbox, are in use today. The exact number of them has become simply too large to track. The best guess is that more than one thousand of these vehicles are at work worldwide. This small vehicle class includes the majority of "low-cost" vehicles, most of which are typically all electric and operate above 984 feet (300 meters) water depth. These vehicles are used primarily for inspection and observation tasks. There has been a recent surge in the development of small vehicles, due primarily to the improvement in technology for electrically powered systems. These improvements have resulted in an increase of capability, performance and depth not previously achieved.
Costs for these small ROVs range from around $10,000 to $100,000. The low-end products have been classified for Marine Recreational Use, while the more expensive systems have been used for inland water inspection projects and coastal offshore inspection and observation tasks. Some of the earlier systems were simply video camera housings with thrusters. Today's low-cost ROVs are used widely for many tasks including science, search and rescue, dam, waterway and port inspection, training, shipping and nuclear inspection.
High Capability Electric ROVs
Although ROVs like the infamous Perry RECON vehicle have been around for some time, they are limited in both depth and performance. A new class of electric ROVs, represented by the Schilling Quest vehicle shown below, was born recently which features the latest in technology from Brushless DC motors (thrusters) to PC-based control systems and fiber optic telemetry systems. Electrically operated vehicles can be made to go 20,000 feet (6,096 meters) with much less power required to operate them at depth. The ability to do heavy work is still not possible with the electric ROVs, which are primarily limited by the required electro-hydraulic design of modern manipulator and work systems, but they can still perform many tasks at a much lower cost.
Electric vehicles have gained popularity with the military and science markets due primarily to their quiet operation. In addition, the work requirements for military and science are, in most cases, not as complex when compared to ROVs used for oil and gas operations.
Work Class Vehicles
This class of ROV refers to electro-hydraulic vehicles ranging from 50-100 horsepower typically, which can only carry moderate payloads and have limited through-frame lift capability. These ROVs range in weight from 2,205-4,410 lbs (1,000-2,200 kg) with typical payload capacities in the 220-600 lb (100-272 kg) range. Most carry a seven function rate manipulator and a five function grabber. Some have the capability of through-frame lift of over 1,000 lbs (454 kg). These vehicles comprise the most widely used ROV class, which evolved from the early "eye ball" systems that were used to observe divers working or to perform routine inspections. Typical tasks for this class are drilling support (where most are deployed), light construction support, pipeline inspection and general "call out" work.
Heavy Work Class Vehicles
This represents the class of ROVs being used for current deepwater operations to 10,000 feet (3,000 meters) ranging from 100-250 horsepower and having through-frame lift capabilities to 11,025 lbs (5,000 kg).
With new requirements to perform subsea tie-in operations on deepwater installations and to carry very large diverless intervention systems, this class of ROV is becoming increasingly large, powerful and capable of carrying and lifting large loads- thus the term "heavy work class vehicle" has been adopted by the industry. These vehicles can weight more than ten thousand pounds and resemble a minivan in size. Three-thousand meter depth capable systems are now commonplace, with at least one system capable of six thousand meters. A cable and flow line burial system powered by four electro hydraulic units totaling one thousand horsepower is in use today, and at least one ROV that can lift and maneuver sixteen hundred pounds has been built. Cameras, lights, sonars and other sensors necessary to operate at great depths are readily available. Manipulators capable of lifting hundreds of pounds are commonly installed on these vehicles.
The latest estimate (March 2004) is that approximately 435 work- and heavy work-class ROV systems are active in the world today. The best guess is that this represents over $1.5 billion in capital assets. Seven major commercial operators own the majority of these systems with a total of approximately 405 listed in their respective inventories. Smaller companies, academia, and other non-commercial organizations operate another 30 systems. This total count does not include mine-hunting and other specialized military equipment.
Work Class ROV systems operating worldwide
Oceaneering International, Inc. 152
Subsea 7 (Halliburton/Subsea) 78
Stolt (Stolt/Comex/Seaway) 35
Sonsub (Saipem) 59
Fugro (ex Racal/Thales) 36
Canyon (Cal Dive) 23
Technip-Coflexip 22
Others- Approximate number of specialty systems, plus systems operated by smaller companies.
(Source: Drew Michel interviewing contractors March 2004) 30
Total Systems
435
The fortunes of the ROV industry track the level of activity in the offshore oil and gas industry. Companies that produce hydrocarbon reserves from the depths of our oceans, to supply us with the heat, light and mobility we rely on for our every day existence, employ the vast majority of the world's work class ROV systems. The second most significant market for ROV technology is in support of installing and maintaining undersea cable systems. The split of use in support of hydrocarbon production and undersea cables is hard to define because of the dual use of many systems, but a fairly accurate estimate of use of the approximately 400 commercial systems deployed worldwide is about 85 percent hydrocarbon production and 15 percent undersea cable support.
The next step in the underwater intervention evolution is to Autonomous Underwater Vehicles (AUV). A few AUVs are being used by the military, for science, and in the commercial world for survey work. AUVs that actually perform heavy physical tasks are in development. The primary limitation is the power the AUV can carry. Rather than making quantum leaps to AUV technology, ROV systems will evolve to hybrid systems. Control and feedback will continue to be provided through thin fiber umbilicals, with power carried on board and charged by stations on the seafloor. They will be deployed to maintain subsea production systems and the associated pipeline manifolds. Undersea observatories will use a similar approach. Picture an AUV that swims from docking station to docking station to dump data and recharge. For more on this subject look for the MTS AUV Committee website coming soon.
For more details from a CD entitled "Operational Effectiveness of Unmanned Underwater Systems" click here and the CD is available for purchase here.
http://www.rov.org/info.cfm
