Swimming Socket Wrenches
The Underwater History of Remotely Operated Vehicles
Much of today’s offshore oil and natural gas industry relies on remotely operated vehicles (ROVs) that can trace their roots back to Howard Hughes, Jr.
In the late 1950s, Hughes Aircraft Co. developed its Manipulator Operated Robot – MOBOT – for the Atomic Energy Commission. Working on land, the robot performed tasks in environments too radioactive for humans.
Weighing 4,500 pounds with hydraulically powered steel claws and television eyes, MOBOT was linked by a 200-foot cable to the operator, who used pistol grips and levers to control it. In 1960, Popular Science magazine declared, “Marvelous MOBOT Will Do Work Too Hot For Man.”
The offshore petroleum industry recognized the robot’s underwater potential.
As the search for oil reached deeper into the ocean’s depths, traditional hard hat diving technology advanced to keep up.
The advent of saturation diving and helium/oxygen mixtures extended depths and diving times and reduced the dangers of decompression sickness – “the bends,” but there were limits to what divers could accomplish in the increasingly hazardous depths. See “Deep Sea Roughnecks.”
Shell Oil Company took the lead in transforming Hughes’ landlocked MOBOT into what would one day become known as an ROV.
Beginning in 1960, a series of evolving patents described, “a remotely controlled manipulator device for carrying out operations underwater at an assembly position at the top of a well.”
Patents by Howard Shatto Jr. – named to the Offshore Energy Center’s Industry Pioneers Hall of Fame in 2000 - and others made Shell Oil Company the early leader in offshore development.
Shatto explained how an underwater device patented in January 1965 particularly related to the offshore petroleum industry:
“A recent development at offshore locations is the installation of large amount of underwater equipment used in producing oil fields and gas fields situated many miles from shore,” he noted. “Many of the wells are being drilled in water up to 600 feet deep, a depth greater than divers can safely work.”
The inventor added that a primary objective of his design is to provide a “manipulator device” with articulated arms that can secure itself to a wellhead on the ocean floor. “Each of the arms is provided at its outer end with a suitable suction means in the form of a suction cup.”
According to the Offshore Energy Center, Shatto led in the “design of the first subsea wellheads for drilling and production using an ROV” and became “a world-respected innovator in the areas of dynamic positioning and remotely-operated vehicles (ROV).
He conceived the world’s first automatic control for dynamic positioning on Shell’s Eureka core drillship in 1960. It controlled surge, sway and yaw independently and resolved thruster commands, a procedure followed on the more than 1,300 dynamic positioning systems built since then.
Shatto will also lead in the development of “drilling without anchors” – the Sedco-445, considered ”the world’s first dynamic positioning oil exploration drillship.”
Swimming Socket Wrench
Hughes Aircraft Company built the first marine MOBOT for Shell Oil, using sonar and television cameras for navigation, propellers for propulsion, and an umbilical cable for control.
With a mechanical arm, it could turn bolts, operate valves and attach control hoses and guide lines.
“It was basically a swimming socket wrench,” said a Shell engineer, describing the 14-foot, 7,000-pound underwater robot.
Because of the necessity to pay traditional divers to rescue entangled MOBOTs, early models also became known as “a diver’s best friend.”
Nonetheless, Shell successfully used a MOBOT on a wildcat well in 250 feet of water off the coast of Santa Barbara, California, in October 1962. Over the next 10 years, MOBOTs worked on 24 offshore wells – operating to depths of 1,000 feet for extended periods.
During the Cold War, the U.S. Navy developed its own deep-sea technology for both submarine rescue and antisubmarine purposes. In 1963, the nuclear attack submarine USS Thresher sank with the loss of all hands 220 miles off the coast of Cape Cod, Mass.
The only vehicle capable of reaching a depth of 8,400 feet was the Navy’s manned bathyscaph Trieste, which found and photographed the wreckage. Unfortunately, Trieste had little capability to retrieve objects.
In January 1966 near the coast of Spain, a U.S. Air Force B-52 collided with its refueling tanker, scattering debris and four 70-kiloton hydrogen bombs over the Spanish coast. Three of the nuclear bombs were recovered on land, but the fourth was lost in the Mediterranean Sea.
With a combination of divers and the Woods Hole Oceanographic Institution’s manned submersible, Alvin, the missing atomic bomb was located at a depth of 2,850 feet. To retrieve it, the Navy employed its new CURV I (Cable-Controlled Underwater Recovery Vehicle), which snagged the bomb and pulled it to the surface.
The worldwide publicity of the Palomares incident briefly elevated the visibility of marine robotics, but they largely remained submerged in military, scientific, and offshore oil applications.
Secret of the Titanic Discovery
In 1982, oceanographer and former naval intelligence officer Robert Ballard, in search of Titanic, approached the U.S .Navy as a possible source of funding.
The Navy cared little for the Titanic, but was very interested in developing Ballard’s fiber optic video system for deep sea survey and its potential to examine the debris fields of Thresher and Scorpion.
With Navy support and his highly classified mission presented to the public only as “a search for Titanic,” Ballard’s Argo surveyed and photographed both submarine wrecks, yielding invaluable data to his covert sponsors.
Completing the secret mission’s final objectives with 12 days to spare, Ballard’s team used Argo to find the wreck of Titanic on September 1, 1985, to worldwide acclaim. For 73 years Titanic had remained hidden at a depth of 12,460 feet.
A year later, Ballard brought the Woods Hole veteran deep-diving manned submersible, Alvin, to the Titanic. Then, for the first time, the public was able to see deeper into Titanic’s ghostly decks through the fiber optic eyes of Jason Jr., and later, Hercules, two increasingly sophisticated ROVs that brought the technology to prime-time television.
Offshore Petroleum Production
While such “Eyeball Class” ROVs were well suited for marine archeology, observation and inspection, the demands of deep offshore oil production demanded further development of heavy “Work Class” ROVs that could be equipped with a variety of tools.
Today, such ROVs can weigh ten thousand pounds, lift over one thousand, and operate at 10,000 foot depths. The petroleum industry is the principle user of this class of ROV. Further offshore exploration is prompting yet a new generation of marine robotics – the Autonomous Underwater Vehicle (AUV) which abandons the use of a physical cable connection to the mother ship.
Defined as “a crewless, non-tethered submersible which operates independent of direct human control,” AUVs make detailed maps of seabed topography and hazards that could impact proposed oil and natural gas offshore infrastructure.
Modern, survey class AUVs remain an emerging offshore technology – separated from Howard Hughes’ simple MOBOT by only 50 years.
Also see “Petroleum Survey finds U-166.”
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