Designing and building ROV Tiburon
Building the remotely operated vehicle (ROV) Tiburon was the institute’s major project in the 1990s. The new underwater vehicle demanded the lion’s share of the institute’s engineering brain-power for several years. The purchase of a commercial ROV for the institute’s first submersible, Ventana, was the initial step to develop in-house an exclusively scientific platform for supporting deep-ocean research. The month-in, month-out experience of operating and modifying Ventana provided invaluable technical contributions to the design of Tiburon.
When Tiburon came online in 1997, it met David Packard’s goal of creating an ROV that represented the cutting edge of ocean technology. The MBARI-designed and built vehicle was the most sophisticated all-electric ROV being used for ocean science.
In December 1997, when Tiburon made the first dive to its design depth of 4,000 meters, engineers, technicians, and crew watched depth readings on a video monitor aboard the mother ship, the R/V Western Flyer. When the underwater robot reached its dive limit in the inky depths of Monterey Canyon, about 130 miles from shore, a triumphant cheer broke out in the control room.
At the time, Mark Chaffey, a key member of the Tiburon engineering team, commented that it was “tremendously gratifying to have Tiburon show it can reach 4,000 meters and do the tasks it was designed to do”, and indicated that reaching the design depth was a measure of success. "Our job was basically to design a high-speed, networked computer system that operates at the end of a 5,000-meter long cable. The ROV is surrounded by electrically conductive seawater where pressures at its depth limit are 5,800 pounds per square inch. It's an extremely harsh environment."
The vehicle’s depth capability of 4,000 meters—almost two-and-one-half miles—was carefully chosen: It is the average depth at which the floor of the Pacific Ocean meets the continental rise of western North America. With its all-electric design, Tiburon was one of the most sophisticated underwater vehicles being used for ocean research. Its precision thrusters and other specially engineered systems allow for high performance control while keeping noise and water disturbance at a minimum—an important advantage for biologists eager to learn more about life in the deep ocean. Tiburon also has a variable buoyancy system that allows its operators to precisely manipulate the vehicle. The compact-car-sized science platform can hover inches above the seafloor to pluck a rock sample with its robotic arm, or maneuver swiftly to track animals through the water.
ROV "pilots" control Tiburon electronically via a 5,000-meter (16,250-foot) tether, its power and telecommunications lifeline to the mother ship. Likewise, video signals from the ROV’s sophisticated cameras are relayed via the cable back to the control room on the ship, where scientists manipulate the cameras and lights to capture deep-sea images. The umbilical cord weighs 3,530 kilograms (7,782 pounds) when fully paid out in water, and the enormous tension it exerts stretches it about 14 meters (46 feet) in length.
The core vehicle is equipped with a suite of built-in sensors, imaging sonar, a manipulator arm, an acoustic navigation system, and more than a dozen advanced, independently operating computers. MBARI engineers have developed modular "toolsleds"—customized instrument packages for tasks such as animal collection and ocean-bottom experiments—that attach and detach easily to and from the core frame.
With its ability to investigate Monterey Canyon’s deepest depths and record the details on videotape, Tiburon opened a new realm to MBARI scientists, who had been conducting ROV-assisted research in the submarine canyon for a decade. As Chaffey put it, "It’s very exciting to have a huge new area of the ocean now accessible. I imagine that it may become routine for us, but for now each dive to these depths has the thrill of discovery."
The R/V Western Flyer, which was delivered to Moss Landing in 1996, was built specifically to serve as a platform for Tiburon missions. Every aspect of its infrastructure—from the science control room and the computing network to the ship’s automated monitoring system—was arranged to facilitate ROV missions. Also uncommon for submersible-equipped research vessels, the new ship was built with a center well—called a “moon pool”—between its two hulls. The moon pool serves as the launching point for deploying ROVs and other instruments. A crane lifts up the ROV and, after the moon pool accordion doors open to the sea below, the crane lowers the submersible into the water, then retrieves it following a dive. Adjacent to the moon pool, a cable-handling system controls the tension of the ROV tether. As the vehicle carries out its mission, the head of the crane—through which the tether is paid out—bobs up and down to compensate for ship motion. This diminishes stress on the heavy tether and decreases its movement in the water.
One of Tiburon’s most defining characteristics is its computing system, largely a product of the ingenuity of the institute’s computer engineers. The computing hardware and software architecture rely on a half-dozen data concentrators (input/output multiplexers) and peripheral computers that collect data from many types of instruments and sensors and process them independently. The derived information is then relayed to a data manager and the main computer, which transmits it shipboard. There the data are uncompressed and distributed to various user stations. The computer architecture developed by the Tiburon team was designed such that if problems should occur in one part of the system, they would not cripple operations in the rest of the system.
Making the most of these technological advances, in 2000 MBARI engineers collaborated with Woods Hole Oceanographic Institution (WHOI) to use aspects of this technology with their new vehicle, Jason II.
Science accomplishments made possible by Tiburon and the R/V Western Flyer:
- Collecting animals for a unique exhibit at the Monterey Bay Aquarium that made the deep sea—Earth’s largest habitat—accessible to the general public.
- In situ studies of the effects of sequestering CO2 in the deep sea.
- Extended expeditions to Hawaii, the Gulf of California, and the Juan de Fuca Ridge.
- Systematic exploration of the deeper midwater habitats (1,000 and 3,500 meters) of Monterey Canyon, using a new method for quantitative video transecting. Many of the animals observed and collected at those bathypelagic depths are new to science.
- Discovering lava flows on the Juan de Fuca Ridge and collecting geologic samples at the Axial Caldera using a drill to core vertical rock faces and wax cores for basalt glass sampling.
- Investigations of sediment transport and erosion in four major submarine canyons (Ascension, Año Nuevo, Monterey, and Sur Canyons) in the Monterey Bay area and others in Southern California.
- Recorded observations of an unknown species of squid during dives off the coast of Oahu.
- Installation of the seafloor cables as part of the Monterey Ocean Observing System (MOOS).
- Deployment of the first laser raman spectrometer for in situ deep-ocean science.
- Studies of chemosynthetic biological communities in the Monterey Bay area.
MBARI contributors to Tiburon project: Doug Au, Gary Burkhart, Mark Chaffey, Dan Chamberlain, Dave French, Dale Graves, Chris Grech, Bob Herlien, Bill Kirkwood, Mike Matthews, Paul McGill, Ed Mellinger, James Newman, Tom O'Reilly, Andy Pearce, Mark Pickerell, Jim Schofield, Farley Shane, Fitzgerald Smith, Janice Tarrant, Carolyn Todd