April 30, 03

Remotely Operated Vehicles

The remotely operated vehicle (ROV) that we are using throughout the cruise is the Phantom S-2, produced by Deep Ocean Engineering from San Leandro, California (Figure at right). There are different classes of ROVs; from the small “flying eyeballs” to the larger workhorses utilized by the petroleum industry. The Phantom S-2 is a mid-range low cost ROV at approximately $50,000 for the basic unit. After all the technical equipment an upgrades are included the cost of our Superphanton is approximately $250,000. The peripheral equipment in this case might include, cameras, samplers and navigation systems. The Phantom S-2 is a unit that can be used for a wide variety of jobs. NOAA’s National Undersea Research Center (NURC) from UNC-Wilmington has used this ROV for wide range surveying in the Gulf of Mexico, site-specific video and still image data collection, and investigation of potentially contaminated sites. That’s right – investigation was needed to study a toxic site under the Arctic ice. In this case the ROV was used to explore a location potentially harmful (and certainly dangerous) to scuba divers.

In our case we are working with an ROV that can, if necessary be handled by a two-man team. It weighs 120 lbs. and is equipped with 4 thrusters each powered by a ¼ horsepower motor. The ROV runs on 110V A/C power, the same as most electronics in an average home. This means that the ROV is easy to power and never needs to be recharged. Unlike submersibles which normally have a 3 or 4 hour run-time, an ROV can run indefinitely, as long as there is a pilot above the water at the controls. The ROV is also extremely versatile with respect to the variety of platforms from which it can work, such as a dock, a 30 ft. boat or a large research vessel. The ROV can also accommodate a number of surveying tools. On our mission, we’ve mounted a digital still camera with a 3.0 mega pixel capability, a strobe, a mini-DV color video recorder, temperature gauge and depth gauge, and a manipulator arm for acquiring small samples.

The Phantom S-2 ROV is made with a fiberglass body and mounted within a steel cage for protection. Its overall size is approximately 2’ wide x 4’ long x 1.5’ tall. If maintained properly ROVs can last over 15 years. The NURC ROV is now 15. When the ROV is used for research it is billed out at almost $1000 per day – this helps to pay the technicians, maintain the ROV, and recover the initial cost of the unit ($500,000).

Becoming an ROV technician and operator is achievable, though not simple. It is the culmination of many hard, fun years of work, according to Lance Horn, the ROV operator for NURC at UNC-W. Lance started his career in the US Navy 30 years ago as an ocean mechanic. After graduating from Florida Institute of Technology with an AS in Underwater Technologies in 1985, he arrived at NURC, where he began his work as a hard hat diver. He continued to gain ground with technical qualifications including mixed gas diving, diver medical technician training, and operating many sorts of underwater vehicles. Lance has since become one of the nation’s leading experts in the use of ROVs for science. (at right: scientists repair the damaged ROV)

During each of the ROV dives we follow a pre-determined transect (a path in a straight line) that covers areas we have designated necessary to research. These transects were chosen based on new maps – generated on the Oculina Coral Banks 2002 mission last October – selecting areas where coral might be found. When the ROV is lowered into the water, it is on a tether line and cable that link the ROV to the ship, and also connect the cameras and thrusters to the technician’s controls on deck. When following a transect the operator must contend with current, the ship’s speed and direction, and changing topography of the seafloor. Some of the things the researchers are looking for using the ROV are fish, invertebrates, coral formations and substrate (seafloor) type. These transects are used as a sampling of what is found within the adjacent area and for comparison with data previously collected in the same area. (at left: computer screen image of map track)