Ken Sea

A vehicle that switches modes

The vehicle, known until now as the Hybrid Remotely Operated Vehicle, or HROV, will be able to work in the deepest parts of the ocean, from 6,500 meters to 11,000 meters (21,500 feet to 36,000 feet), a depth currently unreachable for routine ocean research. Scientists also plan to use it to explore remote, difficult-to-reach areas, including under the Arctic ice cap.
[Editor's note: On May 31, 2009, Nereus dove to the deepest part of the ocean—Challenger Deep in the Mariana Trench. Read the article and interviews with engineers who built Nereus.]
Engineers and ship's crew will be able to transform Nereus from a free-swimming vehicle for wide-area ocean surveys to a vehicle tethered by a cable to a surface ship that can be used for or close-up investigation and sampling of seafloor rocks and organisms. The transformation will take 6 to 8 hours and happen on the ship's deck.
“Nereus best fits the image of our vehicle, which engineers can change shape at sea for various science needs,” said Andy Bowen, the WHOI engineer overseeing the vehicle’s design and development.
Bowen was among a panel of judges from WHOI and engineering consulting groups that selected Nereus from 22 entries in a naming contest open to junior high, high school, and college students who participate in the California-based Marine Advanced Technology Education (MATE) Center.
The program provides students in the U.S. and Canada opportunity to explore marine-related careers through internship programs, and it sponsors an annual remotely operated vehicle design competition.
“The students thought it would be appropriate to name it after a Greek god who combined two forms,” said Kelly Miller, an oceanography and chemistry teacher at Monterey High School in California who coordinated the winning name submission for a team of six sophomores, juniors, and seniors.

A vehicle that switches modes

Nereus (rhymes with “serious”) keeps with a tradition in the WHOI Deep Submergence Laboratory of naming vehicles for mythical Greek figures. Among others in the WHOI-operated fleet of vehicles are Jason (a fabled adventurer and ocean explorer), Argo (a ship used by Jason), and Medea (the mythical wife of Jason).
Several teams proposed names for the new vehicle taken from mythology, including the Japanese dragon god Ryujin, the Greek god of wind Aiolos, and the Greek god of the sea Poseidon. Ultimately, Bowen said Nereus was selected because “the name most appropriately represented the vehicle’s ability to switch modes as needed by scientists.”
The $5-million, battery-operated vehicle will be the first ever designed to transform from a guided, tethered robot to a free-swimming vehicle. Each capability offers advantages to deep-sea researchers. In its autonomous mode, the vehicle will be able to fly on pre-programmed missions over swaths of ocean bottom to map the seafloor, to gather remote data, or to search for scientific targets such as hydrothermal vents.
In its tethered mode, it will remain connected via a hair-thin, 25-mile long cable that will enable scientists on the surface ship to send instant commands to the mechanical arm, used for gathering samples of interesting undersea rocks and organisms.
Scheduled for launch in 2007
Sea trials will take place offshore Woods Hole in early 2007, and scientists will plan to use it for research later that year at Challenger Deep, a trench in the Pacific Ocean southwest of Guam. It is the deepest area of any ocean, deeper than Mount Everest is high, extending almost 11,000 meters (36,000 feet) beneath the sea surface.