UNDERWATER EYES
BY PETER B. BRACE
Sitting on a stool inside a tiny shed on a hay cart perched on a bluff somewhere along the South Shore, Garner Corby is watching two monitors as streams of data pulse up their screens at half-second intervals.

Ship rescuer using ocean current measuring meter to study beach sand movement on Nantucket

The shed, built by Nantucket High School shop students, is the site of data collection for a water-borne sand transport study being done by Resolve Marine owner Joseph Farrell.

Farrell's company rescues stranded ships from sandbars and other perilous situations at sea, and, as an emergency first-responder that also handles hazardous material cleanups such as oil spills, is responsible for safeguarding 45 percent of all oil tankers entering U. S. waters. After 30 years of watching the effects of ocean currents on shoals and sand, Farrell wanted to know the how and the why of sand transport in seawater.

To do this, he teamed up with engineers Sandy Williams and Todd Morrison of Nobska Engineering, who invented an ocean-current-measuring meter called the MAVS-3, and with coastal scientist Steve Elgar of the Woods Hole Oceanographic Institute.

Operating from Sand Watch Central, a mobile shed sited in the dunes, above, Garner Corby, top, monitors data flowing from two meters off the South Shore measuring ocean currents and sand transport.

"I'm using my 30 years of rescuing ships to learn how to rescue beaches," said Farrell. "I've hooked up with these scientists to determine how the weather phenomena here are moving these sands around the Nantucket shoreline."

Two MAVS-3s are planted off the South Shore at intervals of 290 and 490 feet from the shoreline, and submerged 11 and 13 feet deep, respectively. They are connected to the shed's computers by low voltage cables, which transfer the data to the computers. These current meters measure the speed, direction and sand content of the water at the molecular level using light beams.

"They actually measure particulate movement through the water," said Corby. "You can tell when there's a lot of sand movement based on a high reading."

Corby, a landscaper during the warmer months on Nantucket, is Farrell's logistics manager of sorts, keeping the data shack's computer systems and heater functioning while logging weather data and working with Farrell by phone.

Because Farrell's meters are still collecting data as part of a two-week survey before putting it up on his Web site, www.coastalrecovery.org/, and setting it up to stream in as it is collected by the computers in his shed, he is not ready to go public with his unfinished results or the location of the research shed along with his intentions for the use of his data.

"We can actually tell how much particulate sand is moving along the beach and close to the beach and further out from the beach," said Farrell. "These meters are connected to our portable lab and all that data will be coming on the Internet with a live Web cam looking at the surf."

However, Farrell did say he hopes to be able to plant his MAVS-3 meters all around the island to model how sand moves along Nantucket's shores.

Uses of the patented current meter can only be imagined at this point, but could certainly include private property owners who want to determine the movement of sand onto and off their beaches when

applying for erosion control permits. I