Excavating the Deep

Continued from page 2

By Sally Atwood

May 2003

Working at Sea

Deep-sea archaeology is an expensive venture. Typical expeditions last two to three weeks and cost $40,000 to $50,000 a day. Researchers are, therefore, careful to choose areas that are most likely to yield valuable historical information. Areas that are historically interesting, logistically accessible, and promise a high probability of well-preserved sites rise to the top of the list. So far, most of the expeditions have been in the Black Sea and the Mediterranean.

Finding sites can be a tedious process. First, a side-scanning sonar trolls behind the research ship, searching a broad swath of the seafloor and measuring the height of objects that rise from the seabed. Next, a remotely operated vehicle, which is tethered to the ship by a fiber-optic cable, is lowered to examine areas of interest with a video camera. But discoveries are rare. "It's like watching hours and hours of bad TV locked up in a loud steel box," says Brendan Foley, a doctoral candidate in the DeepArch Research Group. He was bitten by the deep-sea archaeology bug on the 1997 Skerki expedition. "It's boredom, boredom, boredom, and then something really exciting happens."

And when it does, the remotely operated vehicle provides real-time feedback to the ship's monitors, giving the team the opportunity to observe the ruins and discuss what they are seeing. On some expeditions, three-person submersibles motor off to verify a site while the rest of the team waits aboard ship for the scientists to return and share their discoveries.

In 2001, Mindell's research team tested an autonomous underwater vehicle on an expedition in the Aegean Sea. Although such vehicles are not yet designed for the precise work of archaeological sites, Mindell believes they have great potential for the future. It is possible to program them to negotiate variable terrain-a challenge tethered vehicles meet with limited success-and they could provide more stability for high-resolution side-scan sonars than is available from a towed platform. Finally, because they don't require fiber-optic cables or ships to tow them, autonomous vehicles could cut expedition costs by about 75 percent, says Mindell.

The research group is focusing on technology that can search the deep, but Brian Bingham, another doctoral candidate in the group, points out that the technology can be used at any depth especially if visibility is limited. "It's really about the technology not the depth," he says. "It's about using remote sensing to deliver that precision for interpretation."

No matter how this new field develops, MIT scientists and engineers will be at the head of the pack. Robert Ballard, who discovered the wreck of the Titanic and is one of Mindell's research colleagues, commends Mindell on his leadership in helping to create a new academic discipline. "He fully understands all aspects of the challenge we face before deep-sea archaeology is mainstreamed within the academic community, and he is doing all within his power to ensure this challenge will be met."

The sea and the intersection of his two loves-history and engineering-fascinate Mindell. "Most of the shipwrecks out there aren't findable with today's technology," he says. "There's a lot to be done in the future that we just can't do today."