Exosuit for uber-divers
An international team of archaeologists plans to return this month to the site of an ancient shipwreck off a Greek island. This time, they will have the aid of an advanced diving suit that will give them much more time to probe for new artifacts.
Part robot and part submarine, the lightweight suit, called the Exosuit, is intended to allow a diver to work for long periods at depths of more than 1,000 feet, avoiding time-consuming decompression periods. The suit provides a diver with freedom of movement because of a propulsion system and from an unusual set of rotating joints developed by Phil Nuytten, an explorer and diving technology specialist.
Evocative of the Iron Man movies and their hero, Tony Stark, the aluminum-alloy suit allows the operator to sit on a bicycle-type seat. It is connected to the surface by a high-speed fiber-optic network that relays high-definition video, and it has robotic grippers that will allow divers to manipulate artifacts found at the site.
The Exosuit has a self-contained life-support system designed to allow divers to work as long as 21/ days without surfacing, though at first, the shifts will be much shorter. Its rotary joints are extremely resilient; the smallest, at the wrist, can withstand up to six tons of pressure on a small surface area, Nuytten said.
“You feel like you are in a segmented suit of armor,” said Bren- dan Foley, an archaeologist at Woods Hole Oceanographic Institution in Massachusetts and a director of the shipwreck project who tested the suit this summer. “It’s funny — I was imagining I was going to feel like Tony Stark, but I felt a lot like Lancelot.”
Nuytco, a company founded by Nuytten, has made similar atmospheric diving suits for rescue operations for many of the world’s navies.
The suits are virtually weightless underwater, and a version developed for the U.S. Office of Naval Research will allow divers to swim with flippers for long periods at great depths.
The shipwreck, off the island of Antikythera, was discovered by Greek divers in 1900. A Roman vessel that is believed to have sunk during the first century B.C., it held the renowned Antikythera Mechanism, a mechanical device for predicting celestial movement, along with luxury goods like pottery and bronze statues.
Since the original discovery, the Antikythera wreck was explored only once — by Jacques Cousteau for several weeks in 1976 — until the fall of 2012, when a team of divers from Woods Hole and a Greek government agency, the Hellenic Ephorate of Underwater Antiquities, began a more systematic exploration of the waters around the island.
The site also holds a second shipwreck, and there is some historical evidence that the two vessels were traveling together, perhaps carrying material from the conquests of the Roman general Lucius Cornelius Sulla to be displayed in victory parades in Rome.
Records from the original dive indicate that one marble statue was dropped during efforts to recover it.
It is also possible that some objects that were moved from the shipwreck and mistaken for boulders are also artifacts.
But the project is as much about experimenting with new diving technology as it is about field archaeology, said David Mindell, an engineering professor at the Massachusetts Institute of Technology who has specialized in marine systems.
“Brendan is really the only one who is doing what he is doing, especially in the deeper waters,” he said of Foley. “That stuff is basically land archaeology translated to scuba gear.”
This is the third year the divers will operate at the site. On each expedition, they have added advanced technologies.
Previously, they used closedcircuit rebreathers — devices that scrub carbon dioxide from exhaled breath, allowing the diver to inhale it again — and diver propulsion vehicles equipped with highresolution cameras. Because of the depth of the wreck, even with those systems, divers were limited to just 30 minutes of exploration. They were able to find new artifacts scattered over a wide area, including pottery, a ship’s anchor and a range of bronze objects that have not yet been recovered.
On this year’s expedition, they will also use several underwater robots, including an autonomous vehicle called the Iver, which will be operated by scientists from the Australian Center for Marine Robotics. That will make it possible to create a 3-D map of the shipwreck sites.
Foley said he hoped the Exosuit would be used for up to three dives each day during the monthlong expedition, with each dive lasting two to three hours.
A small group of divers will share the Exosuit, with others using equipment that requires decompression.
This year, the expedition will initially map the site, and divers will cover the area carefully with metal detectors, Foley said. Many of the largest artifacts have been removed. The shipwreck itself stretches almost 150 feet, and the divers will have to work at depths of about 180 feet to almost 500 feet.